From 4cb33e432c7070f59c3ee3fbeb0b5c8755bba3bd Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Mon, 22 Oct 2012 11:21:31 +0100
Subject: Partial fix to sync according to pts.

---
 src/lib/ffmpeg_decoder.cc | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'src/lib/ffmpeg_decoder.cc')

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index e52ea735f..d8a541be3 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -66,6 +66,7 @@ FFmpegDecoder::FFmpegDecoder (boost::shared_ptr<const FilmState> s, boost::share
 	, _audio_codec (0)
 	, _subtitle_codec_context (0)
 	, _subtitle_codec (0)
+	, _first_video_pts (-1)
 {
 	setup_general ();
 	setup_video ();
@@ -221,6 +222,8 @@ FFmpegDecoder::do_pass ()
 		_packet.data = 0;
 		_packet.size = 0;
 
+		/* XXX: should we reset _packet.data and size after each *_decode_* call? */
+
 		int frame_finished;
 
 		while (avcodec_decode_video2 (_video_codec_context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
@@ -245,6 +248,9 @@ FFmpegDecoder::do_pass ()
 
 		int frame_finished;
 		if (avcodec_decode_video2 (_video_codec_context, _frame, &frame_finished, &_packet) >= 0 && frame_finished) {
+			if (_first_video_pts == -1) {
+				_first_video_pts = _packet.pts;
+			}
 			process_video (_frame);
 		}
 
@@ -417,3 +423,15 @@ FFmpegDecoder::stream_name (AVStream* s) const
 
 	return n.str ();
 }
+
+int
+FFmpegDecoder::audio_to_discard () const
+{
+	AVStream* v = _format_context->streams[_video_stream];
+	AVStream* a = _format_context->streams[_audio_stream];
+
+	assert (v->time_base.num == a->time_base.num);
+	assert (v->time_base.den == a->time_base.den);
+
+	return rint (av_q2d (v->time_base) * 1000 * (_first_video_pts - _first_audio_pts));
+}
-- 
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