2 Copyright (C) 2012-2021 Carl Hetherington <cth@carlh.net>
4 This file is part of DCP-o-matic.
6 DCP-o-matic is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 DCP-o-matic is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
22 #include "audio_decoder.h"
23 #include "audio_buffers.h"
24 #include "audio_content.h"
25 #include "dcpomatic_log.h"
27 #include "resampler.h"
28 #include "compose.hpp"
35 using std::shared_ptr;
36 using std::make_shared;
37 using boost::optional;
38 using namespace dcpomatic;
41 AudioDecoder::AudioDecoder (Decoder* parent, shared_ptr<const AudioContent> content, bool fast)
42 : DecoderPart (parent)
46 /* Set up _positions so that we have one for each stream */
47 for (auto i: content->streams ()) {
53 /** @param time_already_delayed true if the delay should not be added to time */
55 AudioDecoder::emit (shared_ptr<const Film> film, AudioStreamPtr stream, shared_ptr<const AudioBuffers> data, ContentTime time, bool time_already_delayed)
61 /* Amount of error we will tolerate on audio timestamps; see comment below.
62 * We'll use 1 24fps video frame at 48kHz as this seems to be roughly how
65 static Frame const slack_frames = 48000 / 24;
67 int const resampled_rate = _content->resampled_frame_rate(film);
68 if (!time_already_delayed) {
69 time += ContentTime::from_seconds (_content->delay() / 1000.0);
72 /* first_since_seek is set to true if this is the first data we have
73 received since initialisation or seek. We'll set the position based
74 on the ContentTime that was given. After this first time we just
75 count samples unless the timestamp is more than slack_frames away
76 from where we think it should be. This is because ContentTimes seem
77 to be slightly unreliable from FFmpegDecoder (i.e. not sample
78 accurate), but we still need to obey them sometimes otherwise we get
79 sync problems such as #1833.
82 auto const first_since_seek = _positions[stream] == 0;
83 auto const need_reset = !first_since_seek && (std::abs(_positions[stream] - time.frames_round(resampled_rate)) > slack_frames);
87 "Reset audio position: was %1, new data at %2, slack: %3 frames",
89 time.frames_round(resampled_rate),
90 std::abs(_positions[stream] - time.frames_round(resampled_rate))
94 if (first_since_seek || need_reset) {
95 _positions[stream] = time.frames_round (resampled_rate);
98 if (first_since_seek && _content->delay() > 0) {
99 silence (stream, _content->delay());
102 shared_ptr<Resampler> resampler;
103 auto i = _resamplers.find(stream);
104 if (i != _resamplers.end()) {
105 resampler = i->second;
107 if (stream->frame_rate() != resampled_rate) {
109 "Creating new resampler from %1 to %2 with %3 channels",
110 stream->frame_rate(),
115 resampler = make_shared<Resampler>(stream->frame_rate(), resampled_rate, stream->channels());
117 resampler->set_fast ();
119 _resamplers[stream] = resampler;
124 auto ro = resampler->run (data);
125 if (ro->frames() == 0) {
131 Data(stream, ContentAudio (data, _positions[stream]));
132 _positions[stream] += data->frames();
136 /** @return Time just after the last thing that was emitted from a given stream */
138 AudioDecoder::stream_position (shared_ptr<const Film> film, AudioStreamPtr stream) const
140 auto i = _positions.find (stream);
141 DCPOMATIC_ASSERT (i != _positions.end ());
142 return ContentTime::from_frames (i->second, _content->resampled_frame_rate(film));
146 boost::optional<ContentTime>
147 AudioDecoder::position (shared_ptr<const Film> film) const
149 optional<ContentTime> p;
150 for (auto i: _positions) {
151 auto const ct = stream_position (film, i.first);
162 AudioDecoder::seek ()
164 for (auto i: _resamplers) {
169 for (auto& i: _positions) {
176 AudioDecoder::flush ()
178 for (auto const& i: _resamplers) {
179 auto ro = i.second->flush ();
180 if (ro->frames() > 0) {
181 Data (i.first, ContentAudio (ro, _positions[i.first]));
182 _positions[i.first] += ro->frames();
186 if (_content->delay() < 0) {
187 /* Finish off with the gap caused by the delay */
188 for (auto stream: _content->streams()) {
189 silence (stream, -_content->delay());
196 AudioDecoder::silence (AudioStreamPtr stream, int milliseconds)
198 int const samples = ContentTime::from_seconds(milliseconds / 1000.0).frames_round(stream->frame_rate());
199 auto silence = make_shared<AudioBuffers>(stream->channels(), samples);
200 silence->make_silent ();
201 Data (stream, ContentAudio(silence, _positions[stream]));