On 06/12/2016 08:23 AM, Michael Niedermayer wrote: > On Sat, Jun 11, 2016 at 06:55:32PM -0400, DeHackEd wrote: >> Presently the mpegts demuxer passes the timestamps from received packets >> directly to the output AVPackets. 2^33 / 90000 >> seconds is about 26.5 hours at which point applications start having a fit, >> and that's assuming timestamps begin at time 0. >> >> So here's a first revision of a patch to fix that issue. >> >> Improvements possible: >> * In its current form intended for continuous sources like over-the-air >> receivers and multicast sources. When used on >> files there will be problems with seeking. >> * Constants such as 2^33 could be turned into macros for readability > >> mpegts.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++-------- >> 1 file changed, 48 insertions(+), 8 deletions(-) >> b95c5f58685106dab1f434a3bb465ad5a0ba1636 new-pts-dts.patch >> From d06a3bd39fc4f01b9ce6132d80634dd31be7b1aa Mon Sep 17 00:00:00 2001 >> From: DHE <g...@dehacked.net> >> Date: Mon, 30 May 2016 18:31:43 -0400 >> Subject: [PATCH] libavformat/mpegts: Prevent wrapping of PTS & DTS > > this could cause issues with seeking (as the same packet could > result in different timestamps depending on luck) as well as subtitles > (which could get misidentified as wraps)
Yes, I found that in testing. Unfortunately I don't know enough about ffmpeg to fix that myself at this time. It's a big reason I'm posting this patch as [RFC]. > also mpeg-ps has the same kind of timestamps, > If there is an issue that would affect it too, a fix should be in > common code > iam not sure what issue there is though, it seems you expect something > from the demuxer that its not supposed to do. I did it this way because 1) it's the issue I personally ran into, and 2) I was talking about it in #ffmpeg-devel and was told "mpegts demuxer should handle the wrapping in itself and just output timestamps that are rising"[1], so I did. > mpeg-ps/ts have 33bit timestamps and they wrap, anything done to > the wraping belongs to the user applications or common code in > libavformat. > > If you want to remove timestamp discontinuities in libavformat properly > or just wraps, thats more complex and will require keeping track of > where the discontinuities are so that seeking around in the virtual > continuous timeline works and is fully consistant > -- [1] http://ffmpeg.gusari.org/irclogs/2016/05/30/ffmpeg-devel.log.20160530 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
