| /* |
| * Copyright (c) 2012 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/neteq/timestamp_scaler.h" |
| |
| #include "webrtc/modules/audio_coding/neteq/decoder_database.h" |
| #include "webrtc/system_wrappers/include/logging.h" |
| |
| namespace webrtc { |
| |
| void TimestampScaler::Reset() { |
| first_packet_received_ = false; |
| } |
| |
| void TimestampScaler::ToInternal(Packet* packet) { |
| if (!packet) { |
| return; |
| } |
| packet->header.timestamp = ToInternal(packet->header.timestamp, |
| packet->header.payloadType); |
| } |
| |
| void TimestampScaler::ToInternal(PacketList* packet_list) { |
| PacketList::iterator it; |
| for (it = packet_list->begin(); it != packet_list->end(); ++it) { |
| ToInternal(*it); |
| } |
| } |
| |
| uint32_t TimestampScaler::ToInternal(uint32_t external_timestamp, |
| uint8_t rtp_payload_type) { |
| const DecoderDatabase::DecoderInfo* info = |
| decoder_database_.GetDecoderInfo(rtp_payload_type); |
| if (!info) { |
| // Payload type is unknown. Do not scale. |
| return external_timestamp; |
| } |
| if (!(info->IsComfortNoise() || info->IsDtmf())) { |
| // Do not change the timestamp scaling settings for DTMF or CNG. |
| numerator_ = info->SampleRateHz(); |
| if (info->codec_type == NetEqDecoder::kDecoderArbitrary) { |
| // We have no format mapping for "arbitrary" external codecs, so we cannot |
| // support timestamp scaling of them. |
| denominator_ = numerator_; |
| } else { |
| denominator_ = info->GetFormat().clockrate_hz; |
| } |
| } |
| if (numerator_ != denominator_) { |
| // We have a scale factor != 1. |
| if (!first_packet_received_) { |
| external_ref_ = external_timestamp; |
| internal_ref_ = external_timestamp; |
| first_packet_received_ = true; |
| } |
| const int64_t external_diff = int64_t{external_timestamp} - external_ref_; |
| assert(denominator_ > 0); // Should not be possible. |
| external_ref_ = external_timestamp; |
| internal_ref_ += (external_diff * numerator_) / denominator_; |
| return internal_ref_; |
| } else { |
| // No scaling. |
| return external_timestamp; |
| } |
| } |
| |
| |
| uint32_t TimestampScaler::ToExternal(uint32_t internal_timestamp) const { |
| if (!first_packet_received_ || (numerator_ == denominator_)) { |
| // Not initialized, or scale factor is 1. |
| return internal_timestamp; |
| } else { |
| const int64_t internal_diff = int64_t{internal_timestamp} - internal_ref_; |
| assert(numerator_ > 0); // Should not be possible. |
| // Do not update references in this method. |
| // Switch |denominator_| and |numerator_| to convert the other way. |
| return external_ref_ + (internal_diff * denominator_) / numerator_; |
| } |
| } |
| |
| } // namespace webrtc |