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"
29 using std::stringstream;
33 using boost::optional;
34 using boost::shared_ptr;
36 AudioDecoder::AudioDecoder (shared_ptr<const AudioContent> content)
37 : _audio_content (content)
39 if (content->output_audio_frame_rate() != content->content_audio_frame_rate() && content->audio_channels ()) {
40 _resampler.reset (new Resampler (content->content_audio_frame_rate(), content->output_audio_frame_rate(), content->audio_channels ()));
44 /** Audio timestamping is made hard by many factors, but the final nail in the coffin is resampling.
45 * We have to assume that we are feeding continuous data into the resampler, and so we get continuous
46 * data out. Hence we do the timestamping here, post-resampler, just by counting samples.
48 * The time is passed in here so that after a seek we can set up our _audio_position. The
49 * time is ignored once this has been done.
52 AudioDecoder::audio (shared_ptr<const AudioBuffers> data, ContentTime time)
55 data = _resampler->run (data);
58 if (!_audio_position) {
59 _audio_position = time;
62 _pending.push_back (shared_ptr<DecodedAudio> (new DecodedAudio (_audio_position.get (), data)));
63 _audio_position = _audio_position.get() + ContentTime (data->frames (), _audio_content->output_audio_frame_rate ());
67 AudioDecoder::flush ()
73 shared_ptr<const AudioBuffers> b = _resampler->flush ();
75 _pending.push_back (shared_ptr<DecodedAudio> (new DecodedAudio (_audio_position.get (), b)));
76 _audio_position = _audio_position.get() + ContentTime (b->frames (), _audio_content->output_audio_frame_rate ());
81 AudioDecoder::seek (ContentTime, bool)
83 _audio_position.reset ();