audio_encoder_g711.cc (3436B)
1 /* 2 * Copyright (c) 2017 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "api/audio_codecs/g711/audio_encoder_g711.h" 12 13 #include <cstddef> 14 #include <initializer_list> 15 #include <map> 16 #include <memory> 17 #include <optional> 18 #include <vector> 19 20 #include "absl/strings/match.h" 21 #include "api/audio_codecs/audio_codec_pair_id.h" 22 #include "api/audio_codecs/audio_encoder.h" 23 #include "api/audio_codecs/audio_format.h" 24 #include "api/field_trials_view.h" 25 #include "modules/audio_coding/codecs/g711/audio_encoder_pcm.h" 26 #include "rtc_base/checks.h" 27 #include "rtc_base/numerics/safe_conversions.h" 28 #include "rtc_base/numerics/safe_minmax.h" 29 #include "rtc_base/string_to_number.h" 30 31 namespace webrtc { 32 33 std::optional<AudioEncoderG711::Config> AudioEncoderG711::SdpToConfig( 34 const SdpAudioFormat& format) { 35 const bool is_pcmu = absl::EqualsIgnoreCase(format.name, "PCMU"); 36 const bool is_pcma = absl::EqualsIgnoreCase(format.name, "PCMA"); 37 if (format.clockrate_hz == 8000 && format.num_channels >= 1 && 38 (is_pcmu || is_pcma)) { 39 Config config; 40 config.type = is_pcmu ? Config::Type::kPcmU : Config::Type::kPcmA; 41 config.num_channels = dchecked_cast<int>(format.num_channels); 42 config.frame_size_ms = 20; 43 auto ptime_iter = format.parameters.find("ptime"); 44 if (ptime_iter != format.parameters.end()) { 45 const auto ptime = StringToNumber<int>(ptime_iter->second); 46 if (ptime && *ptime > 0) { 47 config.frame_size_ms = SafeClamp(10 * (*ptime / 10), 10, 60); 48 } 49 } 50 if (!config.IsOk()) { 51 RTC_DCHECK_NOTREACHED(); 52 return std::nullopt; 53 } 54 return config; 55 } else { 56 return std::nullopt; 57 } 58 } 59 60 void AudioEncoderG711::AppendSupportedEncoders( 61 std::vector<AudioCodecSpec>* specs) { 62 for (const char* type : {"PCMU", "PCMA"}) { 63 specs->push_back({{type, 8000, 1}, {8000, 1, 64000}}); 64 } 65 } 66 67 AudioCodecInfo AudioEncoderG711::QueryAudioEncoder(const Config& config) { 68 RTC_DCHECK(config.IsOk()); 69 return {8000, dchecked_cast<size_t>(config.num_channels), 70 64000 * config.num_channels}; 71 } 72 73 std::unique_ptr<AudioEncoder> AudioEncoderG711::MakeAudioEncoder( 74 const Config& config, 75 int payload_type, 76 std::optional<AudioCodecPairId> /*codec_pair_id*/, 77 const FieldTrialsView* /* field_trials */) { 78 if (!config.IsOk()) { 79 RTC_DCHECK_NOTREACHED(); 80 return nullptr; 81 } 82 switch (config.type) { 83 case Config::Type::kPcmU: { 84 AudioEncoderPcmU::Config impl_config; 85 impl_config.num_channels = config.num_channels; 86 impl_config.frame_size_ms = config.frame_size_ms; 87 impl_config.payload_type = payload_type; 88 return std::make_unique<AudioEncoderPcmU>(impl_config); 89 } 90 case Config::Type::kPcmA: { 91 AudioEncoderPcmA::Config impl_config; 92 impl_config.num_channels = config.num_channels; 93 impl_config.frame_size_ms = config.frame_size_ms; 94 impl_config.payload_type = payload_type; 95 return std::make_unique<AudioEncoderPcmA>(impl_config); 96 } 97 default: { 98 RTC_DCHECK_NOTREACHED(); 99 return nullptr; 100 } 101 } 102 } 103 104 } // namespace webrtc