Add image processing support for AVIF

The encode/decode is implemented in a WebAssembly module built from a
small C wrapper around libavif. Bundled libraries (statically linked,
compiled with the WASI SDK):

* libavif v1.4.1 (container + codec glue)
* libaom v3.14.1 (AV1 encoder + decoder)
* dav1d 1.5.3 (AV1 decoder)
* libyuv (Chromium pin) for color conversion
* parson for JSON message passing across the wasm boundary

HDR handling on the encoder:

* SDR images are written as BT.709 / sRGB / BT.601 (8-bit).
* 10-bit and up are written as BT.2020 primaries with PQ (SMPTE
  ST 2084) transfer and BT.2020-NCL matrix coefficients, signalled
  via CICP.
* Adobe-style SDR+gainmap inputs (e.g. Lightroom HDR exports) are
  baked into a single true-HDR image in BT.2020/PQ at 10-bit, with
  the CLLI (Content Light Level Information) box carried through so
  HDR-capable clients can tone-map correctly.

Limitations:

* Animated input (animated WebP/GIF) is collapsed to its first frame
  when re-encoded as AVIF; animated AVIF output is not yet supported.

Fixes #7837

common/himage/image.go

@@ -43,6 +43,23 @@ type ImageConfigProvider interface {
 	GetImageConfig() image.Config
 }
 
+// ColorPropertiesProvider provides access to CICP color properties (for HDR images).
+// Images implementing this interface preserve color space information through processing.
+type ColorPropertiesProvider interface {
+	GetColorPrimaries() int
+	GetTransferCharacteristics() int
+	GetMatrixCoefficients() int
+}
+
+// HasColorProperties returns true if the image has non-zero color properties that should be preserved.
+func HasColorProperties(img image.Image) bool {
+	if cpp, ok := img.(ColorPropertiesProvider); ok {
+		// Consider it as having properties if any value is non-zero.
+		return cpp.GetColorPrimaries() > 0 || cpp.GetTransferCharacteristics() > 0 || cpp.GetMatrixCoefficients() > 0
+	}
+	return false
+}
+
 // FrameDurationsToGifDelays converts frame durations in milliseconds to
 // GIF delays in 100ths of a second.
 func FrameDurationsToGifDelays(frameDurations []int) []int {

config/testconfig/testconfig.go

@@ -68,6 +68,9 @@ func GetTestDeps(fs afero.Fs, cfg config.Provider, beforeInit ...func(*deps.Deps
 			warpc.Options{
 				PoolSize: 1,
 			},
+			warpc.Options{
+				PoolSize: 1,
+			},
 		),
 	}
 	for _, f := range beforeInit {

docs/.vscode/extensions.json

@@ -1,7 +0,0 @@
-{
-  "recommendations": [
-    "DavidAnson.vscode-markdownlint",
-    "EditorConfig.EditorConfig",
-    "streetsidesoftware.code-spell-checker"
-  ]
-}

go.mod

@@ -68,7 +68,7 @@ require (
 	github.com/spf13/pflag v1.0.10
 	github.com/tdewolff/minify/v2 v2.24.13
 	github.com/tdewolff/parse/v2 v2.8.12
-	github.com/tetratelabs/wazero v1.11.0
+	github.com/tetratelabs/wazero v1.11.1-0.20260521072212-475a1f8f0dc3
 	github.com/yuin/goldmark v1.8.2
 	github.com/yuin/goldmark-emoji v1.0.6
 	go.uber.org/automaxprocs v1.5.3

go.sum

@@ -504,6 +504,8 @@ github.com/tdewolff/test v1.0.12 h1:7F21DqIajswxuche0geHdrUZRCWE4oko4b7bcmkkrxk=
 github.com/tdewolff/test v1.0.12/go.mod h1:XPuWBzvdUzhCuxWO1ojpXsyzsA5bFoS3tO/Q3kFuTG8=
 github.com/tetratelabs/wazero v1.11.0 h1:+gKemEuKCTevU4d7ZTzlsvgd1uaToIDtlQlmNbwqYhA=
 github.com/tetratelabs/wazero v1.11.0/go.mod h1:eV28rsN8Q+xwjogd7f4/Pp4xFxO7uOGbLcD/LzB1wiU=
+github.com/tetratelabs/wazero v1.11.1-0.20260521072212-475a1f8f0dc3 h1:0Jpp+tPkvALC9hcZUYOj/6yWYvUIV/kKoxRDj0a6zk4=
+github.com/tetratelabs/wazero v1.11.1-0.20260521072212-475a1f8f0dc3/go.mod h1:LvKtzl2RqO4gyF27BiXU+nKAjcV8f38U+kP/q2vgxh0=
 github.com/ugorji/go/codec v1.2.7 h1:YPXUKf7fYbp/y8xloBqZOw2qaVggbfwMlI8WM3wZUJ0=
 github.com/ugorji/go/codec v1.2.7/go.mod h1:WGN1fab3R1fzQlVQTkfxVtIBhWDRqOviHU95kRgeqEY=
 github.com/woodsbury/decimal128 v1.3.0 h1:8pffMNWIlC0O5vbyHWFZAt5yWvWcrHA+3ovIIjVWss0=

hugolib/site.go

@@ -204,10 +204,12 @@ func NewHugoSites(cfg deps.DepsCfg) (*HugoSites, error) {
 	var (
 		poolSizeKatex = 2
 		poolSizeWebP  = 1
+		poolSizeAvif  = 1
 	)
 	if n := config.GetNumWorkerMultiplier(); n > 1 {
 		poolSizeKatex = min(n, 8)
 		poolSizeWebP = max(2, n/2)
+		poolSizeAvif = max(2, n/2)
 	}
 
 	var logger loggers.Logger
@@ -282,6 +284,14 @@ func NewHugoSites(cfg deps.DepsCfg) (*HugoSites, error) {
 				Infof:               logger.InfoCommand("webp").Logf,
 				Warnf:               logger.WarnCommand("webp").Logf,
 			},
+			// Avif options.
+			warpc.Options{
+				CompilationCacheDir: compilationCacheDir,
+				PoolSize:            poolSizeAvif,
+				Memory:              384, // 384 MiB (4096 MiB Max)
+				Infof:               logger.InfoCommand("avif").Logf,
+				Warnf:               logger.WarnCommand("avif").Logf,
+			},
 		),
 	}
 

