[gst-devel] Subtitle support in 0.10

[Stefan Kost]

hi michal,

Michal Benes wrote:
> Hi all,
>
> 	I want to add support for subtitles to matroska muxer. The problem is
> that filler events have been (temporarily) removed and if I understand
> it well there not yet consensus how to handle sparse streams (especially
> in collectpads).
>
> 	May be, a good solution would be to introduce empty "filler buffers"
> instead of events. As a temporary hack I plan to push an empty buffer to
> the pipeline every second (and drop empty buffers in matroska muxer).
>
> 	What are your thoughts on this?
>
> 		Michal
>   
I don't know the internals of the sub-titles, heres a thought anyway:

Isn't a subtitle just a block of text that is valid for some time? If so
can't we use the gst-controller for it.
Then the sub-title-renderer would need a text propertiy, that gets the
GST_PARAM_CONTROLLABLE flag.
Whever the parser comes across new subtitles, it would add them to the
sub-title-renderers controller queue:
gst_controller_set(ctrl, "subtitle",timestamp,str_value);

The subtitle-renderer in turn would call
gst_object_sync_values(self, timestamp);
for every frame to get the schedules subtitle changes.

Tell me if you thing that this should work, as I need to add the string
gvalue type to the supported types in the controller (it an easy change).

Stefan