henrik.lundin@webrtc.org | d94659d | 2013-01-29 12:09:21 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2012 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 "webrtc/modules/audio_coding/neteq4/timestamp_scaler.h" |
| 12 | |
| 13 | #include "webrtc/modules/audio_coding/neteq4/decoder_database.h" |
| 14 | #include "webrtc/system_wrappers/interface/logging.h" |
| 15 | |
| 16 | namespace webrtc { |
| 17 | |
| 18 | void TimestampScaler::ToInternal(Packet* packet) { |
| 19 | if (!packet) { |
| 20 | return; |
| 21 | } |
| 22 | packet->header.timestamp = ToInternal(packet->header.timestamp, |
| 23 | packet->header.payloadType); |
| 24 | } |
| 25 | |
| 26 | void TimestampScaler::ToInternal(PacketList* packet_list) { |
| 27 | PacketList::iterator it; |
| 28 | for (it = packet_list->begin(); it != packet_list->end(); ++it) { |
| 29 | ToInternal(*it); |
| 30 | } |
| 31 | } |
| 32 | |
| 33 | uint32_t TimestampScaler::ToInternal(uint32_t external_timestamp, |
| 34 | uint8_t rtp_payload_type) { |
| 35 | const DecoderDatabase::DecoderInfo* info = |
| 36 | decoder_database_.GetDecoderInfo(rtp_payload_type); |
| 37 | if (!info) { |
| 38 | // Payload type is unknown. Do not scale. |
| 39 | return external_timestamp; |
| 40 | } |
| 41 | switch (info->codec_type) { |
| 42 | case kDecoderG722: |
| 43 | case kDecoderG722_2ch: { |
| 44 | // Use timestamp scaling with factor 2 (two output samples per RTP |
| 45 | // timestamp). |
| 46 | numerator_ = 2; |
| 47 | denominator_ = 1; |
| 48 | break; |
| 49 | } |
| 50 | case kDecoderOpus: |
| 51 | case kDecoderOpus_2ch: |
henrik.lundin@webrtc.org | ac59dba | 2013-01-31 09:55:24 +0000 | [diff] [blame] | 52 | case kDecoderISACfb: |
henrik.lundin@webrtc.org | d94659d | 2013-01-29 12:09:21 +0000 | [diff] [blame] | 53 | case kDecoderCNGswb48kHz: { |
| 54 | // Use timestamp scaling with factor 2/3 (32 kHz sample rate, but RTP |
| 55 | // timestamps run on 48 kHz). |
| 56 | // TODO(tlegrand): Remove scaling for kDecoderCNGswb48kHz once ACM has |
| 57 | // full 48 kHz support. |
| 58 | numerator_ = 2; |
| 59 | denominator_ = 3; |
| 60 | } |
| 61 | case kDecoderAVT: |
| 62 | case kDecoderCNGnb: |
| 63 | case kDecoderCNGwb: |
| 64 | case kDecoderCNGswb32kHz: { |
| 65 | // Do not change the timestamp scaling settings for DTMF or CNG. |
| 66 | break; |
| 67 | } |
| 68 | default: { |
| 69 | // Do not use timestamp scaling for any other codec. |
| 70 | numerator_ = 1; |
| 71 | denominator_ = 1; |
| 72 | break; |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | if (!(numerator_ == 1 && denominator_ == 1)) { |
| 77 | // We have a scale factor != 1. |
| 78 | if (!first_packet_received_) { |
| 79 | external_ref_ = external_timestamp; |
| 80 | internal_ref_ = external_timestamp; |
| 81 | first_packet_received_ = true; |
| 82 | } |
| 83 | int32_t external_diff = external_timestamp - external_ref_; |
| 84 | assert(denominator_ > 0); // Should not be possible. |
| 85 | external_ref_ = external_timestamp; |
| 86 | internal_ref_ += (external_diff * numerator_) / denominator_; |
| 87 | LOG(LS_VERBOSE) << "Converting timestamp: " << external_timestamp << |
| 88 | " -> " << internal_ref_; |
| 89 | return internal_ref_; |
| 90 | } else { |
| 91 | // No scaling. |
| 92 | return external_timestamp; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | |
| 97 | uint32_t TimestampScaler::ToExternal(uint32_t internal_timestamp) const { |
| 98 | if (!first_packet_received_ || (numerator_ == 1 && denominator_ == 1)) { |
| 99 | // Not initialized, or scale factor is 1. |
| 100 | return internal_timestamp; |
| 101 | } else { |
| 102 | int32_t internal_diff = internal_timestamp - internal_ref_; |
| 103 | assert(numerator_ > 0); // Should not be possible. |
| 104 | // Do not update references in this method. |
| 105 | // Switch |denominator_| and |numerator_| to convert the other way. |
| 106 | return external_ref_ + (internal_diff * denominator_) / numerator_; |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | } // namespace webrtc |