internal/warpc/avif.go

@@ -0,0 +1,426 @@
+// Copyright 2025 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package warpc
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+	"io"
+
+	"github.com/gohugoio/hugo/common/hugio"
+)
+
+var (
+	_ SourceProvider      = AvifInput{}
+	_ DestinationProvider = AvifInput{}
+)
+
+type AvifInput struct {
+	Source      hugio.SizeReader `json:"-"`       // Will be sent in a separate stream.
+	Destination io.Writer        `json:"-"`       // Will be used to write the result to.
+	Options     map[string]any   `json:"options"` // Config options.
+	Params      map[string]any   `json:"params"`  // Command params (width, height, etc.).
+}
+
+func (a AvifInput) GetSource() hugio.SizeReader {
+	return a.Source
+}
+
+func (a AvifInput) GetDestination() io.Writer {
+	return a.Destination
+}
+
+type AvifOutput struct {
+	Params CommonImageProcessingParams `json:"params"`
+}
+
+type AvifCodec struct {
+	d func() (Dispatcher[AvifInput, AvifOutput], error)
+}
+
+func (d *AvifCodec) DecodeConfig(r io.Reader) (image.Config, error) {
+	dd, err := d.d()
+	if err != nil {
+		return image.Config{}, err
+	}
+
+	rr, err := hugio.ToSizeReader(r)
+	if err != nil {
+		return image.Config{}, err
+	}
+	message := Message[AvifInput]{
+		Header: Header{
+			Version:       1,
+			Command:       "config",
+			RequestKinds:  []string{MessageKindJSON, MessageKindBlob},
+			ResponseKinds: []string{MessageKindJSON},
+		},
+
+		Data: AvifInput{
+			Source: rr,
+		},
+	}
+
+	out, err := dd.Execute(context.Background(), message)
+	if err != nil {
+		return image.Config{}, err
+	}
+	return image.Config{
+		Width:      out.Data.Params.Width,
+		Height:     out.Data.Params.Height,
+		ColorModel: color.RGBAModel,
+	}, nil
+}
+
+func (d *AvifCodec) Decode(r io.Reader) (image.Image, error) {
+	dd, err := d.d()
+	if err != nil {
+		return nil, err
+	}
+
+	source, err := hugio.ToSizeReader(r)
+	if err != nil {
+		return nil, err
+	}
+
+	var destination bytes.Buffer
+
+	message := Message[AvifInput]{
+		Header: Header{
+			Version:       1,
+			Command:       "decode",
+			RequestKinds:  []string{MessageKindJSON, MessageKindBlob},
+			ResponseKinds: []string{MessageKindJSON, MessageKindBlob},
+		},
+
+		Data: AvifInput{
+			Source:      source,
+			Destination: &destination,
+			Options:     map[string]any{},
+		},
+	}
+
+	out, err := dd.Execute(context.Background(), message)
+	if err != nil {
+		return nil, err
+	}
+
+	w, h, stride, depth := out.Data.Params.Width, out.Data.Params.Height, out.Data.Params.Stride, out.Data.Params.Depth
+	if w == 0 || h == 0 || stride == 0 {
+		return nil, fmt.Errorf("received invalid image dimensions: %dx%d stride %d", w, h, stride)
+	}
+
+	// For 10+ bit HDR images, the C code returns 16-bit RGBA data.
+	isHDR := depth > 8
+
+	// libavif returns 16-bit data in native (little-endian) byte order,
+	// but Go's NRGBA64 expects big-endian. Swap bytes for HDR images.
+	if isHDR {
+		pix := destination.Bytes()
+		for i := 0; i < len(pix); i += 2 {
+			pix[i], pix[i+1] = pix[i+1], pix[i]
+		}
+	}
+
+	if len(out.Data.Params.FrameDurations) > 0 {
+		img := &AnimatedImage{
+			frameDurations:          out.Data.Params.FrameDurations,
+			loopCount:               avifLoopCountToGo(out.Data.Params.LoopCount),
+			depth:                   depth,
+			colorPrimaries:          out.Data.Params.ColorPrimaries,
+			transferCharacteristics: out.Data.Params.TransferCharacteristics,
+			matrixCoefficients:      out.Data.Params.MatrixCoefficients,
+			maxCLL:                  out.Data.Params.MaxCLL,
+			maxPALL:                 out.Data.Params.MaxPALL,
+		}
+
+		frameSize := stride * h
+		pixLen := len(destination.Bytes())
+		if frameSize == 0 || pixLen%frameSize != 0 {
+			return nil, fmt.Errorf("decoded AVIF buffer size %d is not a multiple of frame size %d", pixLen, frameSize)
+		}
+		frameCount := pixLen / frameSize
+		if frameCount != len(out.Data.Params.FrameDurations) {
+			return nil, fmt.Errorf("decoded AVIF frame count %d does not match frame durations %d", frameCount, len(out.Data.Params.FrameDurations))
+		}
+		frames := make([]image.Image, frameCount)
+		for i := 0; i < len(frames); i++ {
+			frameBytes := destination.Bytes()[i*frameSize : (i+1)*frameSize]
+			if isHDR {
+				// NRGBA64 for HDR - libavif returns non-premultiplied alpha.
+				frameImg := &image.NRGBA64{
+					Pix:    frameBytes,
+					Stride: stride,
+					Rect:   image.Rect(0, 0, w, h),
+				}
+				frames[i] = frameImg
+			} else {
+				// NRGBA - libavif returns non-premultiplied alpha.
+				frameImg := &image.NRGBA{
+					Pix:    frameBytes,
+					Stride: stride,
+					Rect:   image.Rect(0, 0, w, h),
+				}
+				frames[i] = frameImg
+			}
+		}
+		img.SetFrames(frames)
+		return img, nil
+	}
+
+	if isHDR {
+		// NRGBA64 for HDR - libavif returns non-premultiplied alpha.
+		// Wrap in AnimatedImage to preserve color properties through the pipeline.
+		baseImg := &image.NRGBA64{
+			Pix:    destination.Bytes(),
+			Stride: stride,
+			Rect:   image.Rect(0, 0, w, h),
+		}
+		img := &AnimatedImage{
+			Image:                   baseImg,
+			frames:                  []image.Image{baseImg},
+			depth:                   depth,
+			colorPrimaries:          out.Data.Params.ColorPrimaries,
+			transferCharacteristics: out.Data.Params.TransferCharacteristics,
+			matrixCoefficients:      out.Data.Params.MatrixCoefficients,
+			maxCLL:                  out.Data.Params.MaxCLL,
+			maxPALL:                 out.Data.Params.MaxPALL,
+		}
+		return img, nil
+	}
+
+	// NRGBA - libavif returns non-premultiplied alpha.
+	img := &image.NRGBA{
+		Pix:    destination.Bytes(),
+		Stride: stride,
+		Rect:   image.Rect(0, 0, w, h),
+	}
+
+	return img, nil
+}
+
+// avifLoopCountToGo translates libavif's repetitionCount (-1 = infinite,
+// 0 = play once, N = N repetitions) to the convention used by image/gif and
+// the WebP codec (0 = infinite, -1 = play once, N = N repetitions).
+func avifLoopCountToGo(repetitionCount int) int {
+	switch repetitionCount {
+	case -1, -2: // AVIF_REPETITION_COUNT_INFINITE, AVIF_REPETITION_COUNT_UNKNOWN
+		return 0
+	case 0:
+		return -1
+	default:
+		return repetitionCount
+	}
+}
+
+func (d *AvifCodec) Encode(w io.Writer, src image.Image, options map[string]any) error {
+	dd, err := d.d()
+	if err != nil {
+		return err
+	}
+
+	var cmd string
+	var source hugio.SizeReader
+	var params map[string]any = make(map[string]any)
+
+	switch img := src.(type) {
+	case *AnimatedImage:
+		// AnimatedImage wraps HDR images to preserve color properties.
+		// For single-frame, extract the underlying image and add color properties.
+		frames := img.GetFrames()
+		if len(frames) == 0 {
+			return fmt.Errorf("AnimatedImage has no frames")
+		}
+		// Get color properties from AnimatedImage.
+		params["colorPrimaries"] = img.GetColorPrimaries()
+		params["transferCharacteristics"] = img.GetTransferCharacteristics()
+		params["matrixCoefficients"] = img.GetMatrixCoefficients()
+		params["maxCLL"] = img.GetMaxCLL()
+		params["maxPALL"] = img.GetMaxPALL()
+
+		// Handle the first frame based on its type.
+		firstFrame := frames[0]
+		switch frame := firstFrame.(type) {
+		case *image.NRGBA64:
+			cmd = "encodeNRGBA"
+			pix := make([]byte, len(frame.Pix))
+			for i := 0; i < len(pix); i += 2 {
+				pix[i], pix[i+1] = frame.Pix[i+1], frame.Pix[i]
+			}
+			var err error
+			source, err = hugio.ToSizeReader(bytes.NewReader(pix))
+			if err != nil {
+				return err
+			}
+			params["width"] = frame.Rect.Dx()
+			params["height"] = frame.Rect.Dy()
+			params["stride"] = frame.Stride
+			params["depth"] = img.GetDepth()
+			if params["depth"] == 0 {
+				params["depth"] = 10 // Default to 10-bit for HDR.
+			}
+		case *image.NRGBA:
+			cmd = "encodeNRGBA"
+			var err error
+			source, err = hugio.ToSizeReader(bytes.NewReader(frame.Pix))
+			if err != nil {
+				return err
+			}
+			params["width"] = frame.Rect.Dx()
+			params["height"] = frame.Rect.Dy()
+			params["stride"] = frame.Stride
+			params["depth"] = 8
+		default:
+			// Convert to NRGBA64 for HDR or NRGBA for SDR.
+			b := firstFrame.Bounds()
+			if img.GetDepth() > 8 {
+				newImg := image.NewNRGBA64(image.Rect(0, 0, b.Dx(), b.Dy()))
+				draw.Draw(newImg, newImg.Bounds(), firstFrame, b.Min, draw.Src)
+				cmd = "encodeNRGBA"
+				pix := make([]byte, len(newImg.Pix))
+				for i := 0; i < len(pix); i += 2 {
+					pix[i], pix[i+1] = newImg.Pix[i+1], newImg.Pix[i]
+				}
+				var err error
+				source, err = hugio.ToSizeReader(bytes.NewReader(pix))
+				if err != nil {
+					return err
+				}
+				params["width"] = newImg.Rect.Dx()
+				params["height"] = newImg.Rect.Dy()
+				params["stride"] = newImg.Stride
+				params["depth"] = img.GetDepth()
+			} else {
+				newImg := image.NewNRGBA(image.Rect(0, 0, b.Dx(), b.Dy()))
+				draw.Draw(newImg, newImg.Bounds(), firstFrame, b.Min, draw.Src)
+				cmd = "encodeNRGBA"
+				var err error
+				source, err = hugio.ToSizeReader(bytes.NewReader(newImg.Pix))
+				if err != nil {
+					return err
+				}
+				params["width"] = newImg.Rect.Dx()
+				params["height"] = newImg.Rect.Dy()
+				params["stride"] = newImg.Stride
+				params["depth"] = 8
+			}
+		}
+	case *image.NRGBA64:
+		// 16-bit RGBA for HDR images.
+		// Go's NRGBA64 is big-endian, but libavif expects little-endian.
+		// Copy and swap bytes.
+		cmd = "encodeNRGBA"
+		pix := make([]byte, len(img.Pix))
+		for i := 0; i < len(pix); i += 2 {
+			pix[i], pix[i+1] = img.Pix[i+1], img.Pix[i]
+		}
+		var err error
+		source, err = hugio.ToSizeReader(bytes.NewReader(pix))
+		if err != nil {
+			return err
+		}
+		params["width"] = img.Rect.Dx()
+		params["height"] = img.Rect.Dy()
+		params["stride"] = img.Stride
+		params["depth"] = 10 // Encode HDR as 10-bit AVIF.
+	case *image.RGBA64:
+		// 16-bit RGBA for HDR images.
+		// Go's RGBA64 is big-endian, but libavif expects little-endian.
+		// Copy and swap bytes.
+		cmd = "encodeNRGBA"
+		pix := make([]byte, len(img.Pix))
+		for i := 0; i < len(pix); i += 2 {
+			pix[i], pix[i+1] = img.Pix[i+1], img.Pix[i]
+		}
+		var err error
+		source, err = hugio.ToSizeReader(bytes.NewReader(pix))
+		if err != nil {
+			return err
+		}
+		params["width"] = img.Rect.Dx()
+		params["height"] = img.Rect.Dy()
+		params["stride"] = img.Stride
+		params["depth"] = 10 // Encode HDR as 10-bit AVIF.
+	case *image.NRGBA:
+		cmd = "encodeNRGBA"
+		var err error
+		source, err = hugio.ToSizeReader(bytes.NewReader(img.Pix))
+		if err != nil {
+			return err
+		}
+		params["width"] = img.Rect.Dx()
+		params["height"] = img.Rect.Dy()
+		params["stride"] = img.Stride
+		params["depth"] = 8
+	case *image.Gray:
+		cmd = "encodeGray"
+		var err error
+		source, err = hugio.ToSizeReader(bytes.NewReader(img.Pix))
+		if err != nil {
+			return err
+		}
+		params["width"] = img.Rect.Dx()
+		params["height"] = img.Rect.Dy()
+		params["stride"] = img.Stride
+		params["depth"] = 8
+	case *image.Gray16:
+		// 16-bit grayscale for HDR.
+		cmd = "encodeGray"
+		var err error
+		source, err = hugio.ToSizeReader(bytes.NewReader(img.Pix))
+		if err != nil {
+			return err
+		}
+		params["width"] = img.Rect.Dx()
+		params["height"] = img.Rect.Dy()
+		params["stride"] = img.Stride
+		params["depth"] = 10
+	default:
+		// Check if source is HDR (RGBA64 color model) to preserve quality.
+		if src.ColorModel() == color.RGBA64Model || src.ColorModel() == color.NRGBA64Model {
+			b := src.Bounds()
+			newImg := image.NewNRGBA64(image.Rect(0, 0, b.Dx(), b.Dy()))
+			draw.Draw(newImg, newImg.Bounds(), src, b.Min, draw.Src)
+			return d.Encode(w, newImg, options)
+		}
+		// Convert to NRGBA and try again.
+		b := src.Bounds()
+		newImg := image.NewNRGBA(image.Rect(0, 0, b.Dx(), b.Dy()))
+		draw.Draw(newImg, newImg.Bounds(), src, b.Min, draw.Src)
+		return d.Encode(w, newImg, options)
+	}
+
+	message := Message[AvifInput]{
+		Header: Header{
+			Version:       1,
+			Command:       cmd,
+			RequestKinds:  []string{MessageKindJSON, MessageKindBlob},
+			ResponseKinds: []string{MessageKindJSON, MessageKindBlob},
+		},
+
+		Data: AvifInput{
+			Source:      source,
+			Destination: w,
+			Options:     options,
+			Params:      params,
+		},
+	}
+
+	_, err = dd.Execute(context.Background(), message)
+	return err
+}

internal/warpc/avif_color_test.go

@@ -0,0 +1,64 @@
+package warpc_test
+
+import (
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+	"github.com/gohugoio/hugo/hugolib"
+)
+
+func TestAvifColorPropertyPreservation(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping in short mode")
+	}
+
+	// dock-75-hdr.avif is Lightroom-style SDR+gain-map HDR; the decoder bakes the
+	// gain map into a single BT.2020/PQ HDR AVIF.
+	files := `
+-- hugo.toml --
+-- assets/dock.avif --
+sourcefilename: ../../resources/testdata/bep/dock-75-hdr.avif
+-- layouts/home.html --
+{{ $dock := resources.Get "dock.avif" }}
+Dock: {{ $dock.Width }}x{{ $dock.Height }}
+{{ $dockReencoded := $dock.Process "avif q75" }}
+DockReencoded: {{ $dockReencoded.RelPermalink }}
+`
+
+	b, err := hugolib.TestE(t, files, hugolib.TestOptWithOSFs())
+	b.Assert(err, qt.IsNil)
+	b.AssertFileContent("public/index.html", "Dock: 1024x683")
+
+	// Check color properties of re-encoded files using exiftool
+	checkColorProps := func(t *testing.T, name, filepath string, expectedPrimaries, expectedTransfer string) {
+		cmd := exec.Command("exiftool", "-ColorPrimaries", "-TransferCharacteristics", filepath)
+		output, err := cmd.Output()
+		if err != nil {
+			t.Skipf("exiftool not available: %v", err)
+		}
+		outputStr := string(output)
+		t.Logf("Color properties for %s:\n%s", name, outputStr)
+
+		if !strings.Contains(outputStr, expectedPrimaries) {
+			t.Errorf("%s: Expected color primaries %q, got:\n%s", name, expectedPrimaries, outputStr)
+		}
+		if !strings.Contains(outputStr, expectedTransfer) {
+			t.Errorf("%s: Expected transfer characteristics %q, got:\n%s", name, expectedTransfer, outputStr)
+		}
+	}
+
+	// Find the generated files - use Cfg.WorkingDir
+	publicDir := filepath.Join(b.Cfg.WorkingDir, "public")
+	t.Logf("Looking in: %s", publicDir)
+
+	// dock-75-hdr.avif has a gain map, so the output should be BT.2020/PQ.
+	dockMatches, _ := filepath.Glob(filepath.Join(publicDir, "dock_hu*.avif"))
+	if len(dockMatches) > 0 {
+		checkColorProps(t, "dock", dockMatches[0], "BT.2020", "PQ")
+	} else {
+		t.Error("No dock AVIF file found in output")
+	}
+}

internal/warpc/avif_integration_test.go

@@ -0,0 +1,68 @@
+package warpc_test
+
+import (
+	"strings"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+	"github.com/gohugoio/hugo/hugolib"
+)
+
+func TestAvifBasic(t *testing.T) {
+	files := `
+-- hugo.toml --
+-- assets/sunset.avif --
+sourcefilename: ../../resources/testdata/bep/dock-75-hdr.avif
+-- layouts/home.html --
+{{ $image := resources.Get "sunset.avif" }}
+Width/Height: {{ $image.Width }}/{{ $image.Height }}|
+Decode avif: {{ $jpeg := $image.Process "jpeg" }}|{{ $jpeg.RelPermalink }}|
+Encode avif from JPEG: {{ $avif := $jpeg.Process "avif" }}|{{ $avif.RelPermalink }}|
+Encode avif from avif: {{ $avif := $image.Process "avif" }}|{{ $avif.RelPermalink }}|
+`
+
+	b, err := hugolib.TestE(t, files)
+	b.Assert(err, qt.IsNil)
+	b.AssertFileContent("public/index.html", "Width/Height: 1024/683")
+}
+
+// giphy.avif is an animated AVIF transcoded from giphy.gif (14 frames @ 200ms,
+// infinite loop) via avifenc. Verifies that decode preserves animation, the
+// pipeline runs every frame through resize, the GIF encoder writes a multi-frame
+// GIF, and the libavif "repetitionCount" → Go "LoopCount" inversion (libavif
+// -1 = infinite, image/gif 0 = infinite) is handled at the AVIF decoder boundary.
+func TestAvifAnimatedToGif(t *testing.T) {
+	files := `
+-- hugo.toml --
+disableKinds = ["page", "section", "taxonomy", "term", "sitemap", "robotsTXT", "404"]
+-- assets/giphy.avif --
+sourcefilename: ../../resources/testdata/giphy.avif
+-- layouts/home.html --
+{{ $img := resources.Get "giphy.avif" }}
+{{ $gif := $img.Resize "x60 gif" }}
+{{ $gif.Publish }}
+gif:{{ $gif.RelPermalink }}
+`
+
+	b := hugolib.Test(t, files)
+	rel := b.FileContent("public/index.html")
+
+	var gifFile string
+	for line := range strings.SplitSeq(rel, "\n") {
+		if rest, ok := strings.CutPrefix(line, "gif:"); ok {
+			gifFile = "public" + rest
+			break
+		}
+	}
+	b.Assert(gifFile, qt.Not(qt.Equals), "")
+
+	durations := make([]int, 14)
+	for i := range durations {
+		durations[i] = 200
+	}
+	b.ImageHelper(gifFile).
+		AssertFormat("gif").
+		AssertIsAnimated(true).
+		AssertLoopCount(0).
+		AssertFrameDurations(durations)
+}

