1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151
|
/*
* Copyright (c) 2020 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/codecs/av1/av1_svc_config.h"
#include <algorithm>
#include <cmath>
#include <memory>
#include <optional>
#include "absl/container/inlined_vector.h"
#include "api/video/video_codec_type.h"
#include "api/video_codecs/scalability_mode.h"
#include "api/video_codecs/spatial_layer.h"
#include "api/video_codecs/video_codec.h"
#include "modules/video_coding/svc/create_scalability_structure.h"
#include "modules/video_coding/svc/scalability_mode_util.h"
#include "modules/video_coding/svc/scalable_video_controller.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/strings/string_builder.h"
namespace webrtc {
namespace {
const int kMinAv1SpatialLayerLongSideLength = 240;
const int kMinAv1SpatialLayerShortSideLength = 135;
int GetLimitedNumSpatialLayers(int width, int height) {
const bool is_landscape = width >= height;
const int min_width = is_landscape ? kMinAv1SpatialLayerLongSideLength
: kMinAv1SpatialLayerShortSideLength;
const int min_height = is_landscape ? kMinAv1SpatialLayerShortSideLength
: kMinAv1SpatialLayerLongSideLength;
const int num_layers_fit_horz = static_cast<int>(
std::floor(1 + std::max(0.0f, std::log2(1.0f * width / min_width))));
const int num_layers_fit_vert = static_cast<int>(
std::floor(1 + std::max(0.0f, std::log2(1.0f * height / min_height))));
return std::min(num_layers_fit_horz, num_layers_fit_vert);
}
std::optional<ScalabilityMode> BuildScalabilityMode(int num_temporal_layers,
int num_spatial_layers) {
char name[20];
SimpleStringBuilder ss(name);
ss << "L" << num_spatial_layers << "T" << num_temporal_layers;
if (num_spatial_layers > 1) {
ss << "_KEY";
}
return ScalabilityModeFromString(name);
}
} // namespace
absl::InlinedVector<ScalabilityMode, kScalabilityModeCount>
LibaomAv1EncoderSupportedScalabilityModes() {
absl::InlinedVector<ScalabilityMode, kScalabilityModeCount> scalability_modes;
for (ScalabilityMode scalability_mode : kAllScalabilityModes) {
if (ScalabilityStructureConfig(scalability_mode) != std::nullopt) {
scalability_modes.push_back(scalability_mode);
}
}
return scalability_modes;
}
bool LibaomAv1EncoderSupportsScalabilityMode(ScalabilityMode scalability_mode) {
// For libaom AV1, the scalability mode is supported if we can create the
// scalability structure.
return ScalabilityStructureConfig(scalability_mode) != std::nullopt;
}
bool SetAv1SvcConfig(VideoCodec& video_codec,
int num_temporal_layers,
int num_spatial_layers) {
RTC_DCHECK_EQ(video_codec.codecType, kVideoCodecAV1);
std::optional<ScalabilityMode> scalability_mode =
video_codec.GetScalabilityMode();
if (!scalability_mode.has_value()) {
scalability_mode =
BuildScalabilityMode(num_temporal_layers, num_spatial_layers);
if (!scalability_mode) {
RTC_LOG(LS_WARNING) << "Scalability mode is not set, using 'L1T1'.";
scalability_mode = ScalabilityMode::kL1T1;
}
}
bool requested_single_spatial_layer =
ScalabilityModeToNumSpatialLayers(*scalability_mode) == 1;
if (ScalabilityMode reduced = LimitNumSpatialLayers(
*scalability_mode,
GetLimitedNumSpatialLayers(video_codec.width, video_codec.height));
*scalability_mode != reduced) {
RTC_LOG(LS_WARNING) << "Reduced number of spatial layers from "
<< ScalabilityModeToString(*scalability_mode) << " to "
<< ScalabilityModeToString(reduced);
scalability_mode = reduced;
}
std::unique_ptr<ScalableVideoController> structure =
CreateScalabilityStructure(*scalability_mode);
if (structure == nullptr) {
RTC_LOG(LS_WARNING) << "Failed to create structure "
<< static_cast<int>(*scalability_mode);
return false;
}
video_codec.SetScalabilityMode(*scalability_mode);
ScalableVideoController::StreamLayersConfig info = structure->StreamConfig();
for (int sl_idx = 0; sl_idx < info.num_spatial_layers; ++sl_idx) {
SpatialLayer& spatial_layer = video_codec.spatialLayers[sl_idx];
spatial_layer.width = video_codec.width * info.scaling_factor_num[sl_idx] /
info.scaling_factor_den[sl_idx];
spatial_layer.height = video_codec.height *
info.scaling_factor_num[sl_idx] /
info.scaling_factor_den[sl_idx];
spatial_layer.maxFramerate = video_codec.maxFramerate;
spatial_layer.numberOfTemporalLayers = info.num_temporal_layers;
spatial_layer.active = true;
}
if (requested_single_spatial_layer) {
SpatialLayer& spatial_layer = video_codec.spatialLayers[0];
spatial_layer.minBitrate = video_codec.minBitrate;
spatial_layer.maxBitrate = video_codec.maxBitrate;
spatial_layer.targetBitrate =
(video_codec.minBitrate + video_codec.maxBitrate) / 2;
return true;
}
for (int sl_idx = 0; sl_idx < info.num_spatial_layers; ++sl_idx) {
SpatialLayer& spatial_layer = video_codec.spatialLayers[sl_idx];
const int num_pixels = spatial_layer.width * spatial_layer.height;
int min_bitrate_kbps = (480.0 * std::sqrt(num_pixels) - 95'000.0) / 1000.0;
spatial_layer.minBitrate = std::max(min_bitrate_kbps, 20);
spatial_layer.maxBitrate = 50 + static_cast<int>(1.6 * num_pixels / 1000.0);
spatial_layer.targetBitrate =
(spatial_layer.minBitrate + spatial_layer.maxBitrate) / 2;
}
return true;
}
} // namespace webrtc
|