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webrtc/modules/video_coding/utility/vp9_uncompressed_header_parser.cc
Erik Språng cc69ea4a93 Fix parsing of vp9 skip level segmentation feature 
Bug: chromium:1241297
Change-Id: I44c3e8eddcb2467aae7433f3907cff34fa807f69
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/229302
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34803}
2021-08-19 12:16:00 +00:00

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/*
* Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/video_coding/utility/vp9_uncompressed_header_parser.h"
#include "absl/strings/string_view.h"
#include "rtc_base/bit_buffer.h"
#include "rtc_base/logging.h"
#include "rtc_base/strings/string_builder.h"
namespace webrtc {
// Evaluates x and returns false if false.
#define RETURN_IF_FALSE(x) \
if (!(x)) { \
return false; \
}
// Evaluates x, which is intended to return an optional. If result is nullopt,
// returns false. Else, calls fun() with the dereferenced optional as parameter.
#define READ_OR_RETURN(x, fun) \
do { \
if (auto optional_val = (x)) { \
fun(*optional_val); \
} else { \
return false; \
} \
} while (false)
namespace {
const size_t kVp9NumRefsPerFrame = 3;
const size_t kVp9MaxRefLFDeltas = 4;
const size_t kVp9MaxModeLFDeltas = 2;
const size_t kVp9MinTileWidthB64 = 4;
const size_t kVp9MaxTileWidthB64 = 64;
class BitstreamReader {
public:
explicit BitstreamReader(rtc::BitBuffer* buffer) : buffer_(buffer) {}
// Reads on bit from the input stream and:
// * returns false if bit cannot be read
// * calls f_true() if bit is true, returns return value of that function
// * calls f_else() if bit is false, returns return value of that function
bool IfNextBoolean(
std::function<bool()> f_true,
std::function<bool()> f_false = [] { return true; }) {
uint32_t val;
if (!buffer_->ReadBits(1, val)) {
return false;
}
if (val != 0) {
return f_true();
}
return f_false();
}
absl::optional<bool> ReadBoolean() {
uint32_t val;
if (!buffer_->ReadBits(1, val)) {
return {};
}
return {val != 0};
}
// Reads a bit from the input stream and returns:
// * false if bit cannot be read
// * true if bit matches expected_val
// * false if bit does not match expected_val - in which case `error_msg` is
// logged as warning, if provided.
bool VerifyNextBooleanIs(bool expected_val, absl::string_view error_msg) {
uint32_t val;
if (!buffer_->ReadBits(1, val)) {
return false;
}
if ((val != 0) != expected_val) {
if (!error_msg.empty()) {
RTC_LOG(LS_WARNING) << error_msg;
}
return false;
}
return true;
}
// Reads `bits` bits from the bitstream and interprets them as an unsigned
// integer that gets cast to the type T before returning.
// Returns nullopt if all bits cannot be read.
// If number of bits matches size of data type, the bits parameter may be
// omitted. Ex:
// ReadUnsigned<uint8_t>(2); // Returns uint8_t with 2 LSB populated.
// ReadUnsigned<uint8_t>(); // Returns uint8_t with all 8 bits populated.
template <typename T>
absl::optional<T> ReadUnsigned(int bits = sizeof(T) * 8) {
RTC_DCHECK_LE(bits, 32);
RTC_DCHECK_LE(bits, sizeof(T) * 8);
uint32_t val;
if (!buffer_->ReadBits(bits, val)) {
return {};
}
return (static_cast<T>(val));
}
// Helper method that reads `num_bits` from the bitstream, returns:
// * false if bits cannot be read.
// * true if `expected_val` matches the read bits
// * false if `expected_val` does not match the read bits, and logs
// `error_msg` as a warning (if provided).
bool VerifyNextUnsignedIs(int num_bits,
uint32_t expected_val,
absl::string_view error_msg) {
uint32_t val;
if (!buffer_->ReadBits(num_bits, val)) {
return false;
}
if (val != expected_val) {
if (!error_msg.empty()) {
RTC_LOG(LS_WARNING) << error_msg;
}
return false;
}
return true;
}
// Basically the same as ReadUnsigned() - but for signed integers.
