Source code
Revision control
Copy as Markdown
Other Tools
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "VPXDecoder.h"
#include <algorithm>
#include <vpx/vpx_image.h>
#include "BitReader.h"
#include "BitWriter.h"
#include "ImageContainer.h"
#include "TimeUnits.h"
#include "gfx2DGlue.h"
#include "gfxUtils.h"
#include "mozilla/PodOperations.h"
#include "mozilla/SyncRunnable.h"
#include "mozilla/TaskQueue.h"
#include "mozilla/Unused.h"
#include "nsError.h"
#include "PerformanceRecorder.h"
#include "prsystem.h"
#include "VideoUtils.h"
#undef LOG
#define LOG(arg, ...) \
DDMOZ_LOG(sPDMLog, mozilla::LogLevel::Debug, "::%s: " arg, __func__, \
##__VA_ARGS__)
namespace mozilla {
using namespace gfx;
using namespace layers;
static VPXDecoder::Codec MimeTypeToCodec(const nsACString& aMimeType) {
if (aMimeType.EqualsLiteral("video/vp8")) {
return VPXDecoder::Codec::VP8;
} else if (aMimeType.EqualsLiteral("video/vp9")) {
return VPXDecoder::Codec::VP9;
}
return VPXDecoder::Codec::Unknown;
}
static nsresult InitContext(vpx_codec_ctx_t* aCtx, const VideoInfo& aInfo,
const VPXDecoder::Codec aCodec, bool aLowLatency) {
int decode_threads = 2;
vpx_codec_iface_t* dx = nullptr;
if (aCodec == VPXDecoder::Codec::VP8) {
dx = vpx_codec_vp8_dx();
} else if (aCodec == VPXDecoder::Codec::VP9) {
dx = vpx_codec_vp9_dx();
if (aInfo.mDisplay.width >= 2048) {
decode_threads = 8;
} else if (aInfo.mDisplay.width >= 1024) {
decode_threads = 4;
}
}
decode_threads = std::min(decode_threads, PR_GetNumberOfProcessors());
vpx_codec_dec_cfg_t config;
config.threads = aLowLatency ? 1 : decode_threads;
config.w = config.h = 0; // set after decode
if (!dx || vpx_codec_dec_init(aCtx, dx, &config, 0)) {
return NS_ERROR_FAILURE;
}
return NS_OK;
}
VPXDecoder::VPXDecoder(const CreateDecoderParams& aParams)
: mImageContainer(aParams.mImageContainer),
mImageAllocator(aParams.mKnowsCompositor),
mTaskQueue(TaskQueue::Create(
GetMediaThreadPool(MediaThreadType::PLATFORM_DECODER), "VPXDecoder")),
mInfo(aParams.VideoConfig()),
mCodec(MimeTypeToCodec(aParams.VideoConfig().mMimeType)),
mLowLatency(
aParams.mOptions.contains(CreateDecoderParams::Option::LowLatency)),
mTrackingId(aParams.mTrackingId) {
MOZ_COUNT_CTOR(VPXDecoder);
PodZero(&mVPX);
PodZero(&mVPXAlpha);
}
VPXDecoder::~VPXDecoder() { MOZ_COUNT_DTOR(VPXDecoder); }
RefPtr<ShutdownPromise> VPXDecoder::Shutdown() {
RefPtr<VPXDecoder> self = this;
return InvokeAsync(mTaskQueue, __func__, [self]() {
vpx_codec_destroy(&self->mVPX);
vpx_codec_destroy(&self->mVPXAlpha);
return self->mTaskQueue->BeginShutdown();
});
}
RefPtr<MediaDataDecoder::InitPromise> VPXDecoder::Init() {
if (NS_FAILED(InitContext(&mVPX, mInfo, mCodec, mLowLatency))) {
return VPXDecoder::InitPromise::CreateAndReject(
NS_ERROR_DOM_MEDIA_FATAL_ERR, __func__);
}
if (mInfo.HasAlpha()) {
if (NS_FAILED(InitContext(&mVPXAlpha, mInfo, mCodec, mLowLatency))) {
return VPXDecoder::InitPromise::CreateAndReject(
NS_ERROR_DOM_MEDIA_FATAL_ERR, __func__);
}
}
return VPXDecoder::InitPromise::CreateAndResolve(TrackInfo::kVideoTrack,
__func__);
}
RefPtr<MediaDataDecoder::FlushPromise> VPXDecoder::Flush() {
return InvokeAsync(mTaskQueue, __func__, []() {
return FlushPromise::CreateAndResolve(true, __func__);
});
}
RefPtr<MediaDataDecoder::DecodePromise> VPXDecoder::ProcessDecode(
MediaRawData* aSample) {
MOZ_ASSERT(mTaskQueue->IsOnCurrentThread());
