2 Copyright (C) 2013-2016 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_merger.h"
21 #include "dcpomatic_time.h"
28 using boost::shared_ptr;
30 AudioMerger::AudioMerger (int channels, int frame_rate)
31 : _buffers (new AudioBuffers (channels, 0))
33 , _frame_rate (frame_rate)
38 /** Pull audio up to a given time; after this call, no more data can be pushed
39 * before the specified time.
41 pair<shared_ptr<AudioBuffers>, DCPTime>
42 AudioMerger::pull (DCPTime time)
44 /* Number of frames to return */
45 Frame const to_return = time.frames_floor (_frame_rate) - _last_pull.frames_floor (_frame_rate);
46 shared_ptr<AudioBuffers> out (new AudioBuffers (_buffers->channels(), to_return));
48 /* And this is how many we will get from our buffer */
49 Frame const to_return_from_buffers = min (to_return, Frame (_buffers->frames()));
51 /* Copy the data that we have to the back end of the return buffer */
52 out->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
53 /* Silence any gap at the start */
54 out->make_silent (0, to_return - to_return_from_buffers);
56 DCPTime out_time = _last_pull;
59 /* And remove the data we're returning from our buffers */
60 if (_buffers->frames() > to_return_from_buffers) {
61 _buffers->move (to_return_from_buffers, 0, _buffers->frames() - to_return_from_buffers);
63 _buffers->set_frames (_buffers->frames() - to_return_from_buffers);
65 return make_pair (out, out_time);
69 AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
71 DCPOMATIC_ASSERT (time >= _last_pull);
73 Frame const frame = time.frames_floor (_frame_rate);
74 Frame after = max (Frame (_buffers->frames()), frame + audio->frames() - _last_pull.frames_floor (_frame_rate));
75 _buffers->ensure_size (after);
76 _buffers->accumulate_frames (audio.get(), 0, frame - _last_pull.frames_floor (_frame_rate), audio->frames ());
77 _buffers->set_frames (after);