internal/warpc/genavif/.gitignore

@@ -0,0 +1,4 @@
+build/
+build_avif/
+libavif/
+aom/

internal/warpc/genavif/Makefile

@@ -0,0 +1,170 @@
+# The library versions to use.
+LIBAVIF_VERSION = v1.4.1
+AOM_VERSION = v3.14.1
+DAV1D_VERSION = 1.5.3
+# Commit used by Chromium, see https://source.chromium.org/chromium/chromium/src/+/main:DEPS?q=libyuv
+LIBYUV_COMMIT = 9d98aaefe7a5e2710aa6175d44da38892400b381
+
+# The path to the WebAssembly SDK. Can be overridden from the command line.
+# e.g., make WASI_SDK_PATH=/path/to/wasi-sdk
+# Download releases from https://github.com/WebAssembly/wasi-sdk/releases.
+# Note that on MacOS, you may need to add some whitelistings in Privacy & Security > Security.
+WASI_SDK_PATH ?= /opt/wasi-sdk
+
+LIBAVIF_BUILD := $(PWD)/build
+LIBAVIF_SRC := $(PWD)/libavif
+LIBAVIF_AOM_SRC := $(LIBAVIF_SRC)/ext/aom
+LIBAVIF_AOM_BUILD = $(LIBAVIF_AOM_SRC)/build.libavif
+LIBAVIF_DAV1D_SRC := $(LIBAVIF_SRC)/ext/dav1d
+LIBAVIF_DAV1D_BUILD := $(LIBAVIF_DAV1D_SRC)/build
+LIBYUV_SRC := $(LIBAVIF_SRC)/ext/libyuv
+LIBYUV_BUILD := $(LIBYUV_SRC)/build
+
+BUILD_WASM := ${LIBAVIF_BUILD}/avif.wasm
+TARGET_WASM_DIR := ../wasm
+
+# Set the compiler and toolchain for WASI
+CC := $(WASI_SDK_PATH)/bin/clang
+CMAKE_TOOLCHAIN_FILE := $(WASI_SDK_PATH)/share/cmake/wasi-sdk-p1.cmake
+
+# Source files for the final WASM binary
+C_SOURCES := avif.c ../deps/parson/parson.c
+
+# Include paths
+C_INCLUDES := -I$(LIBAVIF_SRC)/include -I$(LIBAVIF_AOM_SRC) -I$(LIBAVIF_BUILD)/include -I.
+
+# Libraries to link against
+LD_LIBS := $(LIBAVIF_BUILD)/libavif.a $(LIBAVIF_DAV1D_BUILD)/src/libdav1d.a $(LIBAVIF_BUILD)/libaom.a $(LIBYUV_BUILD)/libyuv.a -lsetjmp
+
+# SIMD + non-trapping FP/int are part of wazero's CoreFeaturesV2, so we can rely
+# on them at runtime. Adding -msimd128 to the library builds lets clang
+# auto-vectorize hot loops in aom/dav1d/libyuv/libavif (none of them ship
+# hand-tuned wasm-simd code).
+LIB_SIMD_FLAGS := -msimd128 -mnontrapping-fptoint
+LIB_CFLAGS := $(LIB_SIMD_FLAGS) -mllvm -wasm-enable-sjlj -mllvm -wasm-use-legacy-eh=false
+
+# Compiler flags for the WASM build
+WASM_CFLAGS := \
+    -O3 \
+    -msimd128 \
+    -mexec-model=command \
+    -mnontrapping-fptoint \
+    -mllvm -wasm-enable-sjlj \
+    -mllvm -wasm-use-legacy-eh=false \
+    -Wl,--export=malloc \
+    -Wl,--export=free \
+    -Wall \
+
+all: $(LIBAVIF_SRC) $(LIBAVIF_AOM_SRC) $(LIBAVIF_DAV1D_SRC) $(LIBYUV_SRC) $(LIBAVIF_BUILD)
+	@echo ">>> Configuring and building C libraries in $(LIBAVIF_BUILD)"
+	cd $(LIBAVIF_AOM_BUILD); \
+	cmake $(LIBAVIF_AOM_SRC) \
+		-DCMAKE_BUILD_TYPE=Release \
+		-DBUILD_SHARED_LIBS=0 \
+		-DENABLE_DOCS=0 \
+		-DENABLE_EXAMPLES=0 \
+		-DENABLE_TESTDATA=0 \
+		-DENABLE_TESTS=0 \
+		-DENABLE_TOOLS=0 \
+		-DAOM_TARGET_CPU=generic \
+		-DCONFIG_RUNTIME_CPU_DETECT=0 \
+		-DCONFIG_MULTITHREAD=0 \
+		-DCONFIG_WEBM_IO=0 \
+		-DCONFIG_AV1_DECODER=1 \
+		-DCONFIG_AV1_ENCODER=1 \
+		-DCMAKE_TOOLCHAIN_FILE=$(CMAKE_TOOLCHAIN_FILE) \
+		-DCMAKE_C_FLAGS="$(LIB_CFLAGS)" \
+		-DCMAKE_CXX_FLAGS="$(LIB_CFLAGS)"
+	cd $(LIBAVIF_AOM_BUILD); \
+	make VERBOSE=1
+	@echo ">>> Copying libaom.a to $(LIBAVIF_BUILD)"
+	cp $(LIBAVIF_AOM_BUILD)/libaom.a $(LIBAVIF_BUILD)/libaom.a
+
+	@echo ">>> Building dav1d with meson"
+	cd $(LIBAVIF_DAV1D_SRC); \
+	meson setup build \
+		--cross-file $(PWD)/wasi-sdk-cross.txt \
+		-Denable_asm=false \
+		-Denable_tools=false \
+		-Denable_tests=false \
+		-Ddefault_library=static \
+		--reconfigure
+	cd $(LIBAVIF_DAV1D_SRC); \
+	ninja -C build -v
+
+	@echo ">>> Building libyuv"
+	mkdir -p $(LIBYUV_BUILD)
+	cd $(LIBYUV_BUILD); \
+	cmake $(LIBYUV_SRC) \
+		-DCMAKE_BUILD_TYPE=Release \
+		-DBUILD_SHARED_LIBS=0 \
+		-DCMAKE_POSITION_INDEPENDENT_CODE=ON \
+		-DCMAKE_TOOLCHAIN_FILE=$(CMAKE_TOOLCHAIN_FILE) \
+		-DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
+		-DCMAKE_C_FLAGS="$(LIB_CFLAGS)" \
+		-DCMAKE_CXX_FLAGS="$(LIB_CFLAGS)"
+	cd $(LIBYUV_BUILD); \
+	make yuv VERBOSE=1
+
+	cd $(LIBAVIF_BUILD); \
+	cmake $(LIBAVIF_SRC) \
+		-DCMAKE_BUILD_TYPE=Release \
+		-DBUILD_SHARED_LIBS=0 \
+		-DAVIF_CODEC_AOM=LOCAL \
+		-DAVIF_LOCAL_AOM=1 \
+		-DAVIF_CODEC_AOM_DECODE=1 \
+		-DAVIF_CODEC_AOM_ENCODE=1 \
+		-DAVIF_CODEC_DAV1D=LOCAL \
+		-DAVIF_LIBYUV=LOCAL \
+		-DCMAKE_TOOLCHAIN_FILE=$(CMAKE_TOOLCHAIN_FILE) \
+		-DCMAKE_C_FLAGS="$(LIB_CFLAGS)" \
+		-DCMAKE_CXX_FLAGS="$(LIB_CFLAGS)"
+
+	cd $(LIBAVIF_BUILD); \
+	make VERBOSE=1
+
+	@echo ">>> Building WebAssembly binary: $(BUILD_WASM)"
+	$(CC) $(WASM_CFLAGS) --sysroot=$(WASI_SDK_PATH)/share/wasi-sysroot $(C_INCLUDES) -o $(BUILD_WASM) $(C_SOURCES) $(LD_LIBS)
+	@echo ">>> Moving the WebAssembly binary: $(TARGET_WASM_DIR)"
+	mv $(BUILD_WASM) $(TARGET_WASM_DIR)
+
+
+# Rule to create the build directory
+$(LIBAVIF_BUILD):
+	@echo ">>> Creating build directory: $(LIBAVIF_BUILD)"
+	@mkdir -p $@
+
+# Rule to clone the libavif source code
+$(LIBAVIF_SRC):
+	@echo ">>> Cloning libavif source code (version: $(LIBAVIF_VERSION))"
+	git clone -b $(LIBAVIF_VERSION) --depth 1 --recursive https://github.com/AOMediaCodec/libavif.git  $(LIBAVIF_SRC)
+	test -d $@
+
+# Rule to clone the aom source code
+$(LIBAVIF_AOM_SRC):
+	@echo ">>> Cloning aom source code (version: $(AOM_VERSION))"
+	git clone -b $(AOM_VERSION) --depth 1 --recursive https://aomedia.googlesource.com/aom $(LIBAVIF_AOM_SRC)
+	mkdir -p $(LIBAVIF_AOM_BUILD)
+	test -d $@
+
+# Rule to clone the dav1d source code
+$(LIBAVIF_DAV1D_SRC):
+	@echo ">>> Cloning dav1d source code (version: $(DAV1D_VERSION))"
+	git clone -b $(DAV1D_VERSION) --depth 1 https://code.videolan.org/videolan/dav1d.git $(LIBAVIF_DAV1D_SRC)
+	test -d $@
+
+# Rule to clone the libyuv source code
+$(LIBYUV_SRC):
+	@echo ">>> Cloning libyuv source code (commit: $(LIBYUV_COMMIT))"
+	git clone --single-branch https://chromium.googlesource.com/libyuv/libyuv $(LIBYUV_SRC)
+	cd $(LIBYUV_SRC) && git checkout $(LIBYUV_COMMIT)
+	test -d $@
+
+
+.PHONY: clean
+
+# Rule to clean up build artifacts
+clean:
+	@echo ">>> Cleaning build artifacts"
+	@rm -rf $(LIBAVIF_BUILD)
+	@rm -rf $(LIBAVIF_SRC)

internal/warpc/genavif/avif.c

@@ -0,0 +1,839 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include "avif/avif.h"
+#include "../deps/parson/parson.h"
+
+void handle_commands(FILE *stream);
+
+int main()
+{
+    // This will read commands from stdin and write responses to stdout
+    // and return 0 when stdin is closed.
+    // Any errors gets reported in the RPC response messages.
+    handle_commands(stdin);
+    return 0;
+}
+
+typedef struct
+{
+    int version;
+    int id;
+    char command[256];
+    char err[256];
+} Header;
+
+typedef struct
+{
+    int width;
+    int height;
+    int stride;
+    int depth; // Bit depth per channel (8, 10, 12, 16).
+    int loopCount;
+    int frameCount;
+    int *frameDurations;
+
+    // CICP color properties.
+    int colorPrimaries;
+    int transferCharacteristics;
+    int matrixCoefficients;
+
+    // HDR CLLI box (max content/picture-average light level, in cd/m^2).
+    int maxCLL;
+    int maxPALL;
+
+} InputParams;
+
+typedef struct
+{
+    float quality;        // between 1 and 100.
+    char compression[32]; // "lossy" or "lossless"
+    int encoderSpeed;     // 1 (slowest, best) to 10 (fastest). 0 means use default.
+} InputOptions;
+
+typedef struct
+{
+    InputOptions options;
+    InputParams params;
+
+} InputData;
+
+typedef struct
+{
+    Header header;
+    InputData data;
+
+} InputMessage;
+
+typedef struct
+{
+    Header header;
+    InputData data;
+
+} OutputMessage;
+
+#define MAX_LINE_LENGTH 4096
+
+InputMessage parse_input_message(const char *line)
+{
+    InputMessage msg = {0};
+
+    JSON_Value *root_value = json_parse_string(line);
+    if (root_value == NULL)
+    {
+        fprintf(stderr, "Error parsing JSON line\n");
+        return msg;
+    }
+
+    if (json_value_get_type(root_value) != JSONObject)
+    {
+        fprintf(stderr, "Error: Line did not parse to a valid JSON object\n");
+        json_value_free(root_value);
+        return msg;
+    }
+
+    JSON_Object *root_object = json_value_get_object(root_value);
+
+    JSON_Object *header_object = json_object_get_object(root_object, "header");
+    if (header_object != NULL)
+    {
+        msg.header.version = (int)json_object_get_number(header_object, "version");
+        msg.header.id = (int)json_object_get_number(header_object, "id");
+        const char *command_str = json_object_get_string(header_object, "command");
+        if (command_str != NULL)
+        {
+            strncpy(msg.header.command, command_str, sizeof(msg.header.command) - 1);
+            msg.header.command[sizeof(msg.header.command) - 1] = '\0';
+        }
+        const char *err_str = json_object_get_string(header_object, "err");
+        if (err_str != NULL)
+        {
+            strncpy(msg.header.err, err_str, sizeof(msg.header.err) - 1);
+            msg.header.err[sizeof(msg.header.err) - 1] = '\0';
+        }
+    }
+
+    JSON_Object *data_object = json_object_get_object(root_object, "data");
+    if (data_object != NULL)
+    {
+        JSON_Object *params_object = json_object_get_object(data_object, "params");
+        if (params_object != NULL)
+        {
+            msg.data.params.width = (int)json_object_get_number(params_object, "width");
+            msg.data.params.height = (int)json_object_get_number(params_object, "height");
+            msg.data.params.stride = (int)json_object_get_number(params_object, "stride");
+            msg.data.params.depth = (int)json_object_get_number(params_object, "depth");
+            msg.data.params.loopCount = (int)json_object_get_number(params_object, "loopCount");
+            msg.data.params.colorPrimaries = (int)json_object_get_number(params_object, "colorPrimaries");
+            msg.data.params.transferCharacteristics = (int)json_object_get_number(params_object, "transferCharacteristics");
+            msg.data.params.matrixCoefficients = (int)json_object_get_number(params_object, "matrixCoefficients");
+            msg.data.params.maxCLL = (int)json_object_get_number(params_object, "maxCLL");
+            msg.data.params.maxPALL = (int)json_object_get_number(params_object, "maxPALL");
+            JSON_Array *durations_array = json_object_get_array(params_object, "frameDurations");
+            if (durations_array != NULL)
+            {
+                size_t count = json_array_get_count(durations_array);
+                msg.data.params.frameCount = count;
+
+                if (count > 0)
+                {
+                    msg.data.params.frameDurations = malloc(sizeof(int) * count);
+                    if (msg.data.params.frameDurations != NULL)
+                    {
+                        for (size_t i = 0; i < count; i++)
+                        {
+                            msg.data.params.frameDurations[i] = (int)json_array_get_number(durations_array, i);
+                        }
+                    }
+                    else
+                    {
+                        // Malloc failed.
+                        msg.data.params.frameCount = 0;
+                    }
+                }
+            }
+        }
+        JSON_Object *options_object = json_object_get_object(data_object, "options");
+        if (options_object != NULL)
+        {
+            msg.data.options.quality = (float)json_object_get_number(options_object, "quality");
+            msg.data.options.encoderSpeed = (int)json_object_get_number(options_object, "encoderSpeed");
+            const char *compression_str = json_object_get_string(options_object, "compression");
+            if (compression_str != NULL)
+            {
+                strncpy(msg.data.options.compression, compression_str, sizeof(msg.data.options.compression) - 1);
+                msg.data.options.compression[sizeof(msg.data.options.compression) - 1] = '\0';
+            }
+        }
+    }
+
+    json_value_free(root_value);
+    return msg;
+}
+
+static void write_blob(uint32_t id, const uint8_t *data, uint32_t size)
+{
+    uint8_t output_blob_header[16];
+    uint32_t output_blob_id = id;
+    uint32_t output_blob_size = size;
+    // See https://github.com/bep/textandbinarywriter
+    const char magic[] = {'T', 'A', 'K', '3', '5', 'E', 'M', '1'};
+    memcpy(output_blob_header, magic, 8);
+    memcpy(&output_blob_header[8], &output_blob_id, sizeof(output_blob_id));
+    memcpy(&output_blob_header[12], &output_blob_size, sizeof(output_blob_size));
+
+    fwrite(output_blob_header, 1, sizeof(output_blob_header), stdout);
+    fwrite(data, 1, (size_t)size, stdout);
+    fflush(stdout);
+}
+
+void write_output_message(const OutputMessage *msg)
+{
+    JSON_Value *root_value = json_value_init_object();
+    JSON_Object *root_object = json_value_get_object(root_value);
+
+    // Header
+    JSON_Value *header_value = json_value_init_object();
+    JSON_Object *header_object = json_value_get_object(header_value);
+    json_object_set_value(root_object, "header", header_value);
+    json_object_set_number(header_object, "version", msg->header.version);
+    json_object_set_number(header_object, "id", msg->header.id);
+    json_object_set_string(header_object, "err", msg->header.err);
+
+    // Data
+    if (msg->data.params.width > 0)
+    {
+        JSON_Value *data_value = json_value_init_object();
+        JSON_Object *data_object = json_value_get_object(data_value);
+        json_object_set_value(root_object, "data", data_value);
+
+        JSON_Value *params_value = json_value_init_object();
+        JSON_Object *params_object = json_value_get_object(params_value);
+        json_object_set_value(data_object, "params", params_value);
+
+        json_object_set_number(params_object, "width", msg->data.params.width);
+        json_object_set_number(params_object, "height", msg->data.params.height);
+        json_object_set_number(params_object, "stride", msg->data.params.stride);
+        json_object_set_number(params_object, "depth", msg->data.params.depth);
+        json_object_set_number(params_object, "colorPrimaries", msg->data.params.colorPrimaries);
+        json_object_set_number(params_object, "transferCharacteristics", msg->data.params.transferCharacteristics);
+        json_object_set_number(params_object, "matrixCoefficients", msg->data.params.matrixCoefficients);
+        json_object_set_number(params_object, "maxCLL", msg->data.params.maxCLL);
+        json_object_set_number(params_object, "maxPALL", msg->data.params.maxPALL);
+        if (msg->data.params.frameDurations != NULL)
+        {
+            JSON_Value *durations_value = json_value_init_array();
+            JSON_Array *durations_array = json_value_get_array(durations_value);
+            for (int i = 0; i < msg->data.params.frameCount; i++)
+            {
+                json_array_append_number(durations_array, msg->data.params.frameDurations[i]);
+            }
+
+            json_object_set_value(params_object, "frameDurations", durations_value);
+            json_object_set_number(params_object, "loopCount", msg->data.params.loopCount);
+        }
+    }
+
+    char *serialized_string = json_serialize_to_string(root_value);
+    fprintf(stdout, "%s\n", serialized_string);
+    fflush(stdout);
+
+    json_free_serialized_string(serialized_string);
+    json_value_free(root_value);
+}
+
+void handle_commands(FILE *stream)
+{
+
+    char line[MAX_LINE_LENGTH];
+
+    while (fgets(line, sizeof(line), stream) != NULL)
+    {
+        InputMessage input = {0};
+        uint8_t *blob_data = NULL;
+        uint32_t blob_size = 0;
+
+        // Remove newline character if present
+        line[strcspn(line, "\n")] = 0;
+
+        if (strlen(line) == 0)
+        {
+            continue;
+        }
+
+        input = parse_input_message(line);
+
+        // Next in stream is a blob header defined in https://github.com/bep/textandbinaryreader
+        // T', 'A', 'K', '3', '5', 'E', 'M', '1' id uint32, size uint32
+        uint8_t blob_header[16];
+        size_t read_bytes = fread(blob_header, 1, sizeof(blob_header), stream);
+        if (read_bytes != sizeof(blob_header))
+        {
+            fprintf(stderr, "Error reading blob header\n");
+            goto cleanup;
+        }
+        uint32_t blob_id = *(uint32_t *)&blob_header[8];
+        blob_size = *(uint32_t *)&blob_header[12];
+        blob_data = malloc((size_t)blob_size);
+        if (blob_data == NULL)
+        {
+            fprintf(stderr, "[%d] Error allocating memory for blob data\n", blob_id);
+            goto cleanup;
+        }
+        read_bytes = fread(blob_data, 1, (size_t)blob_size, stream);
+        if (read_bytes != (size_t)blob_size)
+        {
+            fprintf(stderr, "[%d]  Error reading blob data (size: %llu read: %zu) \n", blob_id, (unsigned long long)blob_size, read_bytes);
+            goto cleanup;
+        }
+
+        OutputMessage output = {0};
+        output.header = input.header;
+
+        if (strcmp(input.header.command, "decode") == 0)
+        {
+            avifDecoder *decoder = avifDecoderCreate();
+            if (decoder == NULL)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to create AVIF decoder");
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            decoder->ignoreExif = AVIF_TRUE;
+            decoder->ignoreXMP = AVIF_TRUE;
+            decoder->maxThreads = 1;
+            // dav1d decodes ~2-4x faster than aom under WASM.
+            decoder->codecChoice = AVIF_CODEC_CHOICE_DAV1D;
+            // Request gain map pixels when present (e.g. Lightroom HDR exports).
+            decoder->imageContentToDecode = AVIF_IMAGE_CONTENT_ALL;
+
+            avifResult result = avifDecoderSetIOMemory(decoder, blob_data, blob_size);
+            if (result != AVIF_RESULT_OK)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to set IO memory: %s", avifResultToString(result));
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            result = avifDecoderParse(decoder);
+            if (result != AVIF_RESULT_OK)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to parse AVIF: %s", avifResultToString(result));
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            // If a gain map is present (e.g. Adobe-style SDR+gainmap HDR from Lightroom),
+            // bake it into a single true-HDR image in BT.2020/PQ at 10-bit.
+            // The downstream pipeline then sees a normal HDR AVIF; SDR clients/displays
+            // tone-map automatically.
+            avifBool hasGainMap = (decoder->image->gainMap != NULL && decoder->image->gainMap->image != NULL);
+            if (hasGainMap)
+            {
+                // Need a full frame to apply the gain map.
+                result = avifDecoderNextImage(decoder);
+                if (result != AVIF_RESULT_OK)
+                {
+                    snprintf(output.header.err, sizeof(output.header.err), "Failed to decode AVIF for gain map: %s", avifResultToString(result));
+                    avifDecoderDestroy(decoder);
+                    write_output_message(&output);
+                    goto cleanup;
+                }
+
+                avifRGBImage outRGB;
+                memset(&outRGB, 0, sizeof(outRGB));
+                avifRGBImageSetDefaults(&outRGB, decoder->image);
+                outRGB.format = AVIF_RGB_FORMAT_RGBA;
+                outRGB.depth = 16;
+                if (avifRGBImageAllocatePixels(&outRGB) != AVIF_RESULT_OK)
+                {
+                    snprintf(output.header.err, sizeof(output.header.err), "Failed to allocate RGB pixels for gain map apply");
+                    avifDecoderDestroy(decoder);
+                    write_output_message(&output);
+                    goto cleanup;
+                }
+
+                // Target the alternate (full-HDR) endpoint: alternateHdrHeadroom = log2(HDR/SDR).
+                float hdrHeadroom = 0.0f;
+                const avifUnsignedFraction *h = &decoder->image->gainMap->alternateHdrHeadroom;
+                if (h->d != 0)
+                {
+                    hdrHeadroom = (float)h->n / (float)h->d;
+                }
+
+                avifContentLightLevelInformationBox outCLLI = {0};
+                avifResult applyResult = avifImageApplyGainMap(
+                    decoder->image,
+                    decoder->image->gainMap,
+                    hdrHeadroom,
+                    AVIF_COLOR_PRIMARIES_BT2020,
+                    AVIF_TRANSFER_CHARACTERISTICS_PQ,
+                    &outRGB,
+                    &outCLLI,
+                    NULL);
+                if (applyResult != AVIF_RESULT_OK)
+                {
+                    snprintf(output.header.err, sizeof(output.header.err), "Failed to apply gain map: %s", avifResultToString(applyResult));
+                    avifRGBImageFreePixels(&outRGB);
+                    avifDecoderDestroy(decoder);
+                    write_output_message(&output);
+                    goto cleanup;
+                }
+
+                output.data.params.width = outRGB.width;
+                output.data.params.height = outRGB.height;
+                // Tell the Go side we're 10-bit HDR so it wraps in NRGBA64 and re-encodes as HDR.
+                output.data.params.depth = 10;
+                output.data.params.stride = outRGB.rowBytes;
+                output.data.params.frameCount = 1;
+                output.data.params.colorPrimaries = AVIF_COLOR_PRIMARIES_BT2020;
+                output.data.params.transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_PQ;
+                output.data.params.matrixCoefficients = AVIF_MATRIX_COEFFICIENTS_BT2020_NCL;
+                output.data.params.maxCLL = outCLLI.maxCLL;
+                output.data.params.maxPALL = outCLLI.maxPALL;
+
+                size_t blob_out_size = (size_t)outRGB.rowBytes * outRGB.height;
+                write_output_message(&output);
+                write_blob(output.header.id, outRGB.pixels, blob_out_size);
+
+                avifRGBImageFreePixels(&outRGB);
+                avifDecoderDestroy(decoder);
+                goto cleanup;
+            }
+
+            output.data.params.width = decoder->image->width;
+            output.data.params.height = decoder->image->height;
+            output.data.params.loopCount = decoder->repetitionCount;
+            output.data.params.frameCount = decoder->imageCount;
+            output.data.params.depth = decoder->image->depth;
+            output.data.params.colorPrimaries = decoder->image->colorPrimaries;
+            output.data.params.transferCharacteristics = decoder->image->transferCharacteristics;
+            output.data.params.matrixCoefficients = decoder->image->matrixCoefficients;
+
+            // For 10+ bit images (HDR), use 16-bit RGB to preserve quality.
+            // 8-bit depth: 4 bytes per pixel (RGBA, 1 byte each)
+            // 16-bit depth: 8 bytes per pixel (RGBA, 2 bytes each)
+            int rgb_depth = (decoder->image->depth > 8) ? 16 : 8;
+            uint32_t bytes_per_pixel = (rgb_depth == 16) ? 8 : 4;
