webrtc_m130/rtc_base/experiments/encoder_info_settings.cc
Åsa Persson 04d06457f5 Use encoding max bitrate if configured when applying bitrate limits.
Currently the min of the default bitrate and configured bitrate is used.

Add default bitrate limits for 1080p.

Bug: b/396641469
Change-Id: Iabf243627a6dcbaa1e2f14d4f201c9482f3958d5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/377123
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Åsa Persson <asapersson@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43923}
2025-02-19 03:09:10 -08:00

262 lines
10 KiB
C++

/*
* Copyright 2021 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 "rtc_base/experiments/encoder_info_settings.h"
#include <stdio.h>
#include "absl/strings/string_view.h"
#include "api/field_trials_view.h"
#include "rtc_base/experiments/field_trial_list.h"
#include "rtc_base/logging.h"
namespace webrtc {
namespace {
std::vector<VideoEncoder::ResolutionBitrateLimits> ToResolutionBitrateLimits(
const std::vector<EncoderInfoSettings::BitrateLimit>& limits) {
std::vector<VideoEncoder::ResolutionBitrateLimits> result;
for (const auto& limit : limits) {
result.push_back(VideoEncoder::ResolutionBitrateLimits(
limit.frame_size_pixels, limit.min_start_bitrate_bps,
limit.min_bitrate_bps, limit.max_bitrate_bps));
}
return result;
}
constexpr float kDefaultMinBitratebps = 30000;
} // namespace
// Default bitrate limits for simulcast with one active stream:
// {frame_size_pixels, min_start_bitrate_bps, min_bitrate_bps, max_bitrate_bps}.
std::vector<VideoEncoder::ResolutionBitrateLimits>
EncoderInfoSettings::GetDefaultSinglecastBitrateLimits(
VideoCodecType codec_type) {
if (codec_type == kVideoCodecAV1) {
// AV1 singlecast max bitrate limits are higher than AV1 SVC max limits.
// This is because in singlecast we normally have just one receiver, BWE is
// known end-to-end and the encode target bitrate guarantees delivery of
// video.
// The min bitrate limits are not used in singlecast (used in SVC/simulcast
// to de-/activate spatial layers) and are set to zero. Send resolution in
// singlecast is assumed to be regulated by QP-based quality scaler.
return {
{320 * 180, 0, 0, 256000}, {480 * 270, 176000, 0, 384000},
{640 * 360, 256000, 0, 512000}, {960 * 540, 384000, 0, 1024000},
{1280 * 720, 576000, 0, 1536000}, {1920 * 1080, 1000000, 0, 3700000}};
}
if (codec_type == kVideoCodecVP9 || codec_type == kVideoCodecH265) {
// VP9 singlecast bitrate limits are derived ~directly from VP9 SVC bitrate
// limits. The current max limits are unnecessarily too strict for
// singlecast, where BWE is known end-to-end, especially for low
// resolutions.
// TODO(crbugs.com/39206082): Consider fine-tuning H.265 to have its own
// bitrate settings separate from VP9.
return {{320 * 180, 0, 30000, 150000},
{480 * 270, 120000, 30000, 300000},
{640 * 360, 190000, 30000, 420000},
{960 * 540, 350000, 30000, 1000000},
{1280 * 720, 480000, 30000, 1500000},
{1920 * 1080, 1000000, 30000, 3700000}};
}
// VP8 and other codecs.
return {{320 * 180, 0, 30000, 300000},
{480 * 270, 200000, 30000, 500000},
{640 * 360, 300000, 30000, 800000},
{960 * 540, 500000, 30000, 1500000},
{1280 * 720, 900000, 30000, 2500000},
{1920 * 1080, 2000000, 30000, 5000000}};
}
std::optional<VideoEncoder::ResolutionBitrateLimits>
EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
VideoCodecType codec_type,
int frame_size_pixels) {
VideoEncoder::EncoderInfo info;
info.resolution_bitrate_limits =
GetDefaultSinglecastBitrateLimits(codec_type);
return info.GetEncoderBitrateLimitsForResolution(frame_size_pixels);
}
// Return the suitable bitrate limits for specified resolution when qp is
// untrusted, they are experimental values.