// Here `bits` indicates the size of the value - number of bits read from the
// bit buffer is one higher (the sign bit). This is made to matche the spec in
// which eg s(4) = f(1) sign-bit, plus an f(4).
template <typename T>
absl::optional<T> ReadSigned(int bits = sizeof(T) * 8) {
uint32_t sign;
if (!buffer_->ReadBits(1, sign)) {
return {};
}
uint32_t val;
if (!buffer_->ReadBits(bits, val)) {
return {};
}
int64_t sign_val = val;
if (sign != 0) {
sign_val = -sign_val;
}
return {static_cast<T>(sign_val)};
}
// Reads `bits` from the bitstream, disregarding their value.
// Returns true if full number of bits were read, false otherwise.
bool ConsumeBits(int bits) { return buffer_->ConsumeBits(bits); }
void GetPosition(size_t* out_byte_offset, size_t* out_bit_offset) const {
buffer_->GetCurrentOffset(out_byte_offset, out_bit_offset);
}
private:
rtc::BitBuffer* buffer_;
};
bool Vp9ReadColorConfig(BitstreamReader* br,
Vp9UncompressedHeader* frame_info) {
if (frame_info->profile == 2 || frame_info->profile == 3) {
READ_OR_RETURN(br->ReadBoolean(), [frame_info](bool ten_or_twelve_bits) {
frame_info->bit_detph =
ten_or_twelve_bits ? Vp9BitDept::k12Bit : Vp9BitDept::k10Bit;
});
} else {
frame_info->bit_detph = Vp9BitDept::k8Bit;
}
READ_OR_RETURN(
br->ReadUnsigned<uint8_t>(3), [frame_info](uint8_t color_space) {
frame_info->color_space = static_cast<Vp9ColorSpace>(color_space);
});
if (frame_info->color_space != Vp9ColorSpace::CS_RGB) {
READ_OR_RETURN(br->ReadBoolean(), [frame_info](bool color_range) {
frame_info->color_range =
color_range ? Vp9ColorRange::kFull : Vp9ColorRange::kStudio;
});
if (frame_info->profile == 1 || frame_info->profile == 3) {
READ_OR_RETURN(br->ReadUnsigned<uint8_t>(2),
[frame_info](uint8_t subsampling) {
switch (subsampling) {
case 0b00:
frame_info->sub_sampling = Vp9YuvSubsampling::k444;
break;
case 0b01:
frame_info->sub_sampling = Vp9YuvSubsampling::k440;
break;
case 0b10:
frame_info->sub_sampling = Vp9YuvSubsampling::k422;
break;
case 0b11:
frame_info->sub_sampling = Vp9YuvSubsampling::k420;
break;
}
});
RETURN_IF_FALSE(br->VerifyNextBooleanIs(
0, "Failed to parse header. Reserved bit set."));
} else {
// Profile 0 or 2.
frame_info->sub_sampling = Vp9YuvSubsampling::k420;
}
} else {
// SRGB
frame_info->color_range = Vp9ColorRange::kFull;
if (frame_info->profile == 1 || frame_info->profile == 3) {
frame_info->sub_sampling = Vp9YuvSubsampling::k444;
RETURN_IF_FALSE(br->VerifyNextBooleanIs(
0, "Failed to parse header. Reserved bit set."));
} else {
RTC_LOG(LS_WARNING) << "Failed to parse header. 4:4:4 color not supported"
" in profile 0 or 2.";
return false;
}
}
return true;
}
bool ReadRefreshFrameFlags(BitstreamReader* br,
Vp9UncompressedHeader* frame_info) {
// Refresh frame flags.
READ_OR_RETURN(br->ReadUnsigned<uint8_t>(), [frame_info](uint8_t flags) {
for (int i = 0; i < 8; ++i) {
frame_info->updated_buffers.set(i, (flags & (0x01 << (7 - i))) != 0);
}
});
return true;
}
bool Vp9ReadFrameSize(BitstreamReader* br, Vp9UncompressedHeader* frame_info) {
// 16 bits: frame (width|height) - 1.
READ_OR_RETURN(br->ReadUnsigned<uint16_t>(), [frame_info](uint16_t width) {
frame_info->frame_width = width + 1;
});
READ_OR_RETURN(br->ReadUnsigned<uint16_t>(), [frame_info](uint16_t height) {
frame_info->frame_height = height + 1;
});
return true;
}
bool Vp9ReadRenderSize(BitstreamReader* br, Vp9UncompressedHeader* frame_info) {
// render_and_frame_size_different
return br->IfNextBoolean(
[&] {
auto& pos = frame_info->render_size_position.emplace();
br->GetPosition(&pos.byte_offset, &pos.bit_offset);
// 16 bits: render (width|height) - 1.
