[mythtv-users] dbox2 SPTS incompatibility with mythfrontend

[Rob Jones]

Just a slight update to this; I thought this might be an issue with CA
PIDs being in one of these transport streams. I therefore recorded the
same unencrypted channel from both a DVB-T card directly controlled from
myth and then from the dbox. The file from the DVB-T card works fine,
but no joy with that from the Dbox, so its not this, and the TS files
with the CA descriptors (but already unencrypted video/audio) play ok in
other programs.

Looking at the TS in both dvbsnoop and TSReader gives no clues as to why
this would be. They are both valid transport streams with mpeg2 audio
and video on normal PIDs, and can be decoded just fine with mplayer, vlc
etc. The only thing I can't get to play the TS is myth.

One thing I have noted is that the problem seems to be related to
libavformat/codec.
I get some strange error messages when it tries to play the file:

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
0x8150e90
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 until the backend is shut down. It looks as
though it sees the audio and video in the file, but then chooses to
ignore them and look for them on different PIDs. Any idea what's going
on here?

Rob


On Thu, 25 May 2006 14:53:30 +0100, "Rob Jones" <robj at fastmail.fm> said:
> Hi all,
>  
> I'm trying to get my dbox2 cable receiver to play with mythtv (0.19
> fixes branch). I've got the two talking together, and have been able to
> get mythtv to receive an SPTS stream from the dbox. The problem occurs
> when I try and play back the file. I get an error from mythfrontend that
> it can't find a suitable codec for the file.
>  
> My gut instinct was that the PMT was missing from the TS and that myth
> didn't know what to treat the TS as, but I've
> successfully been able to get VLC to play the stream without any
> problems. As far as I can tell, its just a plain SPTS stream with one
> MPEG2 video stream and a couple of audios and a subtitle track, but
> mythfrontend refuses to touch it.
>
> Could anyone suggest a way to diagnose what exactly myth doesn't like
> about it?
>  
> Also, on a side note, this dbox is used as a set-top box rather than
> just as a myth input device. Therefore it would be useful to lock the
> remote when streaming to myth is taking place (this can be done, I
> believe the sage-tv mythtv plugin which uses ggrab does this), and to
> prevent epg scanning altogether as the epg data is retrieved through
> xmltv. Any way I can pass this on to the maintainer of the dbox/mythtv
> code? If not a spot of patching may be in order!
>  
> Cheers,
>  
> Rob
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