1 files changed, 224 insertions, 0 deletions
diff --git a/src/lib/matcher.cc b/src/lib/matcher.cc
new file mode 100644
index 000000000..4acb82afa
--- /dev/null
+++ b/src/lib/matcher.cc
@@ -0,0 +1,224 @@
+/*
+    Copyright (C) 2012 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 "matcher.h"
+#include "image.h"
+#include "log.h"
+
+#include "i18n.h"
+
+using std::min;
+using std::cout;
+using std::list;
+using boost::shared_ptr;
+
+Matcher::Matcher (shared_ptr<Log> log, int sample_rate, float frames_per_second)
+	: Processor (log)
+	, _sample_rate (sample_rate)
+	, _frames_per_second (frames_per_second)
+	, _video_frames (0)
+	, _audio_frames (0)
+	, _had_first_video (false)
+	, _had_first_audio (false)
+{
+
+}
+
+void
+Matcher::process_video (boost::shared_ptr<const Image> image, bool same, boost::shared_ptr<Subtitle> sub, double t)
+{
+	_pixel_format = image->pixel_format ();
+	_size = image->size ();
+
+	_log->log(String::compose("Matcher video @ %1 [audio=%2, video=%3, pending_audio=%4]", t, _audio_frames, _video_frames, _pending_audio.size()));
+
+	if (!_first_input || t < _first_input.get()) {
+		_first_input = t;
+	}
+
+	bool const this_is_first_video = !_had_first_video;
+	_had_first_video = true;
+
+	if (!_had_first_audio) {
+		/* No audio yet; we must postpone these data until we have some */
+		_pending_video.push_back (VideoRecord (image, same, sub, t));
+	} else if (this_is_first_video && _had_first_audio) {
+		/* First video since we got audio */
+		_pending_video.push_back (VideoRecord (image, same, sub, t));
+		fix_start ();
+	} else {
+		/* Normal running */
+
+		/* Difference between where this video is and where it should be */
+		double const delta = t - _first_input.get() - _video_frames / _frames_per_second;
+		double const one_frame = 1 / _frames_per_second;
+		
+		if (delta > one_frame) {
+			/* Insert frames to make up the difference */
+			int const extra = rint (delta / one_frame);
+			for (int i = 0; i < extra; ++i) {
+				repeat_last_video ();
+				_log->log (String::compose ("Extra video frame inserted at %1s", _video_frames / _frames_per_second));
+			}
+		}
+		
+		if (delta > -one_frame) {
+			Video (image, same, sub);
+			++_video_frames;
+		} else {
+			/* We are omitting a frame to keep things right */
+			_log->log (String::compose ("Frame removed at %1s; delta %2; first input was at %3", t, delta, _first_input.get()));
+		}
+		
+		_last_image = image;
+		_last_subtitle = sub;
+	}
+}
+
+void
+Matcher::process_audio (boost::shared_ptr<const AudioBuffers> b, double t)
+{
+	_channels = b->channels ();
+
+	_log->log (String::compose (
+			   "Matcher audio (%1 frames) @ %2 [video=%3, audio=%4, pending_video=%5, pending_audio=%6]",
+			   b->frames(), t, _video_frames, _audio_frames, _pending_video.size(), _pending_audio.size()
+			   )
+		);
+
+	if (!_first_input || t < _first_input.get()) {
+		_first_input = t;
+	}
+
+	bool const this_is_first_audio = !_had_first_audio;
+	_had_first_audio = true;
+	
+	if (!_had_first_video) {
+		/* No video yet; we must postpone these data until we have some */
+		_pending_audio.push_back (AudioRecord (b, t));
+	} else if (this_is_first_audio && _had_first_video) {
+		/* First audio since we got video */
+		_pending_audio.push_back (AudioRecord (b, t));
+		fix_start ();
+	} else {
+		/* Normal running.  We assume audio time stamps are consecutive, so there's no equivalent of
+		   the checking / insertion of repeat frames that there is for video.
+		*/
+		Audio (b);
+		_audio_frames += b->frames ();
+	}
+}
+
+void
+Matcher::process_end ()
+{
+	if (_audio_frames == 0 || !_pixel_format || !_size || !_channels) {
+		/* We won't do anything */
+		return;
+	}
+
+	_log->log (String::compose ("Matcher has seen %1 video frames (which equals %2 audio frames) and %3 audio frames",
+				    _video_frames, video_frames_to_audio_frames (_video_frames, _sample_rate, _frames_per_second), _audio_frames));
+	
+	match ((double (_audio_frames) / _sample_rate) - (double (_video_frames) / _frames_per_second));
+}
+
+void
+Matcher::fix_start ()
+{
+	assert (!_pending_video.empty ());
+	assert (!_pending_audio.empty ());
+	
+	_log->log (String::compose ("Fixing start; video at %1, audio at %2", _pending_video.front().time, _pending_audio.front().time));
+
+	match (_pending_video.front().time - _pending_audio.front().time);
+
+	for (list<VideoRecord>::iterator i = _pending_video.begin(); i != _pending_video.end(); ++i) {
+		process_video (i->image, i->same, i->subtitle, i->time);
+	}
+
+	_pending_video.clear ();
+
+	for (list<AudioRecord>::iterator i = _pending_audio.begin(); i != _pending_audio.end(); ++i) {
+		process_audio (i->audio, i->time);
+	}
+	
+	_pending_audio.clear ();
+}
+
+void
+Matcher::match (double extra_video_needed)
+{
+	_log->log (String::compose ("Match %1", extra_video_needed));
+	
+	if (extra_video_needed > 0) {
+
+		/* Emit black video frames */
+		
+		int const black_video_frames = ceil (extra_video_needed * _frames_per_second);
+
+		_log->log (String::compose (N_("Emitting %1 frames of black video"), black_video_frames));
+
+		shared_ptr<Image> black (new SimpleImage (_pixel_format.get(), _size.get(), true));
+		black->make_black ();
+		for (int i = 0; i < black_video_frames; ++i) {
+			Video (black, i != 0, shared_ptr<Subtitle>());
+			++_video_frames;
+		}
+
+		extra_video_needed -= black_video_frames / _frames_per_second;
+	}
+
+	if (extra_video_needed < 0) {
+		
+		/* Emit silence */
+		
+		int64_t to_do = -extra_video_needed * _sample_rate;
+		_log->log (String::compose (N_("Emitting %1 frames of silence"), to_do));
+
+		/* Do things in half second blocks as I think there may be limits
+		   to what FFmpeg (and in particular the resampler) can cope with.
+		*/
+		int64_t const block = _sample_rate / 2;
+		shared_ptr<AudioBuffers> b (new AudioBuffers (_channels.get(), block));
+		b->make_silent ();
+		
+		while (to_do > 0) {
+			int64_t const this_time = min (to_do, block);
+			b->set_frames (this_time);
+			Audio (b);
+			_audio_frames += b->frames ();
+			to_do -= this_time;
+		}
+	}
+}
+
+void
+Matcher::repeat_last_video ()
+{
+	if (!_last_image) {
+		shared_ptr<Image> im (new SimpleImage (_pixel_format.get(), _size.get(), true));
+		im->make_black ();
+		_last_image = im;
+	}
+
+	Video (_last_image, true, _last_subtitle);
+	++_video_frames;
+}
+