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/*
Copyright (C) 2013-2021 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.
*/
/** @file src/audio_merger.cc
* @brief AudioMerger class.
*/
#include "audio_merger.h"
#include "dcpomatic_time.h"
#include <iostream>
using std::cout;
using std::list;
using std::make_pair;
using std::make_shared;
using std::max;
using std::min;
using std::pair;
using std::shared_ptr;
using boost::optional;
using namespace dcpomatic;
AudioMerger::AudioMerger (int frame_rate)
: _frame_rate (frame_rate)
{
}
Frame
AudioMerger::frames (DCPTime t) const
{
return t.frames_floor (_frame_rate);
}
/** Pull audio up to a given time; after this call, no more data can be pushed
* before the specified time.
* @param time Time to pull up to.
* @return Blocks of merged audio up to `time'.
*/
list<pair<shared_ptr<AudioBuffers>, DCPTime>>
AudioMerger::pull (DCPTime time)
{
list<pair<shared_ptr<AudioBuffers>, DCPTime>> out;
list<Buffer> new_buffers;
_buffers.sort ([](Buffer const& a, Buffer const& b) {
return a.time < b.time;
});
for (auto i: _buffers) {
if (i.period().to <= time) {
/* Completely within the pull period */
DCPOMATIC_ASSERT (i.audio->frames() > 0);
out.push_back (make_pair (i.audio, i.time));
} else if (i.time < time) {
/* Overlaps the end of the pull period */
int32_t const overlap = frames(DCPTime(time - i.time));
/* Though time > i.time, overlap could be 0 if the difference in time is less than one frame */
if (overlap > 0) {
auto audio = make_shared<AudioBuffers>(i.audio, overlap, 0);
out.push_back (make_pair(audio, i.time));
i.audio->trim_start (overlap);
i.time += DCPTime::from_frames(overlap, _frame_rate);
DCPOMATIC_ASSERT (i.audio->frames() > 0);
new_buffers.push_back (i);
}
} else {
/* Not involved */
DCPOMATIC_ASSERT (i.audio->frames() > 0);
new_buffers.push_back (i);
}
}
_buffers = new_buffers;
for (auto const& i: out) {
DCPOMATIC_ASSERT (i.first->frames() > 0);
}
return out;
}
/** Push some data into the merger at a given time */
void
AudioMerger::push (std::shared_ptr<const AudioBuffers> audio, DCPTime time)
{
DCPOMATIC_ASSERT (audio->frames() > 0);
DCPTimePeriod period (time, time + DCPTime::from_frames (audio->frames(), _frame_rate));
/* Mix any overlapping parts of this new block with existing ones */
for (auto i: _buffers) {
auto overlap = i.period().overlap(period);
if (overlap) {
int32_t const offset = frames(DCPTime(overlap->from - i.time));
int32_t const frames_to_mix = frames(overlap->duration());
if (i.time < time) {
i.audio->accumulate_frames(audio.get(), frames_to_mix, 0, offset);
} else {
i.audio->accumulate_frames(audio.get(), frames_to_mix, offset, 0);
}
}
}
list<DCPTimePeriod> periods;
for (auto i: _buffers) {
periods.push_back (i.period());
}
/* Add the non-overlapping parts */
for (auto i: subtract(period, periods)) {
auto before = _buffers.end();
auto after = _buffers.end();
for (auto j = _buffers.begin(); j != _buffers.end(); ++j) {
if (j->period().to == i.from) {
before = j;
}
if (j->period().from == i.to) {
after = j;
}
}
/* Get the part of audio that we want to use */
auto part = make_shared<AudioBuffers>(audio, frames(i.to) - frames(i.from), frames(DCPTime(i.from - time)));
if (before == _buffers.end() && after == _buffers.end()) {
if (part->frames() > 0) {
/* New buffer */
_buffers.push_back (Buffer (part, time, _frame_rate));
}
} else if (before != _buffers.end() && after == _buffers.end()) {
/* We have an existing buffer before this one; append new data to it */
before->audio->append (part);
} else if (before ==_buffers.end() && after != _buffers.end()) {
/* We have an existing buffer after this one; append it to the new data and replace */
part->append (after->audio);
after->audio = part;
after->time = time;
} else {
/* We have existing buffers both before and after; coalesce them all */
before->audio->append (part);
before->audio->append (after->audio);
_buffers.erase (after);
}
}
}
void
AudioMerger::clear ()
{
_buffers.clear ();
}
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