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/*
Copyright (C) 2013-2014 Carl Hetherington <cth@carlh.net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "audio_buffers.h"
#include "audio_merger.h"
using std::min;
using std::max;
using boost::shared_ptr;
AudioMerger::AudioMerger (int channels, int frame_rate)
: _buffers (new AudioBuffers (channels, 0))
, _frame_rate (frame_rate)
, _last_pull (0)
{
}
TimedAudioBuffers
AudioMerger::pull (DCPTime time)
{
assert (time >= _last_pull);
TimedAudioBuffers out;
int64_t const to_return = DCPTime (time - _last_pull).frames (_frame_rate);
out.audio.reset (new AudioBuffers (_buffers->channels(), to_return));
/* And this is how many we will get from our buffer */
int64_t const to_return_from_buffers = min (to_return, int64_t (_buffers->frames ()));
/* Copy the data that we have to the back end of the return buffer */
out.audio->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
/* Silence any gap at the start */
out.audio->make_silent (0, to_return - to_return_from_buffers);
out.time = _last_pull;
_last_pull = time;
/* And remove the data we're returning from our buffers */
if (_buffers->frames() > to_return_from_buffers) {
_buffers->move (to_return_from_buffers, 0, _buffers->frames() - to_return_from_buffers);
}
_buffers->set_frames (_buffers->frames() - to_return_from_buffers);
return out;
}
void
AudioMerger::push (shared_ptr<const AudioBuffers> audio, DCPTime time)
{
assert (time >= _last_pull);
int64_t frame = time.frames (_frame_rate);
int64_t after = max (int64_t (_buffers->frames()), frame + audio->frames() - _last_pull.frames (_frame_rate));
_buffers->ensure_size (after);
_buffers->accumulate_frames (audio.get(), 0, frame - _last_pull.frames (_frame_rate), audio->frames ());
_buffers->set_frames (after);
}
TimedAudioBuffers
AudioMerger::flush ()
{
if (_buffers->frames() == 0) {
return TimedAudioBuffers ();
}
return TimedAudioBuffers (_buffers, _last_pull);
}
void
AudioMerger::clear (DCPTime t)
{
_last_pull = t;
_buffers.reset (new AudioBuffers (_buffers->channels(), 0));
}
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