MediaInfoFlag flag = MediaInfoFlag::None;
flag |= (aSample->mKeyframe ? MediaInfoFlag::KeyFrame
: MediaInfoFlag::NonKeyFrame);
flag |= MediaInfoFlag::SoftwareDecoding;
switch (mCodec) {
case Codec::VP8:
flag |= MediaInfoFlag::VIDEO_VP8;
break;
case Codec::VP9:
flag |= MediaInfoFlag::VIDEO_VP9;
break;
default:
break;
}
flag |= MediaInfoFlag::VIDEO_THEORA;
auto rec = mTrackingId.map([&](const auto& aId) {
return PerformanceRecorder<DecodeStage>("VPXDecoder"_ns, aId, flag);
});
if (vpx_codec_err_t r = vpx_codec_decode(&mVPX, aSample->Data(),
aSample->Size(), nullptr, 0)) {
LOG("VPX Decode error: %s", vpx_codec_err_to_string(r));
return DecodePromise::CreateAndReject(
MediaResult(NS_ERROR_DOM_MEDIA_DECODE_ERR,
RESULT_DETAIL("VPX error: %s", vpx_codec_err_to_string(r))),
__func__);
}
vpx_codec_iter_t iter = nullptr;
vpx_image_t* img;
vpx_image_t* img_alpha = nullptr;
bool alpha_decoded = false;
DecodedData results;
while ((img = vpx_codec_get_frame(&mVPX, &iter))) {
NS_ASSERTION(img->fmt == VPX_IMG_FMT_I420 || img->fmt == VPX_IMG_FMT_I444,
"WebM image format not I420 or I444");
NS_ASSERTION(!alpha_decoded,
"Multiple frames per packet that contains alpha");
if (aSample->AlphaSize() > 0) {
if (!alpha_decoded) {
MediaResult rv = DecodeAlpha(&img_alpha, aSample);
if (NS_FAILED(rv)) {
return DecodePromise::CreateAndReject(rv, __func__);
}
alpha_decoded = true;
}
}
// Chroma shifts are rounded down as per the decoding examples in the SDK
VideoData::YCbCrBuffer b;
b.mPlanes[0].mData = img->planes[0];
b.mPlanes[0].mStride = img->stride[0];
b.mPlanes[0].mHeight = img->d_h;
b.mPlanes[0].mWidth = img->d_w;
b.mPlanes[0].mSkip = 0;
b.mPlanes[1].mData = img->planes[1];
b.mPlanes[1].mStride = img->stride[1];
b.mPlanes[1].mSkip = 0;
b.mPlanes[2].mData = img->planes[2];
b.mPlanes[2].mStride = img->stride[2];
b.mPlanes[2].mSkip = 0;
if (img->fmt == VPX_IMG_FMT_I420) {
b.mChromaSubsampling = gfx::ChromaSubsampling::HALF_WIDTH_AND_HEIGHT;
b.mPlanes[1].mHeight = (img->d_h + 1) >> img->y_chroma_shift;
b.mPlanes[1].mWidth = (img->d_w + 1) >> img->x_chroma_shift;
b.mPlanes[2].mHeight = (img->d_h + 1) >> img->y_chroma_shift;
b.mPlanes[2].mWidth = (img->d_w + 1) >> img->x_chroma_shift;
} else if (img->fmt == VPX_IMG_FMT_I444) {
b.mPlanes[1].mHeight = img->d_h;
b.mPlanes[1].mWidth = img->d_w;
b.mPlanes[2].mHeight = img->d_h;
b.mPlanes[2].mWidth = img->d_w;
} else {
LOG("VPX Unknown image format");
return DecodePromise::CreateAndReject(
MediaResult(NS_ERROR_DOM_MEDIA_DECODE_ERR,
RESULT_DETAIL("VPX Unknown image format")),
__func__);
}
b.mYUVColorSpace = [&]() {
switch (img->cs) {
case VPX_CS_BT_601:
case VPX_CS_SMPTE_170:
case VPX_CS_SMPTE_240:
return gfx::YUVColorSpace::BT601;
case VPX_CS_BT_709:
return gfx::YUVColorSpace::BT709;
case VPX_CS_BT_2020:
return gfx::YUVColorSpace::BT2020;
default:
return DefaultColorSpace({img->d_w, img->d_h});
}
}();
b.mColorRange = img->range == VPX_CR_FULL_RANGE ? gfx::ColorRange::FULL
: gfx::ColorRange::LIMITED;
RefPtr<VideoData> v;
if (!img_alpha) {
Result<already_AddRefed<VideoData>, MediaResult> r =
VideoData::CreateAndCopyData(
mInfo, mImageContainer, aSample->mOffset, aSample->mTime,
aSample->mDuration, b, aSample->mKeyframe, aSample->mTimecode,
mInfo.ScaledImageRect(img->d_w, img->d_h), mImageAllocator);
// TODO: Reject DecodePromise below with r's error return.
