| /* |
| * Copyright (c) 2017 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 "api/audio_codecs/opus/audio_decoder_opus.h" |
| |
| #include <map> |
| #include <memory> |
| #include <optional> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/strings/match.h" |
| #include "api/audio_codecs/audio_codec_pair_id.h" |
| #include "api/audio_codecs/audio_decoder.h" |
| #include "api/audio_codecs/audio_format.h" |
| #include "modules/audio_coding/codecs/opus/audio_decoder_opus.h" |
| #include "rtc_base/checks.h" |
| |
| namespace webrtc { |
| namespace { |
| |
| int GetDefaultNumChannels(const FieldTrialsView& field_trials) { |
| return field_trials.IsEnabled("WebRTC-Audio-OpusDecodeStereoByDefault") ? 2 |
| : 1; |
| } |
| |
| } // namespace |
| |
| bool AudioDecoderOpus::Config::IsOk() const { |
| if (sample_rate_hz != 16000 && sample_rate_hz != 48000) { |
| // Unsupported sample rate. (libopus supports a few other rates as |
| // well; we can add support for them when needed.) |
| return false; |
| } |
| return !num_channels.has_value() || *num_channels == 1 || *num_channels == 2; |
| } |
| |
| std::optional<AudioDecoderOpus::Config> AudioDecoderOpus::SdpToConfig( |
| const SdpAudioFormat& format) { |
| if (!absl::EqualsIgnoreCase(format.name, "opus") || |
| format.clockrate_hz != 48000 || format.num_channels != 2) { |
| return std::nullopt; |
| } |
| |
| Config config; |
| |
| // Parse the "stereo" codec parameter. If set, it overrides the default number |
| // of channels. |
| const auto stereo_param = format.parameters.find("stereo"); |
| if (stereo_param != format.parameters.end()) { |
| if (stereo_param->second == "0") { |
| config.num_channels = 1; |
| } else if (stereo_param->second == "1") { |
| config.num_channels = 2; |
| } else { |
| // Malformed stereo parameter. |
| return std::nullopt; |
| } |
| } |
| |
| if (!config.IsOk()) { |
| RTC_DCHECK_NOTREACHED(); |
| return std::nullopt; |
| } |
| return config; |
| } |
| |
| void AudioDecoderOpus::AppendSupportedDecoders( |
| std::vector<AudioCodecSpec>* specs) { |
| AudioCodecInfo opus_info{48000, 1, 64000, 6000, 510000}; |
| opus_info.allow_comfort_noise = false; |
| opus_info.supports_network_adaption = true; |
| SdpAudioFormat opus_format( |
| {"opus", 48000, 2, {{"minptime", "10"}, {"useinbandfec", "1"}}}); |
| specs->push_back({std::move(opus_format), opus_info}); |
| } |
| |
| std::unique_ptr<AudioDecoder> AudioDecoderOpus::MakeAudioDecoder( |
| const Environment& env, |
| Config config) { |
| if (!config.IsOk()) { |
| RTC_DCHECK_NOTREACHED(); |
| return nullptr; |
| } |
| return std::make_unique<AudioDecoderOpusImpl>( |
| env.field_trials(), |
| config.num_channels.value_or(GetDefaultNumChannels(env.field_trials())), |
| config.sample_rate_hz); |
| } |
| |
| } // namespace webrtc |