| /* |
| * Copyright (c) 2014 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 "webrtc/modules/audio_coding/codecs/opus/interface/audio_encoder_opus.h" |
| |
| #include "webrtc/base/checks.h" |
| #include "webrtc/modules/audio_coding/codecs/opus/interface/opus_interface.h" |
| |
| namespace webrtc { |
| |
| namespace { |
| |
| const int kMinBitrateBps = 500; |
| const int kMaxBitrateBps = 512000; |
| |
| // TODO(tlegrand): Remove this code when we have proper APIs to set the |
| // complexity at a higher level. |
| #if defined(WEBRTC_ANDROID) || defined(WEBRTC_IOS) || defined(WEBRTC_ARCH_ARM) |
| // If we are on Android, iOS and/or ARM, use a lower complexity setting as |
| // default, to save encoder complexity. |
| const int kDefaultComplexity = 5; |
| #else |
| const int kDefaultComplexity = 9; |
| #endif |
| |
| // We always encode at 48 kHz. |
| const int kSampleRateHz = 48000; |
| |
| int16_t ClampInt16(size_t x) { |
| return static_cast<int16_t>( |
| std::min(x, static_cast<size_t>(std::numeric_limits<int16_t>::max()))); |
| } |
| |
| int16_t CastInt16(size_t x) { |
| DCHECK_LE(x, static_cast<size_t>(std::numeric_limits<int16_t>::max())); |
| return static_cast<int16_t>(x); |
| } |
| |
| } // namespace |
| |
| AudioEncoderOpus::Config::Config() |
| : frame_size_ms(20), |
| num_channels(1), |
| payload_type(120), |
| application(kVoip), |
| bitrate_bps(64000), |
| fec_enabled(false), |
| max_playback_rate_hz(48000), |
| complexity(kDefaultComplexity) { |
| } |
| |
| bool AudioEncoderOpus::Config::IsOk() const { |
| if (frame_size_ms <= 0 || frame_size_ms % 10 != 0) |
| return false; |
| if (num_channels != 1 && num_channels != 2) |
| return false; |
| if (bitrate_bps < kMinBitrateBps || bitrate_bps > kMaxBitrateBps) |
| return false; |
| if (complexity < 0 || complexity > 10) |
| return false; |
| return true; |
| } |
| |
| AudioEncoderOpus::AudioEncoderOpus(const Config& config) |
| : num_10ms_frames_per_packet_( |
| rtc::CheckedDivExact(config.frame_size_ms, 10)), |
| num_channels_(config.num_channels), |
| payload_type_(config.payload_type), |
| application_(config.application), |
| samples_per_10ms_frame_(rtc::CheckedDivExact(kSampleRateHz, 100) * |
| num_channels_), |
| packet_loss_rate_(0.0) { |
| CHECK(config.IsOk()); |
| input_buffer_.reserve(num_10ms_frames_per_packet_ * samples_per_10ms_frame_); |
| CHECK_EQ(0, WebRtcOpus_EncoderCreate(&inst_, num_channels_, application_)); |
| SetTargetBitrate(config.bitrate_bps); |
| if (config.fec_enabled) { |
| CHECK_EQ(0, WebRtcOpus_EnableFec(inst_)); |
| } else { |
| CHECK_EQ(0, WebRtcOpus_DisableFec(inst_)); |
| } |
| CHECK_EQ(0, |
| WebRtcOpus_SetMaxPlaybackRate(inst_, config.max_playback_rate_hz)); |
| CHECK_EQ(0, WebRtcOpus_SetComplexity(inst_, config.complexity)); |
| |
| } |
| |
| AudioEncoderOpus::~AudioEncoderOpus() { |
| CHECK_EQ(0, WebRtcOpus_EncoderFree(inst_)); |
| } |
| |
| int AudioEncoderOpus::sample_rate_hz() const { |
| return kSampleRateHz; |
| } |
| |
| int AudioEncoderOpus::num_channels() const { |
| return num_channels_; |
| } |
| |
| int AudioEncoderOpus::Num10MsFramesInNextPacket() const { |
| return num_10ms_frames_per_packet_; |
| } |
| |
