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cd013b1d59
- Add `WebRTC-Audio-OpusDecodeStereoByDefault` field trial - Behind that field trial, `AudioDecoderOpus::SdpToConfig` uses 2 instead of 1 as default number of channels when the `stereo` codec param is unspecified - Instead of wiring up `FieldTrialsView` to `SdpToConfig`, which requires API changes that break downstream projects, a change in `AudioDecoderOpus::Config` is made to signal when the number of channels is forced via SDP config Bug: webrtc:379996136 Change-Id: If70eb19bc7e3bc74dd0423610cb04ae33ea602fe Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/368860 Commit-Queue: Alessio Bazzica <alessiob@webrtc.org> Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org> Reviewed-by: Jakob Ivarsson <jakobi@webrtc.org> Cr-Commit-Position: refs/heads/main@{#43440}
99 lines
3 KiB
C++
99 lines
3 KiB
C++
/*
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* Copyright (c) 2017 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 "api/audio_codecs/opus/audio_decoder_opus.h"
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#include <map>
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#include <memory>
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#include <optional>
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#include <string>
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#include <utility>
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#include <vector>
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#include "absl/strings/match.h"
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#include "api/audio_codecs/audio_codec_pair_id.h"
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#include "api/audio_codecs/audio_decoder.h"
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#include "api/audio_codecs/audio_format.h"
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#include "modules/audio_coding/codecs/opus/audio_decoder_opus.h"
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#include "rtc_base/checks.h"
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namespace webrtc {
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namespace {
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int GetDefaultNumChannels(const FieldTrialsView& field_trials) {
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return field_trials.IsEnabled("WebRTC-Audio-OpusDecodeStereoByDefault") ? 2
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: 1;
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}
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} // namespace
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bool AudioDecoderOpus::Config::IsOk() const {
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if (sample_rate_hz != 16000 && sample_rate_hz != 48000) {
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// Unsupported sample rate. (libopus supports a few other rates as
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// well; we can add support for them when needed.)
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return false;
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}
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return !num_channels.has_value() || *num_channels == 1 || *num_channels == 2;
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}
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std::optional<AudioDecoderOpus::Config> AudioDecoderOpus::SdpToConfig(
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const SdpAudioFormat& format) {
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if (!absl::EqualsIgnoreCase(format.name, "opus") ||
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format.clockrate_hz != 48000 || format.num_channels != 2) {
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return std::nullopt;
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}
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Config config;
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// Parse the "stereo" codec parameter. If set, it overrides the default number
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// of channels.
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const auto stereo_param = format.parameters.find("stereo");
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if (stereo_param != format.parameters.end()) {
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if (stereo_param->second == "0") {
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config.num_channels = 1;
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} else if (stereo_param->second == "1") {
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config.num_channels = 2;
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} else {
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// Malformed stereo parameter.
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return std::nullopt;
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}
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}
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if (!config.IsOk()) {
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RTC_DCHECK_NOTREACHED();
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return std::nullopt;
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}
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return config;
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}
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void AudioDecoderOpus::AppendSupportedDecoders(
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std::vector<AudioCodecSpec>* specs) {
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AudioCodecInfo opus_info{48000, 1, 64000, 6000, 510000};
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opus_info.allow_comfort_noise = false;
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opus_info.supports_network_adaption = true;
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SdpAudioFormat opus_format(
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{"opus", 48000, 2, {{"minptime", "10"}, {"useinbandfec", "1"}}});
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specs->push_back({std::move(opus_format), opus_info});
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}
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std::unique_ptr<AudioDecoder> AudioDecoderOpus::MakeAudioDecoder(
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const Environment& env,
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Config config) {
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if (!config.IsOk()) {
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RTC_DCHECK_NOTREACHED();
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return nullptr;
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}
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return std::make_unique<AudioDecoderOpusImpl>(
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env.field_trials(),
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config.num_channels.value_or(GetDefaultNumChannels(env.field_trials())),
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config.sample_rate_hz);
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}
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} // namespace webrtc
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