chromium/media/parsers/temporal_scalability_id_extractor.cc

// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "media/parsers/temporal_scalability_id_extractor.h"

#include <bitset>

#include "base/notimplemented.h"

namespace media {

TemporalScalabilityIdExtractor::TemporalScalabilityIdExtractor(VideoCodec codec,
                                                               int layer_count)
    : … { … }

bool TemporalScalabilityIdExtractor::ParseChunk(base::span<const uint8_t> chunk,
                                                uint32_t frame_id,
                                                BitstreamMetadata& md) { … }

bool TemporalScalabilityIdExtractor::ParseH264(base::span<const uint8_t> chunk,
                                               BitstreamMetadata& md) { … }

#if BUILDFLAG(ENABLE_PLATFORM_HEVC)
bool TemporalScalabilityIdExtractor::ParseHEVC(base::span<const uint8_t> chunk,
                                               BitstreamMetadata& md) {
  h265_->SetStream(chunk.data(), chunk.size());
  H265NALU nalu;
  H265NaluParser::Result result;
  while ((result = h265_->AdvanceToNextNALU(&nalu)) !=
         H265NaluParser::kEOStream) {
    if (result == H265NaluParser::Result::kInvalidStream) {
      return false;
    }
    // See section 7.3.1.1, NAL unit syntax in H265 spec.
    // https://www.itu.int/rec/T-REC-H.265
    // Unlike AVC, HEVC stores the temporal ID information in VCL NAL unit
    // header instead of using prefix NAL unit. According to HEVC spec,
    // TemporalId = nuh_temporal_id_plus1 − 1.
    if (nalu.nal_unit_type <= H265NALU::RSV_VCL31) {
      md.temporal_id = nalu.nuh_temporal_id_plus1 - 1;
      return true;
    }
  }
  return true;
}
#endif

bool TemporalScalabilityIdExtractor::ParseVP9(base::span<const uint8_t> chunk,
                                              uint32_t frame_id,
                                              int tid_by_svc_spec,
                                              BitstreamMetadata& md) { … }

int TemporalScalabilityIdExtractor::AssignTemporalIdBySvcSpec(
    uint32_t frame_id) { … }

TemporalScalabilityIdExtractor::~TemporalScalabilityIdExtractor() = default;
TemporalScalabilityIdExtractor::BitstreamMetadata::BitstreamMetadata() =
    default;
TemporalScalabilityIdExtractor::BitstreamMetadata::~BitstreamMetadata() =
    default;

}  // namespace media