[gst-devel] video overlay plugin

Gustavo J A M Carneiro gjc at inescporto.pt
Mon Apr 21 13:45:05 CEST 2003

  Thanks for your comments!  I agree with you, btw, I just hadn't
thought of that. :P

A Seg, 2003-04-21 às 15:59, Ronald Bultje escreveu:
> Hey Gustavo,
> On Mon, 2003-04-21 at 16:13, Gustavo J A M Carneiro wrote:
> >   My idea is for this to be used to display subtitles in gst-player. 
> > Any volunteers for that?  Should be fairly simple to do the rest.  We
> > only have to insert textoverlay in the pipeline, read a subtitles file,
> > and then change the 'text' attribute of the textoverlay from time to
> > time.
> The 'pipeline' idea is that this happens within the gstreamer pipeline
> as well. mpegdemux, for example, can separate the subtitle streams.
> There's another plugin (mpeg2subt) that decodes it into timestamped text
> buffers, and the text plugin should read this and blit it onto the video
> buffer. It can use the timestamp on the buffer for timing etc.
> Properties and so on is nice, but it's basically a quick hack that
> requires a lot of information from the application, while the idea of
> gst is to keep apps simple and have plugins do all the work... The
> pipeline then looks like:
> filesrc->mpegdemux.video_00->   mpeg2dec-> textoverlay->xvideosink
>                 \\\                                     ///
>                  \\\  .subtitle_00->mpeg2subt->///
>                   \\\
>                    \\\.audio_00->mad->osssink
> See? In case of a separate subtitle file, you would open that using a
> separate filesrc:
> filesrc->subtitleparse->                     \\\
>                                                       \\\
> filesrc->mpegdemux.video_00->mpeg2dec-> textoverlay->xvideosink
>                   \\\
>                    \\\.audio_00->mad->osssink
> This is the design proposed some time ago. You still need the
> textoverlay plugin you've designed, don't worry about that, but you
> transfer the text over a GstPad (timestamped) rather than over a
> property.
> (Oh, we mostly use bugzilla (http://bugzilla.gnome.org/) for these kind
> of things. If you prefer that, please upload the plugin there, it's easy
> to lose track of stuff on the mailinglist, while that cannot happen
> easily on bugzilla).
> Anyway, thanks for the work!
> Ronald
Gustavo J. A. M. Carneiro
<gjc at inescporto.pt> <gustavo at users.sourceforge.net>

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