2 Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include "audio_decoder.h"
21 #include "audio_buffers.h"
22 #include "exceptions.h"
24 #include "resampler.h"
30 using std::stringstream;
34 using boost::optional;
35 using boost::shared_ptr;
37 AudioDecoder::AudioDecoder (shared_ptr<const Film> film, shared_ptr<const AudioContent> content)
39 , _audio_content (content)
41 if (content->output_audio_frame_rate() != content->content_audio_frame_rate() && content->audio_channels ()) {
42 _resampler.reset (new Resampler (content->content_audio_frame_rate(), content->output_audio_frame_rate(), content->audio_channels ()));
46 /** Audio timestamping is made hard by many factors, but the final nail in the coffin is resampling.
47 * We have to assume that we are feeding continuous data into the resampler, and so we get continuous
48 * data out. Hence we do the timestamping here, post-resampler, just by counting samples.
50 * The time is passed in here so that after a seek we can set up our _audio_position. The
51 * time is ignored once this has been done.
54 AudioDecoder::audio (shared_ptr<const AudioBuffers> data, ContentTime time)
57 data = _resampler->run (data);
60 if (!_audio_position) {
61 shared_ptr<const Film> film = _film.lock ();
63 FrameRateChange frc = film->active_frame_rate_change (_audio_content->position ());
64 _audio_position = (double (time) / frc.speed_up) * film->audio_frame_rate() / TIME_HZ;
67 _pending.push_back (shared_ptr<DecodedAudio> (new DecodedAudio (data, _audio_position.get ())));
68 _audio_position = _audio_position.get() + data->frames ();
72 AudioDecoder::flush ()
78 shared_ptr<const AudioBuffers> b = _resampler->flush ();
80 _pending.push_back (shared_ptr<DecodedAudio> (new DecodedAudio (b, _audio_position.get ())));
81 _audio_position = _audio_position.get() + b->frames ();
86 AudioDecoder::seek (ContentTime, bool)
88 _audio_position.reset ();