diff options
Diffstat (limited to 'third_party/libwebrtc/modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.cc')
-rw-r--r-- | third_party/libwebrtc/modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.cc | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.cc b/third_party/libwebrtc/modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.cc new file mode 100644 index 0000000000..9fbf42ceeb --- /dev/null +++ b/third_party/libwebrtc/modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.cc @@ -0,0 +1,151 @@ +/* + * 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 "modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.h" + +#include <algorithm> +#include <cstdint> + +#include "modules/audio_coding/codecs/ilbc/ilbc.h" +#include "rtc_base/checks.h" +#include "rtc_base/numerics/safe_conversions.h" + +namespace webrtc { + +namespace { + +const int kSampleRateHz = 8000; + +int GetIlbcBitrate(int ptime) { + switch (ptime) { + case 20: + case 40: + // 38 bytes per frame of 20 ms => 15200 bits/s. + return 15200; + case 30: + case 60: + // 50 bytes per frame of 30 ms => (approx) 13333 bits/s. + return 13333; + default: + RTC_CHECK_NOTREACHED(); + } +} + +} // namespace + +AudioEncoderIlbcImpl::AudioEncoderIlbcImpl(const AudioEncoderIlbcConfig& config, + int payload_type) + : frame_size_ms_(config.frame_size_ms), + payload_type_(payload_type), + num_10ms_frames_per_packet_( + static_cast<size_t>(config.frame_size_ms / 10)), + encoder_(nullptr) { + RTC_CHECK(config.IsOk()); + Reset(); +} + +AudioEncoderIlbcImpl::~AudioEncoderIlbcImpl() { + RTC_CHECK_EQ(0, WebRtcIlbcfix_EncoderFree(encoder_)); +} + +int AudioEncoderIlbcImpl::SampleRateHz() const { + return kSampleRateHz; +} + +size_t AudioEncoderIlbcImpl::NumChannels() const { + return 1; +} + +size_t AudioEncoderIlbcImpl::Num10MsFramesInNextPacket() const { + return num_10ms_frames_per_packet_; +} + +size_t AudioEncoderIlbcImpl::Max10MsFramesInAPacket() const { + return num_10ms_frames_per_packet_; +} + +int AudioEncoderIlbcImpl::GetTargetBitrate() const { + return GetIlbcBitrate(rtc::dchecked_cast<int>(num_10ms_frames_per_packet_) * + 10); +} + +AudioEncoder::EncodedInfo AudioEncoderIlbcImpl::EncodeImpl( + uint32_t rtp_timestamp, + rtc::ArrayView<const int16_t> audio, + rtc::Buffer* encoded) { + // Save timestamp if starting a new packet. + if (num_10ms_frames_buffered_ == 0) + first_timestamp_in_buffer_ = rtp_timestamp; + + // Buffer input. + std::copy(audio.cbegin(), audio.cend(), + input_buffer_ + kSampleRateHz / 100 * num_10ms_frames_buffered_); + + // If we don't yet have enough buffered input for a whole packet, we're done + // for now. + if (++num_10ms_frames_buffered_ < num_10ms_frames_per_packet_) { + return EncodedInfo(); + } + + // Encode buffered input. + RTC_DCHECK_EQ(num_10ms_frames_buffered_, num_10ms_frames_per_packet_); + num_10ms_frames_buffered_ = 0; + size_t encoded_bytes = encoded->AppendData( + RequiredOutputSizeBytes(), [&](rtc::ArrayView<uint8_t> encoded) { + const int r = WebRtcIlbcfix_Encode( + encoder_, input_buffer_, + kSampleRateHz / 100 * num_10ms_frames_per_packet_, encoded.data()); + RTC_CHECK_GE(r, 0); + + return static_cast<size_t>(r); + }); + + RTC_DCHECK_EQ(encoded_bytes, RequiredOutputSizeBytes()); + + EncodedInfo info; + info.encoded_bytes = encoded_bytes; + info.encoded_timestamp = first_timestamp_in_buffer_; + info.payload_type = payload_type_; + info.encoder_type = CodecType::kIlbc; + return info; +} + +void AudioEncoderIlbcImpl::Reset() { + if (encoder_) + RTC_CHECK_EQ(0, WebRtcIlbcfix_EncoderFree(encoder_)); + RTC_CHECK_EQ(0, WebRtcIlbcfix_EncoderCreate(&encoder_)); + const int encoder_frame_size_ms = + frame_size_ms_ > 30 ? frame_size_ms_ / 2 : frame_size_ms_; + RTC_CHECK_EQ(0, WebRtcIlbcfix_EncoderInit(encoder_, encoder_frame_size_ms)); + num_10ms_frames_buffered_ = 0; +} + +absl::optional<std::pair<TimeDelta, TimeDelta>> +AudioEncoderIlbcImpl::GetFrameLengthRange() const { + return {{TimeDelta::Millis(num_10ms_frames_per_packet_ * 10), + TimeDelta::Millis(num_10ms_frames_per_packet_ * 10)}}; +} + +size_t AudioEncoderIlbcImpl::RequiredOutputSizeBytes() const { + switch (num_10ms_frames_per_packet_) { + case 2: + return 38; + case 3: + return 50; + case 4: + return 2 * 38; + case 6: + return 2 * 50; + default: + RTC_CHECK_NOTREACHED(); + } +} + +} // namespace webrtc |