mirror of
https://github.com/mollyim/webrtc.git
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ba91dbcb3e
by updating flag that T1 frame can be referenced when it is encoded rather than when it is sent for encoding. Otherwise when encoder drops T1 frame, configuration for following T2 frame would still try to reference that absent T1 frame leading to invalid references. Bug: None Change-Id: I6398275971596b0618bcf9c926f0282f74120976 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/202030 Reviewed-by: Philip Eliasson <philipel@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33002}
288 lines
10 KiB
C++
288 lines
10 KiB
C++
/*
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* Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/video_coding/svc/scalability_structure_full_svc.h"
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#include <utility>
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#include <vector>
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#include "absl/strings/string_view.h"
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#include "absl/types/optional.h"
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#include "api/transport/rtp/dependency_descriptor.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/logging.h"
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namespace webrtc {
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namespace {
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enum : int { kKey, kDelta };
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} // namespace
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constexpr int ScalabilityStructureFullSvc::kMaxNumSpatialLayers;
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constexpr int ScalabilityStructureFullSvc::kMaxNumTemporalLayers;
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constexpr absl::string_view ScalabilityStructureFullSvc::kFramePatternNames[];
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ScalabilityStructureFullSvc::ScalabilityStructureFullSvc(
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int num_spatial_layers,
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int num_temporal_layers)
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: num_spatial_layers_(num_spatial_layers),
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num_temporal_layers_(num_temporal_layers),
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active_decode_targets_(
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(uint32_t{1} << (num_spatial_layers * num_temporal_layers)) - 1) {
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RTC_DCHECK_LE(num_spatial_layers, kMaxNumSpatialLayers);
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RTC_DCHECK_LE(num_temporal_layers, kMaxNumTemporalLayers);
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}
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ScalabilityStructureFullSvc::~ScalabilityStructureFullSvc() = default;
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ScalabilityStructureFullSvc::StreamLayersConfig
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ScalabilityStructureFullSvc::StreamConfig() const {
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StreamLayersConfig result;
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result.num_spatial_layers = num_spatial_layers_;
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result.num_temporal_layers = num_temporal_layers_;
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result.scaling_factor_num[num_spatial_layers_ - 1] = 1;
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result.scaling_factor_den[num_spatial_layers_ - 1] = 1;
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for (int sid = num_spatial_layers_ - 1; sid > 0; --sid) {
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result.scaling_factor_num[sid - 1] = 1;
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result.scaling_factor_den[sid - 1] = 2 * result.scaling_factor_den[sid];
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}
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return result;
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}
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bool ScalabilityStructureFullSvc::TemporalLayerIsActive(int tid) const {
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if (tid >= num_temporal_layers_) {
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return false;
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}
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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if (DecodeTargetIsActive(sid, tid)) {
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return true;
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}
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}
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return false;
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}
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DecodeTargetIndication ScalabilityStructureFullSvc::Dti(
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int sid,
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int tid,
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const LayerFrameConfig& config) {
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if (sid < config.SpatialId() || tid < config.TemporalId()) {
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return DecodeTargetIndication::kNotPresent;
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}
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if (sid == config.SpatialId()) {
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if (tid == 0) {
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RTC_DCHECK_EQ(config.TemporalId(), 0);
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return DecodeTargetIndication::kSwitch;
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}
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if (tid == config.TemporalId()) {
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return DecodeTargetIndication::kDiscardable;
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}
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if (tid > config.TemporalId()) {
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RTC_DCHECK_GT(tid, config.TemporalId());
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return DecodeTargetIndication::kSwitch;
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}
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}
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RTC_DCHECK_GT(sid, config.SpatialId());
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RTC_DCHECK_GE(tid, config.TemporalId());
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if (config.IsKeyframe() || config.Id() == kKey) {
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return DecodeTargetIndication::kSwitch;
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}
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return DecodeTargetIndication::kRequired;
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}
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ScalabilityStructureFullSvc::FramePattern
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ScalabilityStructureFullSvc::NextPattern() const {
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switch (last_pattern_) {
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case kNone:
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case kDeltaT2B:
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return kDeltaT0;
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case kDeltaT2A:
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if (TemporalLayerIsActive(1)) {
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return kDeltaT1;
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}
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return kDeltaT0;
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case kDeltaT1:
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if (TemporalLayerIsActive(2)) {
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return kDeltaT2B;
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}
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return kDeltaT0;
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case kDeltaT0:
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if (TemporalLayerIsActive(2)) {
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return kDeltaT2A;
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}
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if (TemporalLayerIsActive(1)) {
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return kDeltaT1;
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}
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return kDeltaT0;
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}
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}
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std::vector<ScalableVideoController::LayerFrameConfig>
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ScalabilityStructureFullSvc::NextFrameConfig(bool restart) {
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std::vector<LayerFrameConfig> configs;
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if (active_decode_targets_.none()) {
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last_pattern_ = kNone;
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return configs;
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}
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configs.reserve(num_spatial_layers_);
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if (last_pattern_ == kNone || restart) {
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can_reference_t0_frame_for_spatial_id_.reset();
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last_pattern_ = kNone;
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}
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FramePattern current_pattern = NextPattern();
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absl::optional<int> spatial_dependency_buffer_id;
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switch (current_pattern) {
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case kDeltaT0:
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// Disallow temporal references cross T0 on higher temporal layers.
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can_reference_t1_frame_for_spatial_id_.reset();
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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if (!DecodeTargetIsActive(sid, /*tid=*/0)) {
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// Next frame from the spatial layer `sid` shouldn't depend on
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// potentially old previous frame from the spatial layer `sid`.