v = r.unwrapOr(nullptr);
} else {
VideoData::YCbCrBuffer::Plane alpha_plane;
alpha_plane.mData = img_alpha->planes[0];
alpha_plane.mStride = img_alpha->stride[0];
alpha_plane.mHeight = img_alpha->d_h;
alpha_plane.mWidth = img_alpha->d_w;
alpha_plane.mSkip = 0;
v = VideoData::CreateAndCopyData(
mInfo, mImageContainer, aSample->mOffset, aSample->mTime,
aSample->mDuration, b, alpha_plane, aSample->mKeyframe,
aSample->mTimecode, mInfo.ScaledImageRect(img->d_w, img->d_h));
}
if (!v) {
LOG("Image allocation error source %ux%u display %ux%u picture %ux%u",
img->d_w, img->d_h, mInfo.mDisplay.width, mInfo.mDisplay.height,
mInfo.mImage.width, mInfo.mImage.height);
return DecodePromise::CreateAndReject(
MediaResult(NS_ERROR_OUT_OF_MEMORY, __func__), __func__);
}
rec.apply([&](auto& aRec) {
return aRec.Record([&](DecodeStage& aStage) {
aStage.SetResolution(static_cast<int>(img->d_w),
static_cast<int>(img->d_h));
auto format = [&]() -> Maybe<DecodeStage::ImageFormat> {
switch (img->fmt) {
case VPX_IMG_FMT_I420:
return Some(DecodeStage::YUV420P);
case VPX_IMG_FMT_I444:
return Some(DecodeStage::YUV444P);
default:
return Nothing();
}
}();
format.apply([&](auto& aFmt) { aStage.SetImageFormat(aFmt); });
aStage.SetYUVColorSpace(b.mYUVColorSpace);
aStage.SetColorRange(b.mColorRange);
aStage.SetColorDepth(b.mColorDepth);
});
});
results.AppendElement(std::move(v));
}
return DecodePromise::CreateAndResolve(std::move(results), __func__);
}
RefPtr<MediaDataDecoder::DecodePromise> VPXDecoder::Decode(
MediaRawData* aSample) {
return InvokeAsync<MediaRawData*>(mTaskQueue, this, __func__,
&VPXDecoder::ProcessDecode, aSample);
}
RefPtr<MediaDataDecoder::DecodePromise> VPXDecoder::Drain() {
return InvokeAsync(mTaskQueue, __func__, [] {
return DecodePromise::CreateAndResolve(DecodedData(), __func__);
});
}
MediaResult VPXDecoder::DecodeAlpha(vpx_image_t** aImgAlpha,
const MediaRawData* aSample) {
vpx_codec_err_t r = vpx_codec_decode(&mVPXAlpha, aSample->AlphaData(),
aSample->AlphaSize(), nullptr, 0);
if (r) {
LOG("VPX decode alpha error: %s", vpx_codec_err_to_string(r));
return MediaResult(NS_ERROR_DOM_MEDIA_DECODE_ERR,
RESULT_DETAIL("VPX decode alpha error: %s",
vpx_codec_err_to_string(r)));
}
vpx_codec_iter_t iter = nullptr;
*aImgAlpha = vpx_codec_get_frame(&mVPXAlpha, &iter);
NS_ASSERTION((*aImgAlpha)->fmt == VPX_IMG_FMT_I420 ||
(*aImgAlpha)->fmt == VPX_IMG_FMT_I444,
"WebM image format not I420 or I444");
return NS_OK;
}
nsCString VPXDecoder::GetCodecName() const {
switch (mCodec) {
case Codec::VP8:
return "vp8"_ns;
case Codec::VP9:
return "vp9"_ns;
default:
return "unknown"_ns;
}
}
/* static */
bool VPXDecoder::IsVPX(const nsACString& aMimeType, uint8_t aCodecMask) {
