DVB sub-pictures wrongly displayed

[Mart Raudsepp]

Hello,

On N, 2011-12-08 at 05:49 -0800, TruBzzz wrote:
> Hi GStreamer team,
> 
> I experienced issues while decoding DVB subtitles contained in mpegTS files: 
> Here is a sample of the rendering
> http://gstreamer-devel.966125.n4.nabble.com/file/n4172790/dvbsub1.png 
> I used the 'dvbsuboverlay' element in following pipeline like
> /// gst-launch -v filesrc location=video.mpg  ! mpegtsdemux name=d ! 
> //               queue ! mp3parse ! mad ! audioconvert ! autoaudiosink d. ! 
> //               queue !  ffdec_h264 ! ffmpegcolorspace ! r. d. ! 
> //               queue ! "subpicture/x-dvb" ! dvbsuboverlay name=r !
> ffmpegcolorspace ! autovideosink
> /
> 
> It may be related or not, but I got this logs from the parser:
> */WARNING **: Parsing 2bit color DVB sub-picture. This is not tested at all.
> If you see this message, please provide the developers with sample media
> with these subtitles, if possible./*
> If you are interested, I'll be able to provide a sample media with these
> subtitles.

Yes, that must be it. I never found any 2bit or 8bit samples to actually
test the code with. All channels in Estonia and Finland used 4bit; I
believe also some samples from UK/Spain were 4bit.
So some sample media would be most appreciated. Not sure how to get it,
but I believe if it can be public, there are some place on freedesktop
server we can store it once someone with access has it. Maybe they are
small enough as a bugzilla attachment, especially if just the subtitle
elementary stream?

> Furthermore, I notice that ffmpeg provide also a plugin 'ffdec_dvbsub' but I
> didn't succeed to decode the same file with this decoder.

The dvb-sub.c code from dvbsuboverlay plugin originates from libdvbsub I
wrote for a DVB box back in the day, this code is at
https://github.com/leio/libdvbsub