From 60fcc19b9068614f25cf64dff5e4aa0e8dbff6a5 Mon Sep 17 00:00:00 2001 From: Graham Booker <gbooker@tamu.edu> Date: Fri, 11 Apr 2014 23:26:46 -0500 Subject: avformat/mpegtsenc: Changed Video PES packet length to 0. The rational for this is another issue that plex has exposed. When it is conducting a transcode of video to HLS for streaming, my father noticed artifacts when played on his GoogleTV (NSZ-GT1). He sent me a test file and I reproduced it on my device of the same model. It is important to note that the artifacts were not present when streaming to VLC or QuickTime Player. I copied the command-line that plex used, and conducted all of the following tests using FFmpeg git. Transcode to HLS: artifacts on playback Transcode to TS: playback is fine Cat HLS segments into a single TS: playback is fine Segment single TS file to segments: artifacts on playback Segment single TS file to segments using Apple's HLS segmenter: playback is fine At this point I carefully examined the differences between Apple's HLS segmenter output and FFmpeg's. Among the considerable differences, I noticed that the video PES packets always had a 0 length. So I continued: Transcode to HLS using FFmpeg with 0 length PES packets: playback is fine. Segment single TS to segments with 0 length PES packets: playback is fine. All failures mentioned are only on the GTV since it is the only player on which I could reproduce artifacts. I only tested the GTV, VLC, and QuickTime Player though, so my test case is limited. I do not know if other players exhibit this issue. Since it was useful last time, I have uploaded the test file as hls_pes_packet_length.m4v along with its associated txt file which contains the transcode command-line that was used. Reviewed-by: Kieran Kunhya <kierank@obe.tv> Signed-off-by: Michael Niedermayer <michaelni@gmx.at> --- libavformat/mpegtsenc.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'libavformat') diff --git a/libavformat/mpegtsenc.c b/libavformat/mpegtsenc.c index 8d80e072a0..9cc17ccb1d 100644 --- a/libavformat/mpegtsenc.c +++ b/libavformat/mpegtsenc.c @@ -1066,6 +1066,9 @@ static void mpegts_write_pes(AVFormatContext *s, AVStream *st, } if (len > 0xffff) len = 0; + if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) { + len = 0; + } *q++ = len >> 8; *q++ = len; val = 0x80; -- cgit v1.2.3