Support for keyframe-only trickmode

[Tim-Philipp Müller]

On Wed, 2012-11-21 at 13:56 -0800, gimmeamilk wrote:

> My application needs to support keyframe-only high-speed trickmode, both
> forward and reverse. So to get reasonable performance I need to ensure only
> keyframes are pushed from as far upstream as possible.
> 
> I was thinking of making a "KeyframeFilter" plugin that sits just downstream
> from the demuxer and, when enabled, only passes down the keyframes. (it
> would check the GST_BUFFER_FLAG_DELTA_UNIT on the incoming buffers to decide
> which were keyframes).
> 
> Is this a reasonable solution? I couldn't find any support for this within
> the demuxers themselves (specifically qtdemux), so I suppose this is the
> next best thing in terms of efficiency. Or has a better way already been
> implemented?

There's a SKIP seek flag that's supposed to be for this. You could just
implement that in the demuxer(s) in question, shouldn't be too hard,
hopefully. (1.0 please).

You can also drop select buffers using a pad probe, fwiw.

Cheers 
 -Tim