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can_reference_t0_frame_for_spatial_id_.reset(sid);
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continue;
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}
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configs.emplace_back();
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ScalableVideoController::LayerFrameConfig& config = configs.back();
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config.Id(last_pattern_ == kNone ? kKey : kDelta).S(sid).T(0);
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if (spatial_dependency_buffer_id) {
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config.Reference(*spatial_dependency_buffer_id);
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} else if (last_pattern_ == kNone) {
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config.Keyframe();
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}
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if (can_reference_t0_frame_for_spatial_id_[sid]) {
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config.ReferenceAndUpdate(BufferIndex(sid, /*tid=*/0));
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} else {
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// TODO(bugs.webrtc.org/11999): Propagate chain restart on delta frame
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// to ChainDiffCalculator
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config.Update(BufferIndex(sid, /*tid=*/0));
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}
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can_reference_t0_frame_for_spatial_id_.set(sid);
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spatial_dependency_buffer_id = BufferIndex(sid, /*tid=*/0);
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}
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break;
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case kDeltaT1:
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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if (!DecodeTargetIsActive(sid, /*tid=*/1) ||
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!can_reference_t0_frame_for_spatial_id_[sid]) {
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continue;
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}
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configs.emplace_back();
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ScalableVideoController::LayerFrameConfig& config = configs.back();
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config.Id(kDelta).S(sid).T(1);
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// Temporal reference.
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config.Reference(BufferIndex(sid, /*tid=*/0));
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// Spatial reference unless this is the lowest active spatial layer.
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if (spatial_dependency_buffer_id) {
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config.Reference(*spatial_dependency_buffer_id);
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}
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// No frame reference top layer frame, so no need save it into a buffer.
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if (num_temporal_layers_ > 2 || sid < num_spatial_layers_ - 1) {
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config.Update(BufferIndex(sid, /*tid=*/1));
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}
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spatial_dependency_buffer_id = BufferIndex(sid, /*tid=*/1);
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}
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break;
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case kDeltaT2A:
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case kDeltaT2B:
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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if (!DecodeTargetIsActive(sid, /*tid=*/2) ||
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!can_reference_t0_frame_for_spatial_id_[sid]) {
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continue;
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}
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configs.emplace_back();
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ScalableVideoController::LayerFrameConfig& config = configs.back();
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config.Id(kDelta).S(sid).T(2);
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// Temporal reference.
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if (current_pattern == kDeltaT2B &&
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can_reference_t1_frame_for_spatial_id_[sid]) {
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config.Reference(BufferIndex(sid, /*tid=*/1));
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} else {
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config.Reference(BufferIndex(sid, /*tid=*/0));
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}
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// Spatial reference unless this is the lowest active spatial layer.
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if (spatial_dependency_buffer_id) {
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config.Reference(*spatial_dependency_buffer_id);
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}
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// No frame reference top layer frame, so no need save it into a buffer.
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if (sid < num_spatial_layers_ - 1) {
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config.Update(BufferIndex(sid, /*tid=*/2));
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}
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spatial_dependency_buffer_id = BufferIndex(sid, /*tid=*/2);
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}
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break;
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case kNone:
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RTC_NOTREACHED();
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break;
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}
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if (configs.empty() && !restart) {
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RTC_LOG(LS_WARNING) << "Failed to generate configuration for L"
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<< num_spatial_layers_ << "T" << num_temporal_layers_
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<< " with active decode targets "
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<< active_decode_targets_.to_string('-').substr(
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active_decode_targets_.size() -
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num_spatial_layers_ * num_temporal_layers_)
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<< " and transition from "
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<< kFramePatternNames[last_pattern_] << " to "
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<< kFramePatternNames[current_pattern]
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<< ". Resetting.";
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return NextFrameConfig(/*restart=*/true);
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}
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last_pattern_ = current_pattern;
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return configs;
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}
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GenericFrameInfo ScalabilityStructureFullSvc::OnEncodeDone(
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const LayerFrameConfig& config) {
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if (config.TemporalId() == 1) {
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can_reference_t1_frame_for_spatial_id_.set(config.SpatialId());
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}
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GenericFrameInfo frame_info;
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frame_info.spatial_id = config.SpatialId();
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frame_info.temporal_id = config.TemporalId();
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frame_info.encoder_buffers = config.Buffers();
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frame_info.decode_target_indications.reserve(num_spatial_layers_ *
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num_temporal_layers_);
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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for (int tid = 0; tid < num_temporal_layers_; ++tid) {
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frame_info.decode_target_indications.push_back(Dti(sid, tid, config));
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}
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}
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if (config.TemporalId() == 0) {
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frame_info.part_of_chain.resize(num_spatial_layers_);
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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frame_info.part_of_chain[sid] = config.SpatialId() <= sid;
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}
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} else {
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frame_info.part_of_chain.assign(num_spatial_layers_, false);
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}
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frame_info.active_decode_targets = active_decode_targets_;
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return frame_info;
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}
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void ScalabilityStructureFullSvc::OnRatesUpdated(
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const VideoBitrateAllocation& bitrates) {
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for (int sid = 0; sid < num_spatial_layers_; ++sid) {
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// Enable/disable spatial layers independetely.
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bool active = true;
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for (int tid = 0; tid < num_temporal_layers_; ++tid) {
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// To enable temporal layer, require bitrates for lower temporal layers.
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active = active && bitrates.GetBitrate(sid, tid) > 0;
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SetDecodeTargetIsActive(sid, tid, active);
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}
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}
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}
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} // namespace webrtc
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