[gst-devel] dvdsrc status update, sundry questions

Mark Nauwelaerts manauw at skynet.be
Wed Dec 13 00:03:27 CET 2006

Wim Taymans wrote:
> On Fri, 2006-12-08 at 17:42 -0700, Jason Gerard DeRose wrote:
>> Hello everyone,
> Hi,
>> 3) Is 'videomixer' suitable for overlaying the decoded subtitles? Once I
>> have dvdsubdec working again, is 'videomixer' what should be used?
> For DVD I would create a subtitle mixer that takes video on one pad and
> the encoded subpicture on another pad. The element is purely chain
> based, for each video picture received it blends (while unpacking) the
> current subtitle on top of it (with matching timestamps, of course).
> When you connect the demuxers subtitle pad directly to the subtitle
> decoder/mixer and the raw video path of the video decoder to the mixer
> video path, you will get the subpicture before the video frames it
> applies to. You can insert an order-preserving queue (like decodebin2
> does) to make sure none of the video/subtitle streams run ahead of
> eachother (multiqueue).

Small question on this.
It seems that this (new) mixer element (with the techniques as given above) has
much to do with "programming around" the limitations of collectpads (in dealing
with sparse streams like subtitles) that is used in e.g. videomixer (?)

Could it be helpful / somehow possible to (re-)use the techniques given above in
a sort of upgraded collectpads that could then also be of use to muxers that
might be interested/capable in muxing subtitles, e.g. a matroskamux ?


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