[MPlayer-dev-eng] dr2 implementation thoughts

[D Richard Felker III]

On Wed, Jul 17, 2002 at 01:07:29AM +0200, Arpi wrote:
> Hi,
> 
> > counteracting much of the speed gain. Instead, I'm thinking, why not
> > pass the changed macroblock mask along with the draw_slice call, for
> 
> hmm, good idea. at least it makes things simpler than passