Add AV1 video codec support

This commit adds support for AV1 video decoding in lilliput, following
the same pattern as HEVC support with build flag gating.

Changes:
- Add AV1 decoder enablement behind build flag (av1Enabled)
- Update FFmpeg build scripts to include --enable-decoder=av1 and --enable-libaom
- Add codec gating logic to reject AV1 when disabled (default)
- Add basic tests for AV1 support and decoder creation
- Include test AV1 video file for validation

Usage:
Enable AV1 support: go build -ldflags="-X=github.com/discord/lilliput.av1Enabled=true"

Features:
- AV1 video detection in containers (MP4, WebM, etc.)
- First-frame extraction from AV1 videos
- Same security model as HEVC (disabled by default)

Author: skidder

avcodec.cpp

@@ -154,7 +154,7 @@ bool avcodec_decoder_is_streamable(const opencv_mat mat)
     return false;
 }
 
-avcodec_decoder avcodec_decoder_create(const opencv_mat buf, const bool hevc_enabled)
+avcodec_decoder avcodec_decoder_create(const opencv_mat buf, const bool hevc_enabled, const bool av1_enabled)
 {
     avcodec_decoder d = new struct avcodec_decoder_struct();
     memset(d, 0, sizeof(struct avcodec_decoder_struct));
@@ -238,6 +238,11 @@ avcodec_decoder avcodec_decoder_create(const opencv_mat buf, const bool hevc_ena
         return NULL;
     }
 
+    if (codec->id == AV_CODEC_ID_AV1 && !av1_enabled) {
+        avcodec_decoder_release(d);
+        return NULL;
+    }
+
     d->codec = avcodec_alloc_context3(codec);
 
     res = avcodec_parameters_to_context(d->codec, codec_params);

avcodec.go

@@ -16,6 +16,10 @@ const atomHeaderSize = 8
 // Enable by building/running with "-ldflags=-X=github.com/discord/lilliput.hevcEnabled=true"
 var hevcEnabled string
 
+// Set AV1 decoder enablement behind a build flag, defaults to off
+// Enable by building/running with "-ldflags=-X=github.com/discord/lilliput.av1Enabled=true"
+var av1Enabled string
+
 // avCodecDecoder handles decoding of various video/image formats using FFmpeg's avcodec.
 type avCodecDecoder struct {
 	decoder      C.avcodec_decoder
@@ -35,7 +39,7 @@ func newAVCodecDecoder(buf []byte) (*avCodecDecoder, error) {
 		return nil, ErrBufTooSmall
 	}
 
-	decoder := C.avcodec_decoder_create(mat, hevcEnabled == "true")
+	decoder := C.avcodec_decoder_create(mat, hevcEnabled == "true", av1Enabled == "true")
 	if decoder == nil {
 		C.opencv_mat_release(mat)
 		return nil, ErrInvalidImage

avcodec.hpp

@@ -11,7 +11,7 @@ typedef struct avcodec_decoder_struct* avcodec_decoder;
 
 void avcodec_init();
 
-avcodec_decoder avcodec_decoder_create(const opencv_mat buf, const bool hevc_enabled);
+avcodec_decoder avcodec_decoder_create(const opencv_mat buf, const bool hevc_enabled, const bool av1_enabled);
 void avcodec_decoder_release(avcodec_decoder d);
 int avcodec_decoder_get_width(const avcodec_decoder d);
 int avcodec_decoder_get_height(const avcodec_decoder d);

avcodec_test.go

@@ -59,6 +59,65 @@ func TestICCProfile(t *testing.T) {
 	}
 }
 
+func TestAV1Support(t *testing.T) {
+	// Test that AV1 variables are properly defined
+	if av1Enabled != "true" && av1Enabled != "" {
+		// This should be empty by default, confirming our variable is defined
+		t.Logf("AV1 support is disabled (expected): %q", av1Enabled)
+	}
+}
+
+func TestAV1VideoDecoding(t *testing.T) {
+	// Test AV1 video file
+	av1Mp4, err := os.ReadFile("testdata/av1-mp4.mp4")
+	if err != nil {
+		t.Fatalf("failed to open AV1 test file: %v", err)
+	}
+
+	t.Run("AV1_Disabled_By_Default", func(t *testing.T) {
+		// Should fail when AV1 is disabled (default)
+		_, err := newAVCodecDecoder(av1Mp4)
+		if err == nil {
+			t.Logf("AV1 decoder created successfully with av1Enabled=%q", av1Enabled)
+		} else {
+			t.Logf("AV1 decoder failed as expected when disabled: %v", err)
+		}
+	})
+
+	// Note: Testing with AV1 enabled requires building with the flag:
+	// go test -ldflags="-X=github.com/discord/lilliput.av1Enabled=true"
+	if av1Enabled == "true" {
+		t.Run("AV1_Enabled_Decoding", func(t *testing.T) {
+			decoder, err := newAVCodecDecoder(av1Mp4)
+			if err != nil {
+				t.Fatalf("failed to create AV1 decoder: %v", err)
+			}
+			defer decoder.Close()
+
+			// Test basic metadata
+			header, err := decoder.Header()
+			if err != nil {
+				t.Fatalf("failed to get AV1 header: %v", err)
+			}
+
+			t.Logf("AV1 video dimensions: %dx%d", header.Width(), header.Height())
+			t.Logf("AV1 video duration: %v", decoder.Duration())
+			t.Logf("AV1 video description: %s", decoder.Description())
+
+			// Test first frame extraction
+			framebuffer := NewFramebuffer(header.Width(), header.Height())
+			defer framebuffer.Close()
+
+			err = decoder.DecodeTo(framebuffer)
+			if err != nil {
+				t.Fatalf("failed to decode AV1 first frame: %v", err)
+			}
+
+			t.Log("Successfully extracted first frame from AV1 video")
+		})
+	}
+}
+
 func BenchmarkIsStreamableWebMp4(b *testing.B) {
 	// Read the web-optimized streamable MP4 file
 	webMp4, err := os.ReadFile("testdata/big_buck_bunny_480p_10s_web.mp4")

deps/build-deps-linux.sh

@@ -343,10 +343,12 @@ $BASEDIR/ffmpeg/configure $FFMPEG_CROSS_COMPILE_FLAGS \
     --enable-decoder=hevc \
     --enable-decoder=vp9 \
     --enable-decoder=vp8 \
+    --enable-decoder=av1 \
     --enable-decoder=flac \
     --enable-decoder=mp3 \
     --enable-decoder=aac \
     --enable-decoder=vorbis \
+    --enable-libaom \
     --disable-iconv \
     --disable-cuda \
     --disable-cuvid \

deps/build-deps-osx.sh

@@ -238,7 +238,7 @@ mkdir -p $BASEDIR/ffmpeg
 tar -xJf $SRCDIR/ffmpeg-7.0.2.orig.tar.xz -C $BASEDIR/ffmpeg --strip-components 1
 mkdir -p $BUILDDIR/ffmpeg
 cd $BUILDDIR/ffmpeg
-$BASEDIR/ffmpeg/configure --prefix=$PREFIX --disable-doc --disable-programs --disable-everything --enable-demuxer=mov --enable-demuxer=matroska --enable-demuxer=aac --enable-demuxer=flac --enable-demuxer=mp3 --enable-demuxer=ogg --enable-demuxer=wav --enable-decoder=mpeg4 --enable-decoder=h264 --enable-decoder=hevc --enable-decoder=vp9 --enable-decoder=vp8 --enable-decoder=flac --enable-decoder=mp3 --enable-decoder=aac --enable-decoder=vorbis --disable-iconv --arch=arm64 --enable-cross-compile --target-os=darwin
+$BASEDIR/ffmpeg/configure --prefix=$PREFIX --disable-doc --disable-programs --disable-everything --enable-demuxer=mov --enable-demuxer=matroska --enable-demuxer=aac --enable-demuxer=flac --enable-demuxer=mp3 --enable-demuxer=ogg --enable-demuxer=wav --enable-decoder=mpeg4 --enable-decoder=h264 --enable-decoder=hevc --enable-decoder=vp9 --enable-decoder=vp8 --enable-decoder=av1 --enable-decoder=flac --enable-decoder=mp3 --enable-decoder=aac --enable-decoder=vorbis --enable-libaom --disable-iconv --arch=arm64 --enable-cross-compile --target-os=darwin
 make
 make install