From 48cd8b6a44ab689ad2eb8e6d86e086def995d9ba Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Sun, 3 Sep 2017 01:41:50 +0100
Subject: [PATCH] Cope with e.g. truehd audio streams having not every audio
 frame arriving with a pts.

---
 src/lib/ffmpeg_decoder.cc | 37 ++++++++++++++++++++++++++++++-------
 src/lib/ffmpeg_decoder.h  |  2 ++
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index af309cdbe..3cbd0304e 100644
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -100,6 +100,8 @@ FFmpegDecoder::FFmpegDecoder (shared_ptr<const FFmpegContent> c, shared_ptr<Log>
 	if (c->subtitle) {
 		subtitle.reset (new SubtitleDecoder (this, c->subtitle, log));
 	}
+
+	_next_time.resize (_format_context->nb_streams);
 }
 
 void
@@ -392,11 +394,12 @@ FFmpegDecoder::decode_audio_packet ()
 	*/
 
 	AVPacket copy_packet = _packet;
+	int const stream_index = copy_packet.stream_index;
 
 	/* XXX: inefficient */
 	vector<shared_ptr<FFmpegAudioStream> > streams = ffmpeg_content()->ffmpeg_audio_streams ();
 	vector<shared_ptr<FFmpegAudioStream> >::const_iterator stream = streams.begin ();
-	while (stream != streams.end () && !(*stream)->uses_index (_format_context, copy_packet.stream_index)) {
+	while (stream != streams.end () && !(*stream)->uses_index (_format_context, stream_index)) {
 		++stream;
 	}
 
@@ -426,13 +429,24 @@ FFmpegDecoder::decode_audio_packet ()
 		}
 
 		if (frame_finished) {
-			ContentTime ct = ContentTime::from_seconds (
-				av_frame_get_best_effort_timestamp (_frame) *
-				av_q2d ((*stream)->stream (_format_context)->time_base))
-				+ _pts_offset;
-
 			shared_ptr<AudioBuffers> data = deinterleave_audio (*stream);
 
+			ContentTime ct;
+			if (_frame->pts == AV_NOPTS_VALUE && _next_time[stream_index]) {
+				/* In some streams we see not every frame coming through with a timestamp; for those
+				   that have AV_NOPTS_VALUE we need to work out the timestamp ourselves.  This is
+				   particularly noticeable with TrueHD streams (see #1111).
+				*/
+				ct = *_next_time[stream_index];
+			} else {
+				ct = ContentTime::from_seconds (
+					av_frame_get_best_effort_timestamp (_frame) *
+					av_q2d ((*stream)->stream (_format_context)->time_base))
+					+ _pts_offset;
+			}
+
+			_next_time[stream_index] = ct + ContentTime::from_frames(data->frames(), (*stream)->frame_rate());
+
 			if (ct < ContentTime ()) {
 				/* Discard audio data that comes before time 0 */
 				Frame const remove = min (int64_t (data->frames()), (-ct).frames_ceil(double((*stream)->frame_rate ())));
@@ -442,7 +456,16 @@ FFmpegDecoder::decode_audio_packet ()
 			}
 
 			if (ct < ContentTime()) {
-				LOG_WARNING ("Crazy timestamp %1", to_string (ct));
+				LOG_WARNING (
+					"Crazy timestamp %1 for %2 samples in stream %3 packet pts %4 (ts=%5 tb=%6, off=%7)",
+					to_string(ct),
+					data->frames(),
+					copy_packet.stream_index,
+					copy_packet.pts,
+					av_frame_get_best_effort_timestamp(_frame),
+					av_q2d((*stream)->stream(_format_context)->time_base),
+					to_string(_pts_offset)
+					);
 			}
 
 			/* Give this data provided there is some, and its time is sane */
diff --git a/src/lib/ffmpeg_decoder.h b/src/lib/ffmpeg_decoder.h
index 3ea5f5809..993d1dd0e 100644
--- a/src/lib/ffmpeg_decoder.h
+++ b/src/lib/ffmpeg_decoder.h
@@ -78,4 +78,6 @@ private:
 	bool _have_current_subtitle;
 
 	boost::shared_ptr<Image> _black_image;
+
+	std::vector<boost::optional<ContentTime> > _next_time;
 };
-- 
2.30.2