// Copyright 2022 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 "vp9_video_rate_control_wrapper.h"
#include "third_party/libvpx/source/libvpx/vp9/ratectrl_rtc.h"
namespace {
// The return value is expressed as a percentage of the average. For example,
// to allocate no more than 4.5 frames worth of bitrate to a keyframe, the
// return value is 450.
uint32_t MaxSizeOfKeyframeAsPercentage(uint32_t optimal_buffer_size,
uint32_t max_framerate) {
// Set max to the optimal buffer level (normalized by target BR),
// and scaled by a scale_par.
// Max target size = scale_par * optimal_buffer_size * targetBR[Kbps].
// This value is presented in percentage of perFrameBw:
// perFrameBw = targetBR[Kbps] * 1000 / framerate.
// The target in % is as follows:
const double target_size_byte_per_frame = optimal_buffer_size * 0.5;
const uint32_t target_size_kbyte =
target_size_byte_per_frame * max_framerate / 1000;
const uint32_t target_size_kbyte_as_percent = target_size_kbyte * 100;
// Don't go below 3 times the per frame bandwidth.
constexpr uint32_t kMinIntraSizePercentage = 300u;
return kMinIntraSizePercentage > target_size_kbyte_as_percent
? kMinIntraSizePercentage
: target_size_kbyte_as_percent;
}
} // namespace
namespace media {
template <>
int VP9RateControl::GetLoopfilterLevel() const {
DCHECK(impl_);
return impl_->GetLoopfilterLevel();
}
template <>
void VP9RateControl::PostEncodeUpdate(uint64_t encoded_frame_size,
const FrameParams& frame_params) {
DCHECK(impl_);
return impl_->PostEncodeUpdate(encoded_frame_size,
ConvertFrameParams(frame_params));
}
template <>
libvpx::VP9RateControlRtcConfig VP9RateControl::ConvertControlConfig(
const RateControlConfig& config) {
libvpx::VP9RateControlRtcConfig rc_config;
rc_config.width = config.width;
rc_config.height = config.height;
rc_config.target_bandwidth = config.target_bandwidth;
rc_config.framerate = config.framerate;
rc_config.max_quantizer = config.max_quantizer;
rc_config.min_quantizer = config.min_quantizer;
// These default values come from
// //third_party/webrtc/modules/video_coding/codecs/vp9/libvpx_vp9_encoder.cc.
rc_config.buf_initial_sz = 500;
rc_config.buf_optimal_sz = 600;
rc_config.buf_sz = 1000;
rc_config.undershoot_pct = 50;
rc_config.overshoot_pct = 50;
rc_config.aq_mode = 0;
rc_config.rc_mode = VPX_CBR;
rc_config.max_intra_bitrate_pct = MaxSizeOfKeyframeAsPercentage(
rc_config.buf_optimal_sz, rc_config.framerate);
rc_config.max_inter_bitrate_pct = 0;
rc_config.ss_number_layers = config.ss_number_layers;
rc_config.ts_number_layers = config.ts_number_layers;
for (int tid = 0; tid < config.ts_number_layers; ++tid) {
rc_config.ts_rate_decimator[tid] = config.ts_rate_decimator[tid];
}
for (int sid = 0; sid < config.ss_number_layers; ++sid) {
rc_config.scaling_factor_num[sid] = config.scaling_factor_num[sid];
rc_config.scaling_factor_den[sid] = config.scaling_factor_den[sid];
for (int tid = 0; tid < config.ts_number_layers; ++tid) {
const int i = sid * config.ts_number_layers + tid;
rc_config.max_quantizers[i] = config.max_quantizers[i];
rc_config.min_quantizers[i] = config.min_quantizers[i];
rc_config.layer_target_bitrate[i] = config.layer_target_bitrate[i];
}
}
return rc_config;
}
template <>
libvpx::VP9FrameParamsQpRTC VP9RateControl::ConvertFrameParams(
const FrameParams& frame_params) {
libvpx::VP9FrameParamsQpRTC rc_params;
rc_params.spatial_layer_id = frame_params.spatial_layer_id;
rc_params.temporal_layer_id = frame_params.temporal_layer_id;
rc_params.frame_type =
frame_params.frame_type == FrameParams::FrameType::kKeyFrame
? libvpx::RcFrameType::kKeyFrame
: libvpx::RcFrameType::kInterFrame;
return rc_params;
}
} // namespace media
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