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/*
Copyright (C) 2013-2016 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_merger.h"
#include "dcpomatic_time.h"
#include <iostream>
using std::pair;
using std::min;
using std::max;
using std::make_pair;
using boost::shared_ptr;
AudioMerger::AudioMerger (int channels, int frame_rate)
: _buffers (new AudioBuffers (channels, 0))
, _last_pull (0)
, _frame_rate (frame_rate)
{
}
/** Pull audio up to a given time; after this call, no more data can be pushed
* before the specified time.
*/
pair<shared_ptr<AudioBuffers>, DCPTime>
AudioMerger::pull (DCPTime time)
{
/* Number of frames to return */
Frame const to_return = time.frames_floor (_frame_rate) - _last_pull.frames_floor (_frame_rate);
shared_ptr<AudioBuffers> out (new AudioBuffers (_buffers->channels(), to_return));
/* And this is how many we will get from our buffer */
Frame const to_return_from_buffers = min (to_return, Frame (_buffers->frames()));
/* Copy the data that we have to the back end of the return buffer */
out->copy_from (_buffers.get(), to_return_from_buffers, 0, to_return - to_return_from_buffers);
/* Silence any gap at the start */
out->make_silent (0, to_return - to_return_from_buffers);
DCPTime 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 make_pair (out, out_time);
}
void
AudioMerger::push (boost::shared_ptr<const AudioBuffers> audio, DCPTime time)
{
DCPOMATIC_ASSERT (time >= _last_pull);
Frame const frame = time.frames_floor (_frame_rate);
Frame after = max (Frame (_buffers->frames()), frame + audio->frames() - _last_pull.frames_floor (_frame_rate));
_buffers->ensure_size (after);
_buffers->accumulate_frames (audio.get(), 0, frame - _last_pull.frames_floor (_frame_rate), audio->frames ());
_buffers->set_frames (after);
}
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