return ((aCodecMask & VPXDecoder::VP8) &&
aMimeType.EqualsLiteral("video/vp8")) ||
((aCodecMask & VPXDecoder::VP9) &&
aMimeType.EqualsLiteral("video/vp9"));
}
/* static */
bool VPXDecoder::IsVP8(const nsACString& aMimeType) {
return IsVPX(aMimeType, VPXDecoder::VP8);
}
/* static */
bool VPXDecoder::IsVP9(const nsACString& aMimeType) {
return IsVPX(aMimeType, VPXDecoder::VP9);
}
/* static */
bool VPXDecoder::IsKeyframe(Span<const uint8_t> aBuffer, Codec aCodec) {
VPXStreamInfo info;
return GetStreamInfo(aBuffer, info, aCodec) && info.mKeyFrame;
}
/* static */
gfx::IntSize VPXDecoder::GetFrameSize(Span<const uint8_t> aBuffer,
Codec aCodec) {
VPXStreamInfo info;
if (!GetStreamInfo(aBuffer, info, aCodec)) {
return gfx::IntSize();
}
return info.mImage;
}
/* static */
gfx::IntSize VPXDecoder::GetDisplaySize(Span<const uint8_t> aBuffer,
Codec aCodec) {
VPXStreamInfo info;
if (!GetStreamInfo(aBuffer, info, aCodec)) {
return gfx::IntSize();
}
return info.mDisplay;
}
/* static */
int VPXDecoder::GetVP9Profile(Span<const uint8_t> aBuffer) {
VPXStreamInfo info;
if (!GetStreamInfo(aBuffer, info, Codec::VP9)) {
return -1;
}
return info.mProfile;
}
/* static */
bool VPXDecoder::GetStreamInfo(Span<const uint8_t> aBuffer,
VPXDecoder::VPXStreamInfo& aInfo, Codec aCodec) {
if (aBuffer.IsEmpty()) {
// Can't be good.
return false;
}
aInfo = VPXStreamInfo();
if (aCodec == Codec::VP8) {
aInfo.mKeyFrame = (aBuffer[0] & 1) ==
0; // frame type (0 for key frames, 1 for interframes)
if (!aInfo.mKeyFrame) {
// We can't retrieve the required information from interframes.
return true;
}
if (aBuffer.Length() < 10) {
return false;
}
uint8_t version = (aBuffer[0] >> 1) & 0x7;
if (version > 3) {
return false;
}
uint8_t start_code_byte_0 = aBuffer[3];
uint8_t start_code_byte_1 = aBuffer[4];
uint8_t start_code_byte_2 = aBuffer[5];
if (start_code_byte_0 != 0x9d || start_code_byte_1 != 0x01 ||
start_code_byte_2 != 0x2a) {
return false;
}
uint16_t width = (aBuffer[6] | aBuffer[7] << 8) & 0x3fff;
uint16_t height = (aBuffer[8] | aBuffer[9] << 8) & 0x3fff;
// aspect ratio isn't found in the VP8 frame header.
aInfo.mImage = gfx::IntSize(width, height);
aInfo.mDisplayAndImageDifferent = false;
aInfo.mDisplay = aInfo.mImage;
return true;
}
BitReader br(aBuffer.Elements(), aBuffer.Length() * 8);
uint32_t frameMarker = br.ReadBits(2); // frame_marker
if (frameMarker != 2) {
// That's not a valid vp9 header.
return false;
}
uint32_t profile = br.ReadBits(1); // profile_low_bit
profile |= br.ReadBits(1) << 1; // profile_high_bit
if (profile == 3) {
profile += br.ReadBits(1); // reserved_zero
if (profile > 3) {
// reserved_zero wasn't zero.