std::vector<VideoEncoder::ResolutionBitrateLimits>
EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsWhenQpIsUntrusted(
VideoCodecType codec_type) {
if (codec_type == kVideoCodecH265) {
// Similar settings from the simulcast bitate limits for H.265.
return {{0 * 0, 0, 0, 0},
{320 * 180, 0, 30000, 150000},
{480 * 270, 150000, 30000, 300000},
{640 * 360, 300000, 30000, 420000},
{960 * 540, 420000, 30000, 1000000},
{1280 * 720, 1000000, 30000, 1500000},
{1920 * 1080, 1500000, 30000, 3300000}};
} else {
// Settings for H.264. Other codecs will not work in QP-untrusted mode.
return {{0 * 0, 0, 0, 0},
{320 * 180, 0, 30000, 300000},
{480 * 270, 300000, 30000, 500000},
{640 * 360, 500000, 30000, 800000},
{960 * 540, 800000, 30000, 1500000},
{1280 * 720, 1500000, 30000, 2500000},
{1920 * 1080, 2500000, 30000, 4000000}};
}
}
// Through linear interpolation, return the bitrate limit corresponding to the
// specified |frame_size_pixels|.
std::optional<VideoEncoder::ResolutionBitrateLimits>
EncoderInfoSettings::GetSinglecastBitrateLimitForResolutionWhenQpIsUntrusted(
std::optional<int> frame_size_pixels,
const std::vector<VideoEncoder::ResolutionBitrateLimits>&
resolution_bitrate_limits) {
if (!frame_size_pixels.has_value() || frame_size_pixels.value() <= 0) {
return std::nullopt;
}
std::vector<VideoEncoder::ResolutionBitrateLimits> bitrate_limits =
resolution_bitrate_limits;
// Sort the list of bitrate limits by resolution.
sort(bitrate_limits.begin(), bitrate_limits.end(),
[](const VideoEncoder::ResolutionBitrateLimits& lhs,
const VideoEncoder::ResolutionBitrateLimits& rhs) {
return lhs.frame_size_pixels < rhs.frame_size_pixels;
});
if (bitrate_limits.empty()) {
return std::nullopt;
}
int interpolation_index = -1;
for (size_t i = 0; i < bitrate_limits.size(); ++i) {
if (bitrate_limits[i].frame_size_pixels >= frame_size_pixels.value()) {
interpolation_index = i;
break;
}
}
// -1 means that the maximum resolution is exceeded, we will select the
// largest data as the return result.
if (interpolation_index == -1) {
return *bitrate_limits.rbegin();
}
// If we have a matching resolution, return directly without interpolation.
if (bitrate_limits[interpolation_index].frame_size_pixels ==
frame_size_pixels.value()) {
return bitrate_limits[interpolation_index];
}
// 0 means our resolution is smaller than the smallest resolution in the list,
// we will select smallest data as the return result.
if (interpolation_index == 0) {
return *bitrate_limits.begin();
}
// No matching resolution, do a linear interpolate.