READ_OR_RETURN(br->ReadUnsigned<uint16_t>(),
[frame_info](uint16_t width) {
frame_info->render_width = width + 1;
});
READ_OR_RETURN(br->ReadUnsigned<uint16_t>(),
[frame_info](uint16_t height) {
frame_info->render_height = height + 1;
});
return true;
},
/*else*/
[&] {
frame_info->render_height = frame_info->frame_height;
frame_info->render_width = frame_info->frame_width;
return true;
});
}
bool Vp9ReadFrameSizeFromRefs(BitstreamReader* br,
Vp9UncompressedHeader* frame_info) {
bool found_ref = false;
for (size_t i = 0; !found_ref && i < kVp9NumRefsPerFrame; i++) {
// Size in refs.
br->IfNextBoolean([&] {
frame_info->infer_size_from_reference = frame_info->reference_buffers[i];
found_ref = true;
return true;
});
}
if (!found_ref) {
if (!Vp9ReadFrameSize(br, frame_info)) {
return false;
}
}
return Vp9ReadRenderSize(br, frame_info);
}
bool Vp9ReadLoopfilter(BitstreamReader* br) {
// 6 bits: filter level.
// 3 bits: sharpness level.
RETURN_IF_FALSE(br->ConsumeBits(9));
return br->IfNextBoolean([&] { // if mode_ref_delta_enabled
return br->IfNextBoolean([&] { // if mode_ref_delta_update
for (size_t i = 0; i < kVp9MaxRefLFDeltas; i++) {
RETURN_IF_FALSE(br->IfNextBoolean([&] { return br->ConsumeBits(7); }));
}
for (size_t i = 0; i < kVp9MaxModeLFDeltas; i++) {
RETURN_IF_FALSE(br->IfNextBoolean([&] { return br->ConsumeBits(7); }));
}
return true;
});
});
}
bool Vp9ReadQp(BitstreamReader* br, Vp9UncompressedHeader* frame_info) {
READ_OR_RETURN(br->ReadUnsigned<uint8_t>(),
[frame_info](uint8_t qp) { frame_info->base_qp = qp; });
// yuv offsets
frame_info->is_lossless = frame_info->base_qp == 0;
for (int i = 0; i < 3; ++i) {
RETURN_IF_FALSE(br->IfNextBoolean([&] { // if delta_coded
READ_OR_RETURN(br->ReadUnsigned<int>(4), [&](int delta) {
if (delta != 0) {
frame_info->is_lossless = false;
}
});
return true;
}));
}
return true;
}
bool Vp9ReadSegmentationParams(BitstreamReader* br,
Vp9UncompressedHeader* frame_info) {
constexpr int kSegmentationFeatureBits[kVp9SegLvlMax] = {8, 6, 2, 0};
constexpr bool kSegmentationFeatureSigned[kVp9SegLvlMax] = {1, 1, 0, 0};
return br->IfNextBoolean([&] { // segmentation_enabled
frame_info->segmentation_enabled = true;
RETURN_IF_FALSE(br->IfNextBoolean([&] { // update_map
frame_info->segmentation_tree_probs.emplace();
for (int i = 0; i < 7; ++i) {
RETURN_IF_FALSE(br->IfNextBoolean(
[&] {
READ_OR_RETURN(br->ReadUnsigned<uint8_t>(), [&](uint8_t prob) {
(*frame_info->segmentation_tree_probs)[i] = prob;
});
return true;
},
[&] {
(*frame_info->segmentation_tree_probs)[i] = 255;
return true;
}));
}
// temporal_update
frame_info->segmentation_pred_prob.emplace();
return br->IfNextBoolean(
[&] {
for (int i = 0; i < 3; ++i) {
RETURN_IF_FALSE(br->IfNextBoolean(
[&] {
READ_OR_RETURN(
br->ReadUnsigned<uint8_t>(), [&](uint8_t prob) {
(*frame_info->segmentation_pred_prob)[i] = prob;
});
return true;
},
[&] {
(*frame_info->segmentation_pred_prob)[i] = 255;
return true;
}));
}
return true;
},
[&] {
frame_info->segmentation_pred_prob->fill(255);
return true;
});
}));
return br->IfNextBoolean([&] { // segmentation_update_data
RETURN_IF_FALSE(br->IfNextBoolean([&] {
frame_info->segmentation_is_delta = true;
return true;
}));
for (size_t i = 0; i < kVp9MaxSegments; ++i) {
for (size_t j = 0; j < kVp9SegLvlMax; ++j) {
RETURN_IF_FALSE(br->IfNextBoolean([&] { // feature_enabled
if (kSegmentationFeatureBits[j] == 0) {
// No feature bits used and no sign, just mark it and return.