return false;
}
}
aInfo.mProfile = profile;
bool show_existing_frame = br.ReadBits(1);
if (show_existing_frame) {
if (profile == 3 && aBuffer.Length() < 2) {
return false;
}
Unused << br.ReadBits(3); // frame_to_show_map_idx
return true;
}
if (aBuffer.Length() < 10) {
// Header too small;
return false;
}
aInfo.mKeyFrame = !br.ReadBits(1);
bool show_frame = br.ReadBits(1);
bool error_resilient_mode = br.ReadBits(1);
auto frame_sync_code = [&]() -> bool {
uint8_t frame_sync_byte_1 = br.ReadBits(8);
uint8_t frame_sync_byte_2 = br.ReadBits(8);
uint8_t frame_sync_byte_3 = br.ReadBits(8);
return frame_sync_byte_1 == 0x49 && frame_sync_byte_2 == 0x83 &&
frame_sync_byte_3 == 0x42;
};
auto color_config = [&]() -> bool {
aInfo.mBitDepth = 8;
if (profile >= 2) {
bool ten_or_twelve_bit = br.ReadBits(1);
aInfo.mBitDepth = ten_or_twelve_bit ? 12 : 10;
}
aInfo.mColorSpace = br.ReadBits(3);
if (aInfo.mColorSpace != 7 /* CS_RGB */) {
aInfo.mFullRange = br.ReadBits(1);
if (profile == 1 || profile == 3) {
aInfo.mSubSampling_x = br.ReadBits(1);
aInfo.mSubSampling_y = br.ReadBits(1);
if (br.ReadBits(1)) { // reserved_zero
return false;
};
} else {
aInfo.mSubSampling_x = true;
aInfo.mSubSampling_y = true;
}
} else {
aInfo.mFullRange = true;
if (profile == 1 || profile == 3) {
aInfo.mSubSampling_x = false;
aInfo.mSubSampling_y = false;
if (br.ReadBits(1)) { // reserved_zero
return false;
};
} else {
// sRGB color space is only available with VP9 profile 1.
return false;
}
}
return true;
};
auto frame_size = [&]() {
int32_t width = static_cast<int32_t>(br.ReadBits(16)) + 1;
int32_t height = static_cast<int32_t>(br.ReadBits(16)) + 1;
aInfo.mImage = gfx::IntSize(width, height);
};
auto render_size = [&]() {
// render_and_frame_size_different
aInfo.mDisplayAndImageDifferent = br.ReadBits(1);
if (aInfo.mDisplayAndImageDifferent) {
int32_t width = static_cast<int32_t>(br.ReadBits(16)) + 1;
int32_t height = static_cast<int32_t>(br.ReadBits(16)) + 1;
aInfo.mDisplay = gfx::IntSize(width, height);
} else {
aInfo.mDisplay = aInfo.mImage;
}
};
if (aInfo.mKeyFrame) {
if (!frame_sync_code()) {
return false;
}
if (!color_config()) {
return false;
}
frame_size();
render_size();
} else {
bool intra_only = show_frame ? false : br.ReadBit();
if (!error_resilient_mode) {
Unused << br.ReadBits(2); // reset_frame_context
}
if (intra_only) {
if (!frame_sync_code()) {
return false;
}
if (profile > 0) {
if (!color_config()) {
return false;
}
} else {
aInfo.mColorSpace = 1; // CS_BT_601
aInfo.mSubSampling_x = true;
aInfo.mSubSampling_y = true;
aInfo.mBitDepth = 8;
}
Unused << br.ReadBits(8); // refresh_frame_flags
frame_size();
render_size();
}
}
return true;
}
// Ref: "VP Codec ISO Media File Format Binding, v1.0, 2017-03-31"
//
// class VPCodecConfigurationBox extends FullBox('vpcC', version = 1, 0)
// {
// VPCodecConfigurationRecord() vpcConfig;
// }
//
// aligned (8) class VPCodecConfigurationRecord {
// unsigned int (8) profile;
// unsigned int (8) level;
// unsigned int (4) bitDepth;
// unsigned int (3) chromaSubsampling;
// unsigned int (1) videoFullRangeFlag;
// unsigned int (8) colourPrimaries;
// unsigned int (8) transferCharacteristics;
// unsigned int (8) matrixCoefficients;
// unsigned int (16) codecIntializationDataSize;
// unsigned int (8)[] codecIntializationData;
// }
/* static */
void VPXDecoder::GetVPCCBox(MediaByteBuffer* aDestBox,
const VPXStreamInfo& aInfo) {
BitWriter writer(aDestBox);
int chroma = [&]() {
if (aInfo.mSubSampling_x && aInfo.mSubSampling_y) {
return 1; // 420 Colocated;
}
if (aInfo.mSubSampling_x && !aInfo.mSubSampling_y) {
return 2; // 422
}
if (!aInfo.mSubSampling_x && !aInfo.mSubSampling_y) {
return 3; // 444
}
// This indicates 4:4:0 subsampling, which is not expressable in the
// 'vpcC' box. Default to 4:2:0.