+            uint32_t row_bytes = decoder->image->width * bytes_per_pixel;
+
+            output.data.params.stride = row_bytes;
+
+            size_t frame_size = (size_t)row_bytes * decoder->image->height;
+            size_t all_frames_size = frame_size * decoder->imageCount;
+            uint8_t *all_frames_data = malloc(all_frames_size);
+            if (all_frames_data == NULL)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to allocate memory for decoded image");
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            if (decoder->imageCount > 1)
+            {
+                output.data.params.frameDurations = malloc(sizeof(int) * decoder->imageCount);
+                if (output.data.params.frameDurations == NULL)
+                {
+                    snprintf(output.header.err, sizeof(output.header.err), "Failed to allocate memory for frame durations");
+                    free(all_frames_data);
+                    avifDecoderDestroy(decoder);
+                    write_output_message(&output);
+                    goto cleanup;
+                }
+            }
+
+            // Set up RGB conversion parameters.
+            avifRGBImage rgb;
+            memset(&rgb, 0, sizeof(rgb));
+            avifRGBImageSetDefaults(&rgb, decoder->image);
+            rgb.format = AVIF_RGB_FORMAT_RGBA;
+            rgb.depth = rgb_depth;
+            rgb.rowBytes = row_bytes;
+
+            int frame_index = 0;
+            avifResult next_result;
+            while ((next_result = avifDecoderNextImage(decoder)) == AVIF_RESULT_OK)
+            {
+                rgb.pixels = all_frames_data + (frame_index * frame_size);
+
+                avifResult conv_result = avifImageYUVToRGB(decoder->image, &rgb);
+                if (conv_result != AVIF_RESULT_OK)
+                {
+                    snprintf(output.header.err, sizeof(output.header.err), "Failed to convert to RGBA: %s", avifResultToString(conv_result));
+                    free(all_frames_data);
+                    if (output.data.params.frameDurations != NULL)
+                    {
+                        free(output.data.params.frameDurations);
+                        output.data.params.frameDurations = NULL;
+                    }
+                    avifDecoderDestroy(decoder);
+                    write_output_message(&output);
+                    goto cleanup;
+                }
+
+                if (decoder->imageCount > 1)
+                {
+                    uint64_t duration_ms = (uint64_t)(decoder->imageTiming.duration * 1000.0);
+                    output.data.params.frameDurations[frame_index] = (int)duration_ms;
+                }
+
+                frame_index++;
+            }
+
+            if (next_result != AVIF_RESULT_NO_IMAGES_REMAINING)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to decode AVIF frame %d: %s", frame_index, avifResultToString(next_result));
+                free(all_frames_data);
+                if (output.data.params.frameDurations != NULL)
+                {
+                    free(output.data.params.frameDurations);
+                    output.data.params.frameDurations = NULL;
+                }
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            if (frame_index != decoder->imageCount)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Decoded %d frames, expected %d", frame_index, decoder->imageCount);
+                free(all_frames_data);
+                if (output.data.params.frameDurations != NULL)
+                {
+                    free(output.data.params.frameDurations);
+                    output.data.params.frameDurations = NULL;
+                }
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            write_output_message(&output);
+            write_blob(output.header.id, all_frames_data, all_frames_size);
+
+            free(all_frames_data);
+            if (output.data.params.frameDurations != NULL)
+            {
+                free(output.data.params.frameDurations);
+                output.data.params.frameDurations = NULL;
+            }
+            avifDecoderDestroy(decoder);
+
+            goto cleanup;
+        }
+        else if (strcmp(input.header.command, "config") == 0)
+        {
+            avifDecoder *decoder = avifDecoderCreate();
+            if (decoder == NULL)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to create AVIF decoder");
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            decoder->ignoreExif = AVIF_TRUE;
+            decoder->ignoreXMP = AVIF_TRUE;
+            decoder->maxThreads = 1;
+            decoder->codecChoice = AVIF_CODEC_CHOICE_DAV1D;
+
+            avifResult result = avifDecoderSetIOMemory(decoder, blob_data, blob_size);
+            if (result != AVIF_RESULT_OK)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to set IO memory: %s", avifResultToString(result));
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            result = avifDecoderParse(decoder);
+            if (result != AVIF_RESULT_OK)
+            {
+                snprintf(output.header.err, sizeof(output.header.err), "Failed to parse AVIF: %s", avifResultToString(result));
+                avifDecoderDestroy(decoder);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            output.data.params.width = decoder->image->width;
+            output.data.params.height = decoder->image->height;
+            output.data.params.depth = decoder->image->depth;
+            output.data.params.loopCount = decoder->repetitionCount;
+            output.data.params.frameCount = decoder->imageCount;
+
+            avifDecoderDestroy(decoder);
+
+            write_output_message(&output);
+        }
+        else if (strcmp(input.header.command, "encodeNRGBA") == 0)
+        {
+            int width = input.data.params.width;
+            int height = input.data.params.height;
+            int depth = input.data.params.depth;
+            int stride = input.data.params.stride;
+
+            // Default depth to 8 if not specified.
+            if (depth == 0) {
+                depth = 8;
+            }
+            // For HDR (10+ bit), input comes as 16-bit RGBA.
+            int rgb_depth = (depth > 8) ? 16 : 8;
+            int bytes_per_pixel = (rgb_depth > 8) ? 8 : 4;
+            if (stride == 0) {
+                stride = width * bytes_per_pixel;
+            }
+            float quality = input.data.options.quality;
+            const char* compression = input.data.options.compression;
+
+            if (width == 0 || height == 0) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeNRGBA: width and height must be > 0");
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            // Create image with the target bit depth for encoding.
+            avifImage *image = avifImageCreate(width, height, depth, AVIF_PIXEL_FORMAT_YUV444);
+            if (!image) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeNRGBA: Failed to create avifImage");
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            // Set color properties from input if provided, otherwise use depth-based defaults.
+            // This preserves the original color space when re-encoding (e.g., BT.709 SDR vs BT.2020 HDR).
+            if (input.data.params.colorPrimaries > 0) {
+                image->colorPrimaries = input.data.params.colorPrimaries;
+                image->transferCharacteristics = input.data.params.transferCharacteristics;
+                image->matrixCoefficients = input.data.params.matrixCoefficients;
+            } else if (depth > 8) {
+                // Default for 10-bit+: BT.2020/PQ (HDR).
+                image->colorPrimaries = AVIF_COLOR_PRIMARIES_BT2020;
+                image->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_PQ;
+                image->matrixCoefficients = AVIF_MATRIX_COEFFICIENTS_BT2020_NCL;
+            } else {
+                // Default for 8-bit: BT.709/sRGB (SDR).
+                image->colorPrimaries = AVIF_COLOR_PRIMARIES_BT709;
+                image->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_SRGB;
+                image->matrixCoefficients = AVIF_MATRIX_COEFFICIENTS_BT601;
+            }
+            image->yuvRange = AVIF_RANGE_FULL;
+
+            // CLLI carries HDR peak/avg light levels from a baked gain map.
+            if (input.data.params.maxCLL > 0 || input.data.params.maxPALL > 0) {
+                image->clli.maxCLL = (uint16_t)input.data.params.maxCLL;
+                image->clli.maxPALL = (uint16_t)input.data.params.maxPALL;
+            }
+
+            avifRGBImage rgb;
+            avifRGBImageSetDefaults(&rgb, image);
+            rgb.format = AVIF_RGB_FORMAT_RGBA;
+            rgb.depth = rgb_depth;
+            rgb.pixels = (uint8_t *)blob_data;
+            rgb.rowBytes = stride;
+
+            avifResult result = avifImageRGBToYUV(image, &rgb);
+            if (result != AVIF_RESULT_OK) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeNRGBA: Failed to convert to YUV: %s", avifResultToString(result));
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            avifEncoder *encoder = avifEncoderCreate();
+            if (!encoder) {
+                 snprintf(output.header.err, sizeof(output.header.err), "encodeNRGBA: Failed to create encoder");
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+			encoder->codecChoice = AVIF_CODEC_CHOICE_AOM;
+
+            if (strcmp(compression, "lossless") == 0) {
+                encoder->quality = AVIF_QUALITY_LOSSLESS;
+                encoder->qualityAlpha = AVIF_QUALITY_LOSSLESS;
+            } else {
+                // Map Hugo quality 1-100 to libavif quality 0-100 (higher is better).
+                if (quality < 1) quality = 1;
+                if (quality > 100) quality = 100;
+                int avif_quality = (int)((quality - 1.0) / 99.0 * 100.0);
+                encoder->quality = avif_quality;
+                encoder->qualityAlpha = avif_quality;
+            }
+            // Range 0 (slowest, best quality) to 10 (fastest).
+            encoder->speed = (input.data.options.encoderSpeed >= 1 && input.data.options.encoderSpeed <= 10)
+                ? input.data.options.encoderSpeed
+                : 10;
+            encoder->autoTiling = AVIF_TRUE;
+
+            result = avifEncoderAddImage(encoder, image, 1, AVIF_ADD_IMAGE_FLAG_SINGLE);
+            if (result != AVIF_RESULT_OK) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeNRGBA: Failed to add image to encoder: %s", avifResultToString(result));
+                avifEncoderDestroy(encoder);
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            avifRWData raw = { NULL, 0 };
+            result = avifEncoderFinish(encoder, &raw);
+            if (result != AVIF_RESULT_OK) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeNRGBA: Failed to finish encoding: %s", avifResultToString(result));
+                avifEncoderDestroy(encoder);
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            write_output_message(&output);
+            write_blob(output.header.id, raw.data, raw.size);
+
+            avifRWDataFree(&raw);
+            avifEncoderDestroy(encoder);
+            avifImageDestroy(image);
+            
+            goto cleanup;
+        }
+        else if (strcmp(input.header.command, "encodeGray") == 0)
+        {
+            int width = input.data.params.width;
+            int height = input.data.params.height;
+            int depth = input.data.params.depth;
+            int stride = input.data.params.stride;
+
+            // Default depth to 8 if not specified.
+            if (depth == 0) {
+                depth = 8;
+            }
+            int bytes_per_sample = (depth > 8) ? 2 : 1;
+            if (stride == 0) {
+                stride = width * bytes_per_sample;
+            }
+            float quality = input.data.options.quality;
+            const char* compression = input.data.options.compression;
+
+            if (width == 0 || height == 0) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeGray: width and height must be > 0");
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            avifImage *image = avifImageCreate(width, height, depth, AVIF_PIXEL_FORMAT_YUV400);
+            if (!image) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeGray: Failed to create avifImage");
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            // Set color properties from input if provided, otherwise use depth-based defaults.
+            if (input.data.params.colorPrimaries > 0) {
+                image->colorPrimaries = input.data.params.colorPrimaries;
+                image->transferCharacteristics = input.data.params.transferCharacteristics;
+                image->matrixCoefficients = input.data.params.matrixCoefficients;
+            } else if (depth > 8) {
+                // Default for 10-bit+: BT.2020/PQ (HDR).
+                image->colorPrimaries = AVIF_COLOR_PRIMARIES_BT2020;
+                image->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_PQ;
+                image->matrixCoefficients = AVIF_MATRIX_COEFFICIENTS_BT2020_NCL;
+            } else {
+                // Default for 8-bit: BT.709/sRGB (SDR).
+                image->colorPrimaries = AVIF_COLOR_PRIMARIES_BT709;
+                image->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_SRGB;
+                image->matrixCoefficients = AVIF_MATRIX_COEFFICIENTS_BT601;
+            }
+            image->yuvRange = AVIF_RANGE_FULL;
+
+            if (input.data.params.maxCLL > 0 || input.data.params.maxPALL > 0) {
+                image->clli.maxCLL = (uint16_t)input.data.params.maxCLL;
+                image->clli.maxPALL = (uint16_t)input.data.params.maxPALL;
+            }
+
+            avifResult alloc_result = avifImageAllocatePlanes(image, AVIF_PLANES_YUV);
+            if (alloc_result != AVIF_RESULT_OK) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeGray: Failed to allocate planes: %s", avifResultToString(alloc_result));
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+            uint8_t *src = blob_data;
+            uint8_t *dst = image->yuvPlanes[AVIF_CHAN_Y];
+            size_t row_bytes = width * bytes_per_sample;
+            for (int i = 0; i < height; ++i) {
+                memcpy(dst, src, row_bytes);
+                src += stride;
+                dst += image->yuvRowBytes[AVIF_CHAN_Y];
+            }
+
+
+            avifEncoder *encoder = avifEncoderCreate();
+            if (!encoder) {
+                 snprintf(output.header.err, sizeof(output.header.err), "encodeGray: Failed to create encoder");
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+			encoder->codecChoice = AVIF_CODEC_CHOICE_AOM;
+
+            if (strcmp(compression, "lossless") == 0) {
+                encoder->quality = AVIF_QUALITY_LOSSLESS;
+            } else {
+                // Map Hugo quality 1-100 to libavif quality 0-100 (higher is better).
+                if (quality < 1) quality = 1;
+                if (quality > 100) quality = 100;
+                int avif_quality = (int)((quality - 1.0) / 99.0 * 100.0);
+                encoder->quality = avif_quality;
+            }
+            encoder->qualityAlpha = AVIF_QUALITY_LOSSLESS;
+            encoder->speed = (input.data.options.encoderSpeed >= 1 && input.data.options.encoderSpeed <= 10)
+                ? input.data.options.encoderSpeed
+                : 10;
+            encoder->autoTiling = AVIF_TRUE;
+
+            avifResult result = avifEncoderAddImage(encoder, image, 1, AVIF_ADD_IMAGE_FLAG_SINGLE);
+            if (result != AVIF_RESULT_OK) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeGray: Failed to add image to encoder: %s", avifResultToString(result));
+                avifEncoderDestroy(encoder);
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            avifRWData raw = { NULL, 0 };
+            result = avifEncoderFinish(encoder, &raw);
+            if (result != AVIF_RESULT_OK) {
+                snprintf(output.header.err, sizeof(output.header.err), "encodeGray: Failed to finish encoding: %s", avifResultToString(result));
+                avifEncoderDestroy(encoder);
+                avifImageDestroy(image);
+                write_output_message(&output);
+                goto cleanup;
+            }
+
+            write_output_message(&output);
+            write_blob(output.header.id, raw.data, raw.size);
+
+            avifRWDataFree(&raw);
+            avifEncoderDestroy(encoder);
+            avifImageDestroy(image);
+            
+            goto cleanup;
+        }
+        else
+        {
+            snprintf(output.header.err, sizeof(output.header.err), "Unknown command: %s", input.header.command);
+            write_output_message(&output);
+        }
+
+    cleanup:
+        if (blob_data != NULL)
+        {
+            free(blob_data);
+        }
+        if (input.data.params.frameDurations != NULL)
+        {
+            free(input.data.params.frameDurations);
+        }
+    }
+}