frame_info->segmentation_features[i][j] = 1;
return true;
}
READ_OR_RETURN(
br->ReadUnsigned<uint8_t>(kSegmentationFeatureBits[j]),
[&](uint8_t feature_value) {
frame_info->segmentation_features[i][j] = feature_value;
});
if (kSegmentationFeatureSigned[j]) {
RETURN_IF_FALSE(br->IfNextBoolean([&] {
(*frame_info->segmentation_features[i][j]) *= -1;
return true;
}));
}
return true;
}));
}
}
return true;
});
});
}
bool Vp9ReadTileInfo(BitstreamReader* br, Vp9UncompressedHeader* frame_info) {
size_t mi_cols = (frame_info->frame_width + 7) >> 3;
size_t sb64_cols = (mi_cols + 7) >> 3;
size_t min_log2 = 0;
while ((kVp9MaxTileWidthB64 << min_log2) < sb64_cols) {
++min_log2;
}
size_t max_log2 = 1;
while ((sb64_cols >> max_log2) >= kVp9MinTileWidthB64) {
++max_log2;
}
--max_log2;
frame_info->tile_cols_log2 = min_log2;
bool done = false;
while (!done && frame_info->tile_cols_log2 < max_log2) {
RETURN_IF_FALSE(br->IfNextBoolean(
[&] {
++frame_info->tile_cols_log2;
return true;
},
[&] {
done = true;
return true;
}));
}
frame_info->tile_rows_log2 = 0;
RETURN_IF_FALSE(br->IfNextBoolean([&] {
++frame_info->tile_rows_log2;
return br->IfNextBoolean([&] {
++frame_info->tile_rows_log2;
return true;
});
}));
return true;
}
const Vp9InterpolationFilter kLiteralToType[4] = {
Vp9InterpolationFilter::kEightTapSmooth, Vp9InterpolationFilter::kEightTap,
Vp9InterpolationFilter::kEightTapSharp, Vp9InterpolationFilter::kBilinear};
} // namespace
std::string Vp9UncompressedHeader::ToString() const {
char buf[1024];
rtc::SimpleStringBuilder oss(buf);
oss << "Vp9UncompressedHeader { "
<< "profile = " << profile;
if (show_existing_frame) {
oss << ", show_existing_frame = " << *show_existing_frame << " }";
return oss.str();
}
oss << ", frame type = " << (is_keyframe ? "key" : "delta")
<< ", show_frame = " << (show_frame ? "true" : "false")
<< ", error_resilient = " << (error_resilient ? "true" : "false");
oss << ", bit_depth = ";
switch (bit_detph) {
case Vp9BitDept::k8Bit:
oss << "8bit";
break;
case Vp9BitDept::k10Bit:
oss << "10bit";
break;
case Vp9BitDept::k12Bit:
oss << "12bit";
break;
}
if (color_space) {
oss << ", color_space = ";
switch (*color_space) {
case Vp9ColorSpace::CS_UNKNOWN:
oss << "unknown";
break;
case Vp9ColorSpace::CS_BT_601:
oss << "CS_BT_601 Rec. ITU-R BT.601-7";
break;
case Vp9ColorSpace::CS_BT_709:
oss << "Rec. ITU-R BT.709-6";
break;
case Vp9ColorSpace::CS_SMPTE_170:
oss << "SMPTE-170";
break;
case Vp9ColorSpace::CS_SMPTE_240:
oss << "SMPTE-240";
break;
case Vp9ColorSpace::CS_BT_2020:
oss << "Rec. ITU-R BT.2020-2";
break;
case Vp9ColorSpace::CS_RESERVED:
oss << "Reserved";
break;
case Vp9ColorSpace::CS_RGB:
oss << "sRGB (IEC 61966-2-1)";
break;
}
}
if (color_range) {
oss << ", color_range = ";
switch (*color_range) {
case Vp9ColorRange::kFull:
oss << "full";
break;
case Vp9ColorRange::kStudio:
oss << "studio";
break;
}
}
if (sub_sampling) {
oss << ", sub_sampling = ";
switch (*sub_sampling) {
case Vp9YuvSubsampling::k444:
oss << "444";
break;
case Vp9YuvSubsampling::k440:
