2 Copyright (C) 2013 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_buffers.h"
23 template <class T, class F>
27 AudioMerger (int channels, boost::function<F (T)> t_to_f, boost::function<T (F)> f_to_t)
28 : _buffers (new AudioBuffers (channels, 0))
35 push (boost::shared_ptr<const AudioBuffers> audio, T time)
37 assert (time >= _next_out);
39 TimedAudioBuffers<T> out;
41 if (time > _next_out) {
42 /* We can return some audio from our buffer; this is how many frames
43 we are going to return.
45 F const to_return = _t_to_f (time - _next_out);
46 out.audio.reset (new AudioBuffers (_buffers->channels(), to_return));
47 /* And this is how many we will get from our buffer */
48 F const to_return_from_buffers = min (to_return, _buffers->frames ());
50 /* Copy the data that we have to the back end of the return buffer */
51 out.audio->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
52 /* Silence any gap at the start */
53 out.audio->make_silent (0, to_return - to_return_from_buffers);
56 _next_out += _f_to_t (to_return);
58 /* And remove the data we're returning from our buffers */
59 if (_buffers->frames() > to_return_from_buffers) {
60 _buffers->move (to_return_from_buffers, 0, _buffers->frames() - to_return_from_buffers);
62 _buffers->set_frames (_buffers->frames() - to_return_from_buffers);
65 /* Now accumulate the new audio into our buffers */
66 F frame = _t_to_f (time);
67 F after = max (_buffers->frames(), frame + audio->frames() - _t_to_f (_next_out));
68 _buffers->ensure_size (after);
69 _buffers->accumulate_frames (audio.get(), 0, frame - _t_to_f (_next_out), audio->frames ());
70 _buffers->set_frames (after);
96 if (_buffers->frames() == 0) {
97 return TimedAudioBuffers<T> ();
100 return TimedAudioBuffers<T> (_buffers, _next_out);
104 boost::shared_ptr<AudioBuffers> _buffers;
106 boost::function<F (T)> _t_to_f;
107 boost::function<T (F)> _f_to_t;