internal/warpc/genavif/go.mod

@@ -0,0 +1,3 @@
+module gohugoio/hugo/internal/warpc/genavif
+
+go 1.21

internal/warpc/genavif/wasi-sdk-cross.txt

@@ -0,0 +1,21 @@
+[binaries]
+c       = '/opt/wasi-sdk/bin/clang'
+cpp     = '/opt/wasi-sdk/bin/clang++'
+ar      = '/opt/wasi-sdk/bin/llvm-ar'
+strip   = '/opt/wasi-sdk/bin/llvm-strip'
+
+[built-in options]
+# _POSIX_C_SOURCE exposes clock_gettime in wasi-libc's <time.h>.
+# dav1d's atomics get translated to WASM atomic ops; we enable wazero's
+# experimental threads feature on the Go side to accept them at runtime.
+# -msimd128 / -mnontrapping-fptoint let clang auto-vectorize hot loops;
+# both features are in wazero's CoreFeaturesV2 set.
+c_args          = ['--target=wasm32-wasip1', '--sysroot=/opt/wasi-sdk/share/wasi-sysroot', '-D_POSIX_C_SOURCE=200112L', '-msimd128', '-mnontrapping-fptoint']
+c_link_args     = ['--target=wasm32-wasip1', '--sysroot=/opt/wasi-sdk/share/wasi-sysroot']
+default_library = 'static'
+
+[host_machine]
+system     = 'wasi'
+cpu_family = 'wasm32'
+cpu        = 'wasm32'
+endian     = 'little'

internal/warpc/genwebp/Makefile

@@ -6,6 +6,7 @@ LIBWEBP_VERSION = v1.6.0
 # e.g., make WASI_SDK_PATH=/path/to/wasi-sdk
 # Download releases from https://github.com/WebAssembly/wasi-sdk/releases.
 # Note that on MacOS, you may need to add some whitelistings in Privacy & Security > Security.
+# Note that you also need wasm-validate from WebAssembly Binary Toolkit (WABT) installed.
 WASI_SDK_PATH ?= /opt/wasi-sdk
 
 BUILD_DIR := build
@@ -15,10 +16,10 @@ LIBWEBP_SRC := libwebp
 
 # Set the compiler and toolchain for WASI
 CC := $(WASI_SDK_PATH)/bin/clang
-CMAKE_TOOLCHAIN_FILE := $(WASI_SDK_PATH)/share/cmake/wasi-sdk.cmake
+CMAKE_TOOLCHAIN_FILE := $(WASI_SDK_PATH)/share/cmake/wasi-sdk-p1.cmake
 
 # Source files for the final WASM binary
-C_SOURCES := webp.c deps/parson/parson.c
+C_SOURCES := webp.c ../deps/parson/parson.c
 
 # Include paths
 C_INCLUDES := -I$(LIBWEBP_SRC)/src -I$(BUILD_DIR)/src -I.
@@ -62,7 +63,6 @@ all: $(LIBWEBP_SRC) $(BUILD_DIR)
 	mv $(BUILD_WASM) $(TARGET_WASM_DIR)
 
 
-
 # Rule to create the build directory
 $(BUILD_DIR):
 	@echo ">>> Creating build directory: $(BUILD_DIR)"

internal/warpc/genwebp/webp.c

@@ -19,7 +19,7 @@
 #include <webp/decode.h>
 #include "webp/demux.h"
 #include <webp/mux.h>
-#include "deps/parson/parson.h"
+#include "../deps/parson/parson.h"
 
 void handle_commands(FILE *stream);
 

internal/warpc/warpc.go

@@ -54,6 +54,9 @@ var quickjsWasm []byte
 //go:embed wasm/webp.wasm
 var webpWasm []byte
 
+//go:embed wasm/avif.wasm
+var avifWasm []byte
+
 // Header is in both the request and response.
 type Header struct {
 	// Major version of the protocol.
@@ -587,6 +590,7 @@ func newDispatcher[Q, R any](opts Options) (*dispatcherPool[Q, R], error) {
 	// Page size is 64KB.
 	numPages := opts.Memory * 1024 / 64
 	runtimeConfig := wazero.NewRuntimeConfig().WithMemoryLimitPages(uint32(numPages))
+	runtimeConfig = runtimeConfig.WithCoreFeatures(api.CoreFeaturesV2 | experimental.CoreFeaturesExceptionHandling | experimental.CoreFeaturesThreads)
 
 	if opts.CompilationCacheDir != "" {
 		compilationCache, err := wazero.NewCompilationCacheWithDir(opts.CompilationCacheDir)
@@ -788,6 +792,7 @@ func (d *lazyDispatcher[Q, R]) start() (Dispatcher[Q, R], error) {
 type Dispatchers struct {
 	katex *lazyDispatcher[KatexInput, KatexOutput]
 	webp  *lazyDispatcher[WebpInput, WebpOutput]
+	avif  *lazyDispatcher[AvifInput, AvifOutput]
 }
 
 func (d *Dispatchers) Katex() (Dispatcher[KatexInput, KatexOutput], error) {
@@ -798,12 +803,22 @@ func (d *Dispatchers) Webp() (Dispatcher[WebpInput, WebpOutput], error) {
 	return d.webp.start()
 }
 
+func (d *Dispatchers) Avif() (Dispatcher[AvifInput, AvifOutput], error) {
+	return d.avif.start()
+}
+
 func (d *Dispatchers) NewWepCodec() (*WebpCodec, error) {
 	return &WebpCodec{
 		d: d.Webp,
 	}, nil
 }
 
+func (d *Dispatchers) NewAvifCodec() (*AvifCodec, error) {
+	return &AvifCodec{
+		d: d.Avif,
+	}, nil
+}
+
 func (d *Dispatchers) Close() error {
 	var errs []error
 	if d.katex.started {
@@ -825,7 +840,7 @@ func (d *Dispatchers) Close() error {
 // AllDispatchers creates all the dispatchers for the warpc package.
 // Note that the individual dispatchers are started lazily.
 // Remember to call Close on the returned Dispatchers when done.
-func AllDispatchers(katexOpts, webpOpts Options) *Dispatchers {
+func AllDispatchers(katexOpts, webpOpts, avifOpts Options) *Dispatchers {
 	if err := katexOpts.init(); err != nil {
 		panic(err)
 	}
@@ -840,10 +855,12 @@ func AllDispatchers(katexOpts, webpOpts Options) *Dispatchers {
 	}
 
 	webpOpts.Main = Binary{Name: "webp", Data: webpWasm}
+	avifOpts.Main = Binary{Name: "avif", Data: avifWasm}
 
 	dispatchers := &Dispatchers{
 		katex: &lazyDispatcher[KatexInput, KatexOutput]{opts: katexOpts},
 		webp:  &lazyDispatcher[WebpInput, WebpOutput]{opts: webpOpts},
+		avif:  &lazyDispatcher[AvifInput, AvifOutput]{opts: avifOpts},
 	}
 
 	return dispatchers

internal/warpc/webp.go

@@ -38,10 +38,21 @@ type CommonImageProcessingParams struct {
 	Height   int  `json:"height,omitempty"`
 	Stride   int  `json:"stride,omitempty"`
 	HasAlpha bool `json:"hasAlpha,omitempty"`
+	Depth    int  `json:"depth,omitempty"` // Bit depth per channel (8, 10, 12, 16).
 