oss << "440";
break;
case Vp9YuvSubsampling::k422:
oss << "422";
break;
case Vp9YuvSubsampling::k420:
oss << "420";
break;
}
}
if (infer_size_from_reference) {
oss << ", infer_frame_resolution_from = " << *infer_size_from_reference;
} else {
oss << ", frame_width = " << frame_width
<< ", frame_height = " << frame_height;
}
if (render_width != 0 && render_height != 0) {
oss << ", render_width = " << render_width
<< ", render_height = " << render_height;
}
oss << ", base qp = " << base_qp;
if (reference_buffers[0] != -1) {
oss << ", last_buffer = " << reference_buffers[0];
}
if (reference_buffers[1] != -1) {
oss << ", golden_buffer = " << reference_buffers[1];
}
if (reference_buffers[2] != -1) {
oss << ", altref_buffer = " << reference_buffers[2];
}
oss << ", updated buffers = { ";
bool first = true;
for (int i = 0; i < 8; ++i) {
if (updated_buffers.test(i)) {
if (first) {
first = false;
} else {
oss << ", ";
}
oss << i;
}
}
oss << " }";
oss << ", compressed_header_size_bytes = " << compressed_header_size;
oss << " }";
return oss.str();
}
bool Parse(rtc::ArrayView<const uint8_t> buf,
Vp9UncompressedHeader* frame_info,
bool qp_only) {
rtc::BitBuffer bit_buffer(buf.data(), buf.size());
BitstreamReader br(&bit_buffer);
// Frame marker.
RETURN_IF_FALSE(br.VerifyNextUnsignedIs(
2, 0x2, "Failed to parse header. Frame marker should be 2."));
// Profile has low bit first.
READ_OR_RETURN(br.ReadBoolean(),
[frame_info](bool low) { frame_info->profile = int{low}; });
READ_OR_RETURN(br.ReadBoolean(), [frame_info](bool high) {
frame_info->profile |= int{high} << 1;
});
if (frame_info->profile > 2) {
RETURN_IF_FALSE(br.VerifyNextBooleanIs(
false, "Failed to get QP. Unsupported bitstream profile."));
}
// Show existing frame.
RETURN_IF_FALSE(br.IfNextBoolean([&] {
READ_OR_RETURN(br.ReadUnsigned<uint8_t>(3),
[frame_info](uint8_t frame_idx) {
frame_info->show_existing_frame = frame_idx;
});
return true;
}));
if (frame_info->show_existing_frame.has_value()) {
return true;
}
READ_OR_RETURN(br.ReadBoolean(), [frame_info](bool frame_type) {
// Frame type: KEY_FRAME(0), INTER_FRAME(1).
frame_info->is_keyframe = frame_type == 0;
});
READ_OR_RETURN(br.ReadBoolean(), [frame_info](bool show_frame) {
frame_info->show_frame = show_frame;
});
READ_OR_RETURN(br.ReadBoolean(), [frame_info](bool error_resilient) {
frame_info->error_resilient = error_resilient;
});
if (frame_info->is_keyframe) {
RETURN_IF_FALSE(br.VerifyNextUnsignedIs(
24, 0x498342, "Failed to get QP. Invalid sync code."));
if (!Vp9ReadColorConfig(&br, frame_info))
return false;
if (!Vp9ReadFrameSize(&br, frame_info))
return false;
if (!Vp9ReadRenderSize(&br, frame_info))
return false;
// Key-frames implicitly update all buffers.
frame_info->updated_buffers.set();
} else {
// Non-keyframe.
bool is_intra_only = false;
if (!frame_info->show_frame) {
READ_OR_RETURN(br.ReadBoolean(),
[&](bool intra_only) { is_intra_only = intra_only; });
}
if (!frame_info->error_resilient) {
RETURN_IF_FALSE(br.ConsumeBits(2)); // Reset frame context.
