[FFmpeg-trac] #7611(undetermined:new): Problems on recording of teletext subtitles of an iptv stream after a large amount of time.

FFmpeg trac at avcodec.org
Wed Dec 12 15:41:38 EET 2018

#7611: Problems on recording of teletext subtitles of an iptv stream after a large
amount of time.
             Reporter:  agrafiods    |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
 We have a system using ffmpeg to record and segment incoming iptv streams
 with teletext subtitles and then feed the generated files for further
 processing. After about 25-27 hours of continuous recording without any
 issues (both logwise and in processing) ffmpeg starts generating
 systematic DTS discontinuities on the subtitle stream (on every packet
 actually) and the subtitles of the generated files cannot be correctly
 parsed on the later steps, either they do not appear at all, or a few
 lines appear collapsed on the beginning of the clip. Simply stopping and
 starting the ffmpeg will fix the issue for the previously mentioned
 period. Source streams are local tvheadend streams (with pass profile).
 This happens on every source stream and only appears to be affected by the
 time the process is continuously running (that is, sources started at
 different times will each start failing after the above time has passed
 since its beginning).

 command is: ffmpeg -fix_sub_duration -i <ipstream> -map 0 - c:v copy -c:a
 copy -c:s copy -f segment -segment_time 180 -reset_timestamps 1 -strftime
 1 someid_%Y-%m-%d-%H-%M-%S.ts

 Tested this with versions 3.3.8 (via deb.multimedia), several static
 builds of November 2018 and a compilation of ffmpeg on 2018-12-05 as per
 Compilation configuration was "configuration:
 --prefix=/home/user/ffmpeg_compile_2018_12_05 --pkg-config-flags=--static
 --extra-cflags=-I/home/user/ffmpeg_compile_2018_12_05/include --extra-
 ldflags=-L/home/user/ffmpeg_compile_2018_12_05/lib --extra-libs='-lpthread
 -lm' --bindir=/home/user/ffmpeg_compile_2018_12_05/bin --enable-gpl
 --enable-openssl --enable-version3 --enable-static --enable-fontconfig
 --enable-frei0r --enable-gray --enable-libfribidi --enable-libass
 --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-
 libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
 --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libopus
 --enable-libvorbis --enable-libtheora --enable-libvidstab --enable-libvpx
 --enable-libvo-amrwbenc --enable-libwebp --enable-libxml2 --enable-libx264
 --enable-libx265 --enable-libxvid --enable-libzvbi --enable-nonfree"

Ticket URL: <https://trac.ffmpeg.org/ticket/7611>
FFmpeg <https://ffmpeg.org>
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