 	// For animated images.
 	FrameDurations []int `json:"frameDurations,omitempty"`
 	LoopCount      int   `json:"loopCount,omitempty"`
+
+	// CICP color properties (for AVIF).
+	ColorPrimaries          int `json:"colorPrimaries,omitempty"`
+	TransferCharacteristics int `json:"transferCharacteristics,omitempty"`
+	MatrixCoefficients      int `json:"matrixCoefficients,omitempty"`
+
+	// HDR CLLI box (cd/m^2). Populated by the AVIF decoder when a gain map has
+	// been baked into a PQ HDR image, and re-applied by the encoder.
+	MaxCLL  int `json:"maxCLL,omitempty"`
+	MaxPALL int `json:"maxPALL,omitempty"`
 }
 
 /*
@@ -102,11 +113,6 @@ func (d *WebpCodec) Decode(r io.Reader) (image.Image, error) {
 
 	var destination bytes.Buffer
 
-	// Commands:
-	// encodeNRGBA
-	// encodeGray
-	// decode
-	// config
 	message := Message[WebpInput]{
 		Header: Header{
 			Version:       1,
@@ -134,7 +140,7 @@ func (d *WebpCodec) Decode(r io.Reader) (image.Image, error) {
 
 	if len(out.Data.Params.FrameDurations) > 0 {
 		// Animated WebP (always RGBA).
-		img := &WEBP{
+		img := &AnimatedImage{
 			frameDurations: out.Data.Params.FrameDurations,
 			loopCount:      out.Data.Params.LoopCount,
 		}
@@ -257,7 +263,7 @@ func (d *WebpCodec) Encode(w io.Writer, img image.Image, opts map[string]any) er
 		imageBytes = v.Pix
 		stride = v.Stride
 		command = commandEncodeNRGBA
-	case *WEBP:
+	case *AnimatedImage:
 		// Animated WebP.
 		frames := v.GetFrames()
 		if len(frames) == 0 {
@@ -357,34 +363,69 @@ func convertToNRGBA(src image.Image) *image.NRGBA {
 	return dst
 }
 
-var _ himage.AnimatedImage = (*WEBP)(nil)
+var _ himage.AnimatedImage = (*AnimatedImage)(nil)
 
-// WEBP represents an animated WebP image.
+// AnimatedImage represents an animated WebP image.
 // The naming deliberately matches the fields in the standard library image/gif package.
-type WEBP struct {
+// This type is also used to preserve HDR color properties for single-frame images.
+type AnimatedImage struct {
 	image.Image    // The first frame.
 	frames         []image.Image
 	frameDurations []int
 	loopCount      int
+	depth          int // Bit depth per channel (8, 10, 12, 16). Used to preserve HDR quality.
+
+	// CICP color properties (for preserving color space in HDR images).
+	colorPrimaries          int
+	transferCharacteristics int
+	matrixCoefficients      int
+
+	// HDR CLLI (cd/m^2). Set when an AVIF gain map has been baked into PQ HDR.
+	maxCLL  int
+	maxPALL int
 }
 
-func (w *WEBP) GetLoopCount() int {
+func (w *AnimatedImage) GetLoopCount() int {
 	return w.loopCount
 }
 
-func (w *WEBP) GetFrames() []image.Image {
+func (w *AnimatedImage) GetDepth() int {
+	return w.depth
+}
+
+func (w *AnimatedImage) GetFrames() []image.Image {
 	return w.frames
 }
 
-func (w *WEBP) GetFrameDurations() []int {
+func (w *AnimatedImage) GetFrameDurations() []int {
 	return w.frameDurations
 }
 
-func (w *WEBP) GetRaw() any {
+func (w *AnimatedImage) GetRaw() any {
 	return w
 }
 
-func (w *WEBP) SetFrames(frames []image.Image) {
+func (w *AnimatedImage) GetColorPrimaries() int {
+	return w.colorPrimaries
+}
+
+func (w *AnimatedImage) GetTransferCharacteristics() int {
+	return w.transferCharacteristics
+}
+
+func (w *AnimatedImage) GetMatrixCoefficients() int {
+	return w.matrixCoefficients
+}
+
+func (w *AnimatedImage) GetMaxCLL() int {
+	return w.maxCLL
+}
+
+func (w *AnimatedImage) GetMaxPALL() int {
+	return w.maxPALL
+}
+
+func (w *AnimatedImage) SetFrames(frames []image.Image) {
 	if len(frames) == 0 {
 		panic("frames cannot be empty")
 	}
@@ -392,6 +433,6 @@ func (w *WEBP) SetFrames(frames []image.Image) {
 	w.Image = frames[0]
 }
 
-func (w *WEBP) SetWidthHeight(width, height int) {
-	// No-op for WEBP.
+func (w *AnimatedImage) SetWidthHeight(width, height int) {
+	// No-op for AnimatedImage.
 }

resources/images/codec.go

@@ -15,6 +15,8 @@ package images
 
 import (
 	"bufio"
+	"bytes"
+	"encoding/binary"
 	"errors"
 	"fmt"
 	"image"
@@ -60,11 +62,12 @@ type EncodeDecoder interface {
 // Codec is a generic image codec supporting multiple formats.
 type Codec struct {
 	webp   EncodeDecoder
+	avif   EncodeDecoder
 	debugl logg.LevelLogger
 }
 
-func newCodec(webp EncodeDecoder, debugl logg.LevelLogger) *Codec {
-	return &Codec{webp: webp, debugl: debugl}
+func newCodec(webp, avif EncodeDecoder, debugl logg.LevelLogger) *Codec {
+	return &Codec{webp: webp, avif: avif, debugl: debugl}
 }
 
 func (d *Codec) EncodeTo(conf ImageConfig, w io.Writer, img image.Image) error {
@@ -136,6 +139,13 @@ func (d *Codec) EncodeTo(conf ImageConfig, w io.Writer, img image.Image) error {
 		return tiff.Encode(w, img, &tiff.Options{Compression: tiff.Deflate, Predictor: true})
 	case BMP:
 		return bmp.Encode(w, img)
+	case AVIF:
+		opts := map[string]any{
+			"compression":  conf.Compression,
+			"quality":      conf.Quality,
+			"encoderSpeed": conf.EncoderSpeed,
+		}
+		return d.avif.Encode(w, img, opts)
 	case WEBP:
 		// Convert bool to int because the C code reads it as a number.
 		useSharpYuvInt := 0
@@ -151,7 +161,7 @@ func (d *Codec) EncodeTo(conf ImageConfig, w io.Writer, img image.Image) error {
 		}
 		return d.webp.Encode(w, img, opts)
 	default:
-		return errors.New("format not supported")
+		return fmt.Errorf("format %q not supported", conf.TargetFormat)
 	}
 }
 
@@ -185,6 +195,8 @@ func (d *Codec) DecodeFormat(f Format, r io.Reader) (image.Image, error) {
 		return tiff.Decode(r)
 	case BMP:
 		return bmp.Decode(r)
+	case AVIF:
+		return d.avif.Decode(r)
 	case WEBP:
 		img, err := d.webp.Decode(r)
 		if err == nil {
@@ -296,6 +308,12 @@ const (
 	magicGif = "GIF8???"
 )
 
+var (
+	avifBrandAvis = []byte("avis")
+	avifBrandAvif = []byte("avif")
+	avifFtyp      = []byte("ftyp")
+)
+
 type magicFormat struct {
 	magic  string
 	format Format
@@ -308,7 +326,7 @@ var magicFormats = []magicFormat{
 
 // formatFromImage determines the image format from the magic bytes.
 // Note that this is only a partial implementation,
-// as we currently only need WebP and GIF detection.
+// as we currently only need WebP, GIF and AVIF detection.
 // The others can be handled by the standard library.
 func formatFromImage(r peekReader) (Format, error) {
 	for _, mf := range magicFormats {
@@ -318,9 +336,39 @@ func formatFromImage(r peekReader) (Format, error) {
 			return mf.format, nil
 		}
 	}
+	if isAvif(r) {
+		return AVIF, nil
+	}
 	return 0, nil
 }
 
+// isAvif reports whether r begins with an ISOBMFF ftyp box that identifies
+// the file as AVIF, either via the major brand ("avif"/"avis") or the
+// compatible brands list (e.g. major "mif1" with "avif" as a compatible brand).
+func isAvif(r peekReader) bool {
+	b, _ := r.Peek(12)
+	if len(b) < 12 || !bytes.Equal(b[4:8], avifFtyp) {
+		return false
+	}
+	if brand := b[8:12]; bytes.Equal(brand, avifBrandAvif) || bytes.Equal(brand, avifBrandAvis) {
+		return true
+	}
+	b, _ = r.Peek(64)
+	if len(b) < 16 {
+		return false
+	}
+	end := int(binary.BigEndian.Uint32(b[:4]))
+	if end < 16 || end > len(b) {
+		end = len(b)
+	}
+	for i := 16; i+4 <= end; i += 4 {
+		if brand := b[i : i+4]; bytes.Equal(brand, avifBrandAvif) || bytes.Equal(brand, avifBrandAvis) {
+			return true
+		}
+	}
+	return false
+}
+
 func match(magic string, b []byte) bool {
 	if len(magic) != len(b) {
 		return false

resources/images/config.go

@@ -71,6 +71,7 @@ var (
 		media.Builtin.BMPType.SubType:  BMP,
 		media.Builtin.GIFType.SubType:  GIF,
 		media.Builtin.WEBPType.SubType: WEBP,
+		media.Builtin.AVIFType.SubType: AVIF,
 	}
 
 	// We cannot process these formats, but we can provide metadata support for them (including width/height).
@@ -161,13 +162,14 @@ func ImageFormatFromMediaSubType(sub string) (Format, ImageResourceType) {
 }
 
 const (
-	defaultJPEGQuality     = 75
-	defaultResampleFilter  = "box"
-	defaultBgColor         = "#ffffff"
-	defaultHint            = "photo"
-	defaultCompression     = "lossy"
-	defaultWebpUseSharpYuv = false
-	defaultWebpMethod      = 2
+	defaultJPEGQuality      = 75
+	defaultResampleFilter   = "box"
+	defaultBgColor          = "#ffffff"
+	defaultHint             = "photo"
+	defaultCompression      = "lossy"
+	defaultWebpUseSharpYuv  = false
+	defaultWebpMethod       = 2
+	defaultAvifEncoderSpeed = 10
 )
 
 var (
@@ -181,6 +183,9 @@ var (
 			"useSharpYuv": defaultWebpUseSharpYuv,
 			"method":      defaultWebpMethod,
 		},
+		"avif": map[string]any{
+			"encoderSpeed": defaultAvifEncoderSpeed,
+		},
 	}
 
 	defaultImageConfig *config.ConfigNamespace[ImagingConfig, ImagingConfigInternal]
@@ -212,6 +217,11 @@ func DecodeConfig(in map[string]any) (*config.ConfigNamespace[ImagingConfig, Ima
 			hmaps.MergeShallow(webp, defaultImaging["webp"].(map[string]any))
 		}
 
+		// Deep merge avif defaults.
+		if avif, ok := m["avif"].(map[string]any); ok {
+			hmaps.MergeShallow(avif, defaultImaging["avif"].(map[string]any))
+		}
+
 		var i ImagingConfigInternal
 		if err := mapstructure.Decode(m, &i.Imaging); err != nil {
 			return i, nil, err
@@ -279,6 +289,8 @@ func DecodeImageConfig(options []string, defaults *config.ConfigNamespace[Imagin
 			c.Hint = part
 		} else if _, ok := compressionMethods[part]; ok {
 			c.Compression = part
+		} else if f, ok := ImageFormatFromExt("." + part); ok {
+			c.TargetFormat = f
 		} else if part[0] == '#' {
 			c.BgColor, err = hexStringToColorGo(part[1:])
 			if err != nil {
@@ -320,8 +332,6 @@ func DecodeImageConfig(options []string, defaults *config.ConfigNamespace[Imagin
 			} else {
 				return c, errors.New("invalid image dimensions")
 			}
-		} else if f, ok := ImageFormatFromExt("." + part); ok {
-			c.TargetFormat = f
 		}
 	}
 
@@ -424,6 +434,9 @@ type ImageConfig struct {
 	UseSharpYuv bool
 	Method      int
 
+	// AVIF-specific options.
+	EncoderSpeed int
+
 	Width  int
 	Height int
 
@@ -478,7 +491,7 @@ type ImagingConfig struct {
 
 	// Compression method to use.
 	// One of "lossy" or "lossless".
-	// Note that lossless is currently only supported for WebP.
+	// Note that lossless is currently only supported for WebP and AVIF.
 	Compression string
 
 	// Resample filter to use in resize operations.
@@ -500,6 +513,7 @@ type ImagingConfig struct {
 	Exif ExifConfig
 	Meta MetaConfig
 	Webp WebpConfig
+	Avif AvifConfig
 }
 
 var validMetaSources = map[string]bool{
@@ -571,6 +585,13 @@ func (cfg *ImagingConfig) init() error {
 		return fmt.Errorf("webp method must be between 0 and 6, got %d", cfg.Webp.Method)
 	}
 
+	if cfg.Avif.EncoderSpeed == 0 {
+		cfg.Avif.EncoderSpeed = defaultAvifEncoderSpeed
+	}
+	if cfg.Avif.EncoderSpeed < 1 || cfg.Avif.EncoderSpeed > 10 {
+		return fmt.Errorf("avif encoderSpeed must be between 1 and 10, got %d", cfg.Avif.EncoderSpeed)
+	}
+
 	return nil
 }
 
@@ -610,6 +631,19 @@ type MetaConfig struct {
 	Sources []string
 }
 
+// AvifConfig holds AVIF-specific encoding configuration.
+type AvifConfig struct {
+	// Encoder quality/speed trade-off, 1 (slowest, best quality / smallest
+	// files) to 10 (fastest). Default is 10 — fast enough for incremental
+	// builds with quality indistinguishable from slower settings at typical
+	// web thumbnail sizes. Lower values reduce file size at the cost of
+	// build time.
+	// We recommend sticking with the default of 10 unless you have a specific reason to change it,
+	// and to stay above 5 to avoid very long build times and timeouts.
+	// 0 is treated as unset and falls back to the default.
+	EncoderSpeed int
+}
+
 // WebpConfig holds WebP-specific encoding configuration.
 type WebpConfig struct {
 	// Hint about what type of image this is.