}
if (is_intra_only) {
RETURN_IF_FALSE(br.VerifyNextUnsignedIs(
24, 0x498342, "Failed to get QP. Invalid sync code."));
if (frame_info->profile > 0) {
if (!Vp9ReadColorConfig(&br, frame_info))
return false;
} else {
frame_info->color_space = Vp9ColorSpace::CS_BT_601;
frame_info->sub_sampling = Vp9YuvSubsampling::k420;
frame_info->bit_detph = Vp9BitDept::k8Bit;
}
frame_info->reference_buffers.fill(-1);
RETURN_IF_FALSE(ReadRefreshFrameFlags(&br, frame_info));
RETURN_IF_FALSE(Vp9ReadFrameSize(&br, frame_info));
RETURN_IF_FALSE(Vp9ReadRenderSize(&br, frame_info));
} else {
RETURN_IF_FALSE(ReadRefreshFrameFlags(&br, frame_info));
frame_info->reference_buffers_sign_bias[0] = false;
for (size_t i = 0; i < kVp9NumRefsPerFrame; i++) {
READ_OR_RETURN(br.ReadUnsigned<uint8_t>(3), [&](uint8_t idx) {
frame_info->reference_buffers[i] = idx;
});
READ_OR_RETURN(br.ReadBoolean(), [&](bool sign_bias) {
frame_info
->reference_buffers_sign_bias[Vp9ReferenceFrame::kLast + i] =
sign_bias;
});
}
if (!Vp9ReadFrameSizeFromRefs(&br, frame_info))
return false;
READ_OR_RETURN(br.ReadBoolean(), [&](bool allow_high_precision_mv) {
frame_info->allow_high_precision_mv = allow_high_precision_mv;
});
// Interpolation filter.
RETURN_IF_FALSE(br.IfNextBoolean(
[frame_info] {
frame_info->interpolation_filter =
Vp9InterpolationFilter::kSwitchable;
return true;
},
[&] {
READ_OR_RETURN(
br.ReadUnsigned<uint8_t>(2), [frame_info](uint8_t filter) {
frame_info->interpolation_filter = kLiteralToType[filter];
});
return true;
}));
}
}
if (!frame_info->error_resilient) {
// 1 bit: Refresh frame context.
// 1 bit: Frame parallel decoding mode.
RETURN_IF_FALSE(br.ConsumeBits(2));
}
// Frame context index.
READ_OR_RETURN(br.ReadUnsigned<uint8_t>(2),
[&](uint8_t idx) { frame_info->frame_context_idx = idx; });
if (!Vp9ReadLoopfilter(&br))
return false;
// Read base QP.
RETURN_IF_FALSE(Vp9ReadQp(&br, frame_info));
if (qp_only) {
// Not interested in the rest of the header, return early.
return true;
}
RETURN_IF_FALSE(Vp9ReadSegmentationParams(&br, frame_info));
RETURN_IF_FALSE(Vp9ReadTileInfo(&br, frame_info));
READ_OR_RETURN(br.ReadUnsigned<uint16_t>(), [frame_info](uint16_t size) {
frame_info->compressed_header_size = size;
});
// Trailing bits.
RETURN_IF_FALSE(br.ConsumeBits(bit_buffer.RemainingBitCount() % 8));
frame_info->uncompressed_header_size =
buf.size() - (bit_buffer.RemainingBitCount() / 8);
return true;
}
absl::optional<Vp9UncompressedHeader> ParseUncompressedVp9Header(
rtc::ArrayView<const uint8_t> buf) {
Vp9UncompressedHeader frame_info;
if (Parse(buf, &frame_info, /*qp_only=*/false) &&
frame_info.frame_width > 0) {
return frame_info;
}
return absl::nullopt;
}
namespace vp9 {
bool GetQp(const uint8_t* buf, size_t length, int* qp) {
Vp9UncompressedHeader frame_info;
if (!Parse(rtc::MakeArrayView(buf, length), &frame_info, /*qp_only=*/true)) {
return false;
}
*qp = frame_info.base_qp;
return true;
}
} // namespace vp9
} // namespace webrtc
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