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 <dcp/compose.h>
37 using std::shared_ptr;
38 using std::make_shared;
39 using boost::optional;
40 using namespace dcpomatic;
43 AudioDecoder::AudioDecoder (Decoder* parent, shared_ptr<const AudioContent> content, bool fast)
44 : DecoderPart (parent)
48 /* Set up _positions so that we have one for each stream */
49 for (auto i: content->streams ()) {
55 /** @param time_already_delayed true if the delay should not be added to time */
57 AudioDecoder::emit (shared_ptr<const Film> film, AudioStreamPtr stream, shared_ptr<const AudioBuffers> data, ContentTime time, bool time_already_delayed)
63 /* Amount of error we will tolerate on audio timestamps; see comment below.
64 * We'll use 1 24fps video frame at 48kHz as this seems to be roughly how
67 static Frame const slack_frames = 48000 / 24;
69 int const resampled_rate = _content->resampled_frame_rate(film);
70 if (!time_already_delayed) {
71 time += ContentTime::from_seconds (_content->delay() / 1000.0);
75 if (_positions[stream] == 0) {
76 /* This is the first data we have received since initialisation or seek. Set
77 the position based on the ContentTime that was given. After this first time
78 we just count samples unless the timestamp is more than slack_frames away
79 from where we think it should be. This is because ContentTimes seem to be
80 slightly unreliable from FFmpegDecoder (i.e. not sample accurate), but we still
81 need to obey them sometimes otherwise we get sync problems such as #1833.
83 if (_content->delay() > 0) {
84 /* Insert silence to give the delay */
85 silence (_content->delay ());
88 } else if (std::abs(_positions[stream] - time.frames_round(resampled_rate)) > slack_frames) {
91 "Reset audio position: was %1, new data at %2, slack: %3 frames",
93 time.frames_round(resampled_rate),
94 std::abs(_positions[stream] - time.frames_round(resampled_rate))
99 _positions[stream] = time.frames_round (resampled_rate);
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 silence (-_content->delay ());
194 AudioDecoder::silence (int milliseconds)
196 for (auto i: _content->streams()) {
197 int const samples = ContentTime::from_seconds(milliseconds / 1000.0).frames_round(i->frame_rate());
198 auto silence = make_shared<AudioBuffers>(i->channels(), samples);
199 silence->make_silent ();
200 Data (i, ContentAudio (silence, _positions[i]));