[gst-devel] Adding alpha or transparency to video

[LRN]

Jonathan Wong wrote:
> Hi,
>
> I forgot to mention I need it on Windows (and then Linux later).
>
> I found this: http://pbx.mine.nu/effectv/ (a port of effectv to win32, using DirectShow no less)
>
> I am hoping to programmatically make a video stream semi-transparent (alpha channel).
>   
GStreamer (GstBuffer) supports colorspaces with alpha-channel. Adding
transparency is as simple as converting your video to the right
colorspace (AYUV or RGBA) using ffmpegcolorspace element and then
changing the alpha values to something other than default (this could be
done by your own element, or by existing one, if you manage to find it).
However, not all videosinks and video codecs support such colorspaces,
so that depends on what you are planning to do with the video.