return 1;
}();
writer.WriteU8(1); // version
writer.WriteBits(0, 24); // flags
writer.WriteU8(aInfo.mProfile); // profile
writer.WriteU8(10); // level set it to 1.0
writer.WriteBits(aInfo.mBitDepth, 4); // bitdepth
writer.WriteBits(chroma, 3); // chroma
writer.WriteBit(aInfo.mFullRange); // full/restricted range
// See VPXDecoder::VPXStreamInfo enums
writer.WriteU8(aInfo.mColorPrimaries); // color primaries
writer.WriteU8(aInfo.mTransferFunction); // transfer characteristics
writer.WriteU8(2); // matrix coefficients: unspecified
writer.WriteBits(0,
16); // codecIntializationDataSize (must be 0 for VP8/VP9)
}
/* static */
bool VPXDecoder::SetVideoInfo(VideoInfo* aDestInfo, const nsAString& aCodec) {
VPXDecoder::VPXStreamInfo info;
uint8_t level = 0;
uint8_t chroma = 1;
VideoColorSpace colorSpace;
if (!ExtractVPXCodecDetails(aCodec, info.mProfile, level, info.mBitDepth,
chroma, colorSpace)) {
return false;
}
aDestInfo->mColorPrimaries =
gfxUtils::CicpToColorPrimaries(colorSpace.mPrimaries, sPDMLog);
aDestInfo->mTransferFunction =
gfxUtils::CicpToTransferFunction(colorSpace.mTransfer);
aDestInfo->mColorDepth = gfx::ColorDepthForBitDepth(info.mBitDepth);
VPXDecoder::SetChroma(info, chroma);
info.mFullRange = colorSpace.mRange == ColorRange::FULL;
RefPtr<MediaByteBuffer> extraData = new MediaByteBuffer();
VPXDecoder::GetVPCCBox(extraData, info);
aDestInfo->mExtraData = extraData;
return true;
}
/* static */
void VPXDecoder::SetChroma(VPXStreamInfo& aDestInfo, uint8_t chroma) {
switch (chroma) {
case 0:
case 1:
aDestInfo.mSubSampling_x = true;
aDestInfo.mSubSampling_y = true;
break;
case 2:
aDestInfo.mSubSampling_x = true;
aDestInfo.mSubSampling_y = false;
break;
case 3:
aDestInfo.mSubSampling_x = false;
aDestInfo.mSubSampling_y = false;
break;
}
}
/* static */
void VPXDecoder::ReadVPCCBox(VPXStreamInfo& aDestInfo, MediaByteBuffer* aBox) {
BitReader reader(aBox);
reader.ReadBits(8); // version
reader.ReadBits(24); // flags
aDestInfo.mProfile = reader.ReadBits(8);
reader.ReadBits(8); // level
aDestInfo.mBitDepth = reader.ReadBits(4);
SetChroma(aDestInfo, reader.ReadBits(3));
aDestInfo.mFullRange = reader.ReadBit();
aDestInfo.mColorPrimaries = reader.ReadBits(8); // color primaries
aDestInfo.mTransferFunction = reader.ReadBits(8); // transfer characteristics
reader.ReadBits(8); // matrix coefficients
MOZ_ASSERT(reader.ReadBits(16) ==
0); // codecInitializationDataSize (must be 0 for VP8/VP9)
}
} // namespace mozilla
#undef LOG