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);
73 if (_positions[stream] == 0) {
74 /* This is the first data we have received since initialisation or seek. Set
75 the position based on the ContentTime that was given. After this first time
76 we just count samples unless the timestamp is more than slack_frames away
77 from where we think it should be. This is because ContentTimes seem to be
78 slightly unreliable from FFmpegDecoder (i.e. not sample accurate), but we still
79 need to obey them sometimes otherwise we get sync problems such as #1833.
81 if (_content->delay() > 0) {
82 /* Insert silence to give the delay */
83 silence (_content->delay ());
86 } else if (std::abs(_positions[stream] - time.frames_round(resampled_rate)) > slack_frames) {
89 "Reset audio position: was %1, new data at %2, slack: %3 frames",
91 time.frames_round(resampled_rate),
92 std::abs(_positions[stream] - time.frames_round(resampled_rate))
97 _positions[stream] = time.frames_round (resampled_rate);
100 shared_ptr<Resampler> resampler;
101 auto i = _resamplers.find(stream);
102 if (i != _resamplers.end()) {
103 resampler = i->second;
105 if (stream->frame_rate() != resampled_rate) {
107 "Creating new resampler from %1 to %2 with %3 channels",
108 stream->frame_rate(),
113 resampler = make_shared<Resampler>(stream->frame_rate(), resampled_rate, stream->channels());
115 resampler->set_fast ();
117 _resamplers[stream] = resampler;
122 auto ro = resampler->run (data);
123 if (ro->frames() == 0) {
129 Data(stream, ContentAudio (data, _positions[stream]));
130 _positions[stream] += data->frames();
134 /** @return Time just after the last thing that was emitted from a given stream */
136 AudioDecoder::stream_position (shared_ptr<const Film> film, AudioStreamPtr stream) const
138 auto i = _positions.find (stream);
139 DCPOMATIC_ASSERT (i != _positions.end ());
140 return ContentTime::from_frames (i->second, _content->resampled_frame_rate(film));
144 boost::optional<ContentTime>
145 AudioDecoder::position (shared_ptr<const Film> film) const
147 optional<ContentTime> p;
148 for (auto i: _positions) {
149 auto const ct = stream_position (film, i.first);
160 AudioDecoder::seek ()
162 for (auto i: _resamplers) {
167 for (auto& i: _positions) {
174 AudioDecoder::flush ()
176 for (auto const& i: _resamplers) {
177 auto ro = i.second->flush ();
178 if (ro->frames() > 0) {
179 Data (i.first, ContentAudio (ro, _positions[i.first]));
180 _positions[i.first] += ro->frames();
184 if (_content->delay() < 0) {
185 /* Finish off with the gap caused by the delay */
186 silence (-_content->delay ());
192 AudioDecoder::silence (int milliseconds)
194 for (auto i: _content->streams()) {
195 int const samples = ContentTime::from_seconds(milliseconds / 1000.0).frames_round(i->frame_rate());
196 auto silence = make_shared<AudioBuffers>(i->channels(), samples);
197 silence->make_silent ();
198 Data (i, ContentAudio (silence, _positions[i]));