int lower_pixel_count =
bitrate_limits[interpolation_index - 1].frame_size_pixels;
int upper_pixel_count = bitrate_limits[interpolation_index].frame_size_pixels;
float alpha = (frame_size_pixels.value() - lower_pixel_count) * 1.0 /
(upper_pixel_count - lower_pixel_count);
int min_start_bitrate_bps = static_cast<int>(
bitrate_limits[interpolation_index].min_start_bitrate_bps * alpha +
bitrate_limits[interpolation_index - 1].min_start_bitrate_bps *
(1.0 - alpha));
int max_bitrate_bps = static_cast<int>(
bitrate_limits[interpolation_index].max_bitrate_bps * alpha +
bitrate_limits[interpolation_index - 1].max_bitrate_bps * (1.0 - alpha));
if (max_bitrate_bps >= min_start_bitrate_bps) {
return VideoEncoder::ResolutionBitrateLimits(
frame_size_pixels.value(), min_start_bitrate_bps, kDefaultMinBitratebps,
max_bitrate_bps);
} else {
RTC_LOG(LS_WARNING)
<< "BitRate interpolation calculating result is abnormal. "
<< " lower_pixel_count = " << lower_pixel_count
<< " upper_pixel_count = " << upper_pixel_count
<< " frame_size_pixels = " << frame_size_pixels.value()
<< " min_start_bitrate_bps = " << min_start_bitrate_bps
<< " min_bitrate_bps = " << kDefaultMinBitratebps
<< " max_bitrate_bps = " << max_bitrate_bps;
return std::nullopt;
}
}
EncoderInfoSettings::EncoderInfoSettings(const FieldTrialsView& field_trials,
absl::string_view name)
: requested_resolution_alignment_("requested_resolution_alignment"),
apply_alignment_to_all_simulcast_layers_(
"apply_alignment_to_all_simulcast_layers") {
FieldTrialStructList<BitrateLimit> bitrate_limits(
{FieldTrialStructMember(
"frame_size_pixels",
[](BitrateLimit* b) { return &b->frame_size_pixels; }),
FieldTrialStructMember(
"min_start_bitrate_bps",
[](BitrateLimit* b) { return &b->min_start_bitrate_bps; }),
FieldTrialStructMember(
"min_bitrate_bps",
[](BitrateLimit* b) { return &b->min_bitrate_bps; }),
FieldTrialStructMember(
"max_bitrate_bps",
[](BitrateLimit* b) { return &b->max_bitrate_bps; })},
{});
std::string experiment_string = field_trials.Lookup(name);
if (experiment_string.empty()) {
// Encoder name not found, use common string applying to all encoders.
experiment_string = field_trials.Lookup("WebRTC-GetEncoderInfoOverride");
}
ParseFieldTrial({&bitrate_limits, &requested_resolution_alignment_,
&apply_alignment_to_all_simulcast_layers_},
experiment_string);
resolution_bitrate_limits_ = ToResolutionBitrateLimits(bitrate_limits.Get());
}
std::optional<uint32_t> EncoderInfoSettings::requested_resolution_alignment()
const {
if (requested_resolution_alignment_ &&
requested_resolution_alignment_.Value() < 1) {
RTC_LOG(LS_WARNING) << "Unsupported alignment value, ignored.";
return std::nullopt;
}
return requested_resolution_alignment_.GetOptional();
}
EncoderInfoSettings::~EncoderInfoSettings() {}
SimulcastEncoderAdapterEncoderInfoSettings::
SimulcastEncoderAdapterEncoderInfoSettings(
const FieldTrialsView& field_trials)
: EncoderInfoSettings(
field_trials,
"WebRTC-SimulcastEncoderAdapter-GetEncoderInfoOverride") {}
LibvpxVp8EncoderInfoSettings::LibvpxVp8EncoderInfoSettings(
const FieldTrialsView& field_trials)
: EncoderInfoSettings(field_trials, "WebRTC-VP8-GetEncoderInfoOverride") {}
LibvpxVp9EncoderInfoSettings::LibvpxVp9EncoderInfoSettings(
const FieldTrialsView& field_trials)
: EncoderInfoSettings(field_trials, "WebRTC-VP9-GetEncoderInfoOverride") {}
LibaomAv1EncoderInfoSettings::LibaomAv1EncoderInfoSettings(
const FieldTrialsView& field_trials)
: EncoderInfoSettings(field_trials, "WebRTC-Av1-GetEncoderInfoOverride") {}
} // namespace webrtc