[mythtv] possible libavformat incompatibility with certain MPEG TS files

Rob Jones robj at fastmail.fm
Fri May 26 08:55:41 UTC 2006


I've been attempting to setup a dbox2 with mythtv (0.19 fixes branch).
Streaming of transport streams from the dbox  works ok, but libavformat
has issues reading the tables and assigning the PIDs when attempting to
play back the stream in myth. It doesn't *seem* to be a problem with
anything non-standard in the file, as dvbsnoop, tsreader analyzers have
no problems showing its contents, with a PMT and video/audio PIDs, and
mplayer etc. have no problems playing it back.

Errors from libav look like this:

mpegts_add_stream: at pid 0x18b4 with type 256
mpegts_add_stream: stream #0, has id 0x18b4 and codec DVB_SUBTITLE, type
Subtitle at 0x81502f0
mpegts_add_stream: at pid 0x1804 with type 2
mpegts_add_stream: stream #1, has id 0x1804 and codec MPEG2VIDEO, type
Video at 0x81508c0
mpegts_add_stream: at pid 0x18a4 with type 4
mpegts_add_stream: stream #2, has id 0x18a4 and codec MP3, type Audio at
av_remove_stream 0x18a4
av_remove_stream: no change to cur_st
av_remove_stream: removing... s->nb_streams=3 i=2
av_remove_stream: mpegts_remove_stream
mpegts_remove_stream 0x18a4
closing filter for pid 0x18a4
av_remove_stream: renumbering streams
av_remove_stream 0x1804
av_remove_stream: no change to cur_st
av_remove_stream: removing... s->nb_streams=2 i=1
av_remove_stream: mpegts_remove_stream
mpegts_remove_stream 0x1804
closing filter for pid 0x1804
av_remove_stream: renumbering streams
av_remove_stream 0x18b4
av_remove_stream: no change to cur_st
av_remove_stream: removing... s->nb_streams=1 i=0
av_remove_stream: mpegts_remove_stream

This continues perpetually. It looks as though the stream gets assigned,
but that libavformat thinks the PMT has changed, removes the stream and
goes off to look again. Without a better knowledge of how libavformat
works I can't tell for sure why this going wrong.

I've posted the offending TS at:

Any chance someone could take a look and see if they can figure it out?


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