| int AudioEncoderOpus::Max10MsFramesInAPacket() const { |
| return num_10ms_frames_per_packet_; |
| } |
| |
| void AudioEncoderOpus::SetTargetBitrate(int bits_per_second) { |
| CHECK_EQ(WebRtcOpus_SetBitRate( |
| inst_, std::max(std::min(bits_per_second, kMaxBitrateBps), |
| kMinBitrateBps)), |
| 0); |
| } |
| |
| void AudioEncoderOpus::SetProjectedPacketLossRate(double fraction) { |
| DCHECK_GE(fraction, 0.0); |
| DCHECK_LE(fraction, 1.0); |
| // Optimize the loss rate to configure Opus. Basically, optimized loss rate is |
| // the input loss rate rounded down to various levels, because a robustly good |
| // audio quality is achieved by lowering the packet loss down. |
| // Additionally, to prevent toggling, margins are used, i.e., when jumping to |
| // a loss rate from below, a higher threshold is used than jumping to the same |
| // level from above. |
| const double kPacketLossRate20 = 0.20; |
| const double kPacketLossRate10 = 0.10; |
| const double kPacketLossRate5 = 0.05; |
| const double kPacketLossRate1 = 0.01; |
| const double kLossRate20Margin = 0.02; |
| const double kLossRate10Margin = 0.01; |
| const double kLossRate5Margin = 0.01; |
| double opt_loss_rate; |
| if (fraction >= |
| kPacketLossRate20 + |
| kLossRate20Margin * |
| (kPacketLossRate20 - packet_loss_rate_ > 0 ? 1 : -1)) { |
| opt_loss_rate = kPacketLossRate20; |
| } else if (fraction >= |
| kPacketLossRate10 + |
| kLossRate10Margin * |
| (kPacketLossRate10 - packet_loss_rate_ > 0 ? 1 : -1)) { |
| opt_loss_rate = kPacketLossRate10; |
| } else if (fraction >= |
| kPacketLossRate5 + |
| kLossRate5Margin * |
| (kPacketLossRate5 - packet_loss_rate_ > 0 ? 1 : -1)) { |
| opt_loss_rate = kPacketLossRate5; |
| } else if (fraction >= kPacketLossRate1) { |
| opt_loss_rate = kPacketLossRate1; |
| } else { |
| opt_loss_rate = 0; |
| } |
| |
| if (packet_loss_rate_ != opt_loss_rate) { |
| // Ask the encoder to change the target packet loss rate. |
| CHECK_EQ(WebRtcOpus_SetPacketLossRate( |
| inst_, static_cast<int32_t>(opt_loss_rate * 100 + .5)), |
| 0); |
| packet_loss_rate_ = opt_loss_rate; |
| } |
| } |
| |
| bool AudioEncoderOpus::EncodeInternal(uint32_t rtp_timestamp, |
| const int16_t* audio, |
| size_t max_encoded_bytes, |
| uint8_t* encoded, |
| EncodedInfo* info) { |
| if (input_buffer_.empty()) |
| first_timestamp_in_buffer_ = rtp_timestamp; |
| input_buffer_.insert(input_buffer_.end(), audio, |
| audio + samples_per_10ms_frame_); |
| if (input_buffer_.size() < (static_cast<size_t>(num_10ms_frames_per_packet_) * |
| samples_per_10ms_frame_)) { |
| info->encoded_bytes = 0; |
| return true; |
| } |
| CHECK_EQ(input_buffer_.size(), |
| static_cast<size_t>(num_10ms_frames_per_packet_) * |
| samples_per_10ms_frame_); |
| int16_t r = WebRtcOpus_Encode( |
| inst_, &input_buffer_[0], |
| rtc::CheckedDivExact(CastInt16(input_buffer_.size()), |
| static_cast<int16_t>(num_channels_)), |
| ClampInt16(max_encoded_bytes), encoded); |
| input_buffer_.clear(); |
| if (r < 0) |
| return false; |
| info->encoded_bytes = r; |
| info->encoded_timestamp = first_timestamp_in_buffer_; |
| info->payload_type = payload_type_; |
| return true; |
| } |
| |
| } // namespace webrtc |