resources/images/config_test.go

@@ -76,6 +76,37 @@ func TestDecodeConfig(t *testing.T) {
 	conf = imagingConfig.Config
 	c.Assert(conf.Imaging.Exif.DisableLatLong, qt.Equals, true)
 	c.Assert(conf.Imaging.Exif.ExcludeFields, qt.Equals, "GPS|Exif|Exposure[M|P|B]|Contrast|Resolution|Sharp|JPEG|Metering|Sensing|Saturation|ColorSpace|Flash|WhiteBalance")
+
+	// AVIF: default is speed 10.
+	imagingConfig, err = DecodeConfig(map[string]any{})
+	c.Assert(err, qt.IsNil)
+	c.Assert(imagingConfig.Config.Imaging.Avif.EncoderSpeed, qt.Equals, defaultAvifEncoderSpeed)
+
+	// AVIF: override via config.
+	imagingConfig, err = DecodeConfig(map[string]any{
+		"avif": map[string]any{"encoderSpeed": 5},
+	})
+	c.Assert(err, qt.IsNil)
+	c.Assert(imagingConfig.Config.Imaging.Avif.EncoderSpeed, qt.Equals, 5)
+
+	// AVIF: out-of-range rejected.
+	_, err = DecodeConfig(map[string]any{
+		"avif": map[string]any{"encoderSpeed": 11},
+	})
+	c.Assert(err, qt.ErrorMatches, ".*encoderSpeed must be between.*")
+
+	// AVIF: minimum is 1; 0 is treated as unset and falls back to the default.
+	imagingConfig, err = DecodeConfig(map[string]any{
+		"avif": map[string]any{"encoderSpeed": 0},
+	})
+	c.Assert(err, qt.IsNil)
+	c.Assert(imagingConfig.Config.Imaging.Avif.EncoderSpeed, qt.Equals, defaultAvifEncoderSpeed)
+
+	imagingConfig, err = DecodeConfig(map[string]any{
+		"avif": map[string]any{"encoderSpeed": 1},
+	})
+	c.Assert(err, qt.IsNil)
+	c.Assert(imagingConfig.Config.Imaging.Avif.EncoderSpeed, qt.Equals, 1)
 }
 
 func TestDecodeImageConfig(t *testing.T) {

resources/images/image.go

@@ -99,7 +99,7 @@ func (i *Image) InitConfig(r io.Reader) error {
 	return err
 }
 
-func (i *Image) initConfig() error {
+func (i *Image) initConfig() {
 	var err error
 	i.configInit.Do(func() {
 		if i.configLoaded {
@@ -118,10 +118,8 @@ func (i *Image) initConfig() error {
 	})
 
 	if err != nil {
-		return fmt.Errorf("failed to load image config: %w", err)
+		panic(fmt.Errorf("failed to load image config: %w", err))
 	}
-
-	return nil
 }
 
 func NewImageProcessor(debugl, warnl logg.LevelLogger, wasmDispatchers *warpc.Dispatchers, cfg *config.ConfigNamespace[ImagingConfig, ImagingConfigInternal]) (*ImageProcessor, error) {
@@ -154,7 +152,11 @@ func NewImageProcessor(debugl, warnl logg.LevelLogger, wasmDispatchers *warpc.Di
 	if webpCodec == nil {
 		return nil, errors.New("webp codec is not available")
 	}
-	imageCodec := newCodec(webpCodec, debugl)
+	avifCodec, err := wasmDispatchers.NewAvifCodec()
+	if err != nil {
+		return nil, err
+	}
+	imageCodec := newCodec(webpCodec, avifCodec, debugl)
 
 	return &ImageProcessor{
 		Cfg:         cfg,
@@ -256,7 +258,12 @@ func (p *ImageProcessor) resolveSrc(src image.Image, targetFormat Format) image.
 	if animatedImage, ok := src.(himage.AnimatedImage); ok {
 		frames := animatedImage.GetFrames()
 		// If e.g. converting an animated GIF to JPEG, we only want the first frame.
-		if len(frames) < 2 || !targetFormat.SupportsAnimation() {
+		// Preserve the AnimatedImage wrapper for color properties only when there is
+		// no actual animation to preserve. Multi-frame animated sources must still be
+		// collapsed unless the target format supports animation output.
+		shouldExtractFirstFrame := len(frames) < 2 || !targetFormat.SupportsAnimation()
+		colorPropsNeedPreserving := himage.HasColorProperties(src) && len(frames) < 2
+		if shouldExtractFirstFrame && !colorPropsNeedPreserving {
 			src = frames[0]
 		}
 	}
@@ -268,20 +275,36 @@ func (p *ImageProcessor) doFilter(src image.Image, targetFormat Format, filters
 
 	if anim, ok := src.(himage.AnimatedImage); ok {
 		frames := anim.GetFrames()
-		if len(frames) < 2 || !targetFormat.SupportsAnimation() {
+		// Check if we should extract first frame or preserve AnimatedImage wrapper.
+		// Preserve AnimatedImage if color properties need to be maintained.
+		shouldExtractFirstFrame := len(frames) < 2 || !targetFormat.SupportsAnimation()
+		colorPropsNeedPreserving := himage.HasColorProperties(src) && len(frames) < 2
+		if shouldExtractFirstFrame && !colorPropsNeedPreserving {
 			src = frames[0]
 		} else {
 			var bounds image.Rectangle
 			firstFrame := frames[0]
-			tmp := image.NewNRGBA(firstFrame.Bounds())
+			// Preserve bit depth for HDR images.
+			var tmp draw.Image
+			switch firstFrame.(type) {
+			case *image.RGBA64, *image.NRGBA64:
+				tmp = image.NewNRGBA64(firstFrame.Bounds())
+			default:
+				tmp = image.NewNRGBA(firstFrame.Bounds())
+			}
 			for i, frame := range frames {
 				gift.New().DrawAt(tmp, frame, frame.Bounds().Min, gift.OverOperator)
 				bounds = filter.Bounds(tmp.Bounds())
 				var dst draw.Image
-				if paletted, ok := frame.(*image.Paletted); ok {
+				switch f := frame.(type) {
+				case *image.Paletted:
 					// Gif.
-					dst = image.NewPaletted(bounds, paletted.Palette)
-				} else {
+					dst = image.NewPaletted(bounds, f.Palette)
+				case *image.RGBA64:
+					dst = image.NewRGBA64(bounds)
+				case *image.NRGBA64:
+					dst = image.NewNRGBA64(bounds)
+				default:
 					dst = image.NewNRGBA(bounds)
 				}
 				filter.Draw(dst, tmp)
@@ -305,6 +328,12 @@ func (p *ImageProcessor) doFilter(src image.Image, targetFormat Format, filters
 		dst = image.NewNRGBA(bounds)
 	case *image.Gray:
 		dst = image.NewGray(bounds)
+	case *image.RGBA64:
+		dst = image.NewRGBA64(bounds)
+	case *image.NRGBA64:
+		dst = image.NewNRGBA64(bounds)
+	case *image.Gray16:
+		dst = image.NewGray16(bounds)
 	default:
 		dst = image.NewNRGBA(bounds)
 	}
@@ -318,12 +347,13 @@ func GetDefaultImageConfig(defaults *config.ConfigNamespace[ImagingConfig, Imagi
 		defaults = defaultImageConfig
 	}
 	return ImageConfig{
-		Anchor:      -1, // The real values start at 0.
-		Hint:        defaults.Config.Imaging.Webp.Hint,
-		Quality:     defaults.Config.Imaging.Quality,
-		Compression: defaults.Config.Imaging.Compression,
-		UseSharpYuv: defaults.Config.Imaging.Webp.UseSharpYuv,
-		Method:      defaults.Config.Imaging.Webp.Method,
+		Anchor:       -1, // The real values start at 0.
+		Hint:         defaults.Config.Imaging.Webp.Hint,
+		Quality:      defaults.Config.Imaging.Quality,
+		Compression:  defaults.Config.Imaging.Compression,
+		UseSharpYuv:  defaults.Config.Imaging.Webp.UseSharpYuv,
+		Method:       defaults.Config.Imaging.Webp.Method,
+		EncoderSpeed: defaults.Config.Imaging.Avif.EncoderSpeed,
 	}
 }
 
@@ -342,9 +372,9 @@ const (
 	TIFF
 	BMP
 	WEBP
+	AVIF
 
 	// Below: We have no encoder/decoder for these, but we can provide metadata support for them (including width/height).
-	AVIF
 	HEIF
 	HEIC
 )
@@ -387,6 +417,9 @@ func (f Format) SupportsTransparency() bool {
 }
 
 // SupportsAnimation reports whether the format supports animation.
+// AVIF supports animation in the spec, but Hugo's AVIF encoder is single-frame
+// only — including AVIF here would make the pipeline preserve frames just to
+// drop them at encode time.
 func (f Format) SupportsAnimation() bool {
 	return f == GIF || f == WEBP
 }

resources/images/images_golden_integration_test.go

@@ -336,6 +336,91 @@ Home.
 {{ template "process" (dict "spec" "resize 300x300 jpg #b31280" "img" $gopher) }}
 
 
+` + goldenProcess
+
+	opts := imagetesting.DefaultGoldenOpts
+	opts.T = t
+	opts.Name = name
+	opts.Files = files
+
+	imagetesting.RunGolden(opts)
+}
+
+func TestImagesGoldenProcessAvif(t *testing.T) {
+	t.Parallel()
+
+	if imagetesting.SkipGoldenTests {
+		t.Skip("Skip golden test on this architecture")
+	}
+
+	// Will be used as the base folder for generated images.
+	name := "process/avif"
+
+	files := `
+-- hugo.toml --
+-- assets/anim.webp --
+sourcefilename: ../testdata/webp/anim.webp
+-- assets/dock.avif --
+sourcefilename: ../testdata/bep/dock-75-hdr.avif
+-- assets/sunset420.avif --
+sourcefilename: ../testdata/sunset_420.avif
+-- assets/sunset.jpg --
+sourcefilename: ../testdata/sunset.jpg
+-- assets/giphy.avif --
+sourcefilename: ../testdata/giphy.avif
+-- assets/fuzzycircle.webp --
+sourcefilename: ../testdata/webp/fuzzy-cirlcle-transparent-32.webp
+-- layouts/home.html --
+Home.
+{{ $sunset := resources.Get "sunset.jpg" }}
+{{ $dock := resources.Get "dock.avif" }}
+{{ $sunset420 := resources.Get "sunset420.avif" }}
+{{ $webpAnim := resources.Get "anim.webp" }}
+{{ $giphy := resources.Get "giphy.avif" }}
+{{ $fuzzyCircle := resources.Get "fuzzycircle.webp" }}
+
+{{ template "process" (dict "spec" "r1" "img" $dock) }}
+{{ template "process" (dict "spec" "q50" "img" $dock) }}
+{{ template "process" (dict "spec" "r2" "img" $sunset420) }}
+{{ template "process" (dict "spec" "avif" "img" $webpAnim) }}
+{{ template "process" (dict "spec" "gif" "img" $giphy) }}
+{{ template "process" (dict "spec" "crop 300x300 smart avif" "img" $fuzzyCircle) }}
+{{ template "process" (dict "spec" "crop 300x300 smart #ff9999 avif" "img" $fuzzyCircle) }}
+
+
+
+
+
+` + goldenProcess
+
+	opts := imagetesting.DefaultGoldenOpts
+	opts.T = t
+	opts.Name = name
+	opts.Files = files
+
+	imagetesting.RunGolden(opts)
+}
+
+func TestImagesGoldenProcessAviStraws(t *testing.T) {
+	t.Parallel()
+
+	if imagetesting.SkipGoldenTests {
+		t.Skip("Skip golden test on this architecture")
+	}
+
+	// Will be used as the base folder for generated images.
+	name := "process/avifstraws"
+
+	files := `
+-- hugo.toml --
+-- assets/straws.avif --
+sourcefilename: ../testdata/bep/straws.avif
+-- layouts/home.html --
+Home.
+{{ $straws := resources.Get "straws.avif" }}
+{{ template "process" (dict "spec" "resize 900x" "img" $straws) }}
+
+
 ` + goldenProcess
 
 	opts := imagetesting.DefaultGoldenOpts

resources/images/meta/meta_integration_test.go

@@ -294,7 +294,7 @@ $ic.Width/Height: 900x562
 
 IsImageResource AVIF: true
 IsImageResourceWithMeta AVIF: true
-IsImageResourceProcessable AVIF: false
+IsImageResourceProcessable AVIF: true
 Has width AVIF: true
 Has meta AVIF: true
 

resources/testdata/bep/license.txt

@@ -0,0 +1 @@
+All images in this folder are copyrighted Bjørn Erik Pedersen (2026), Creative Commons Attribution-Share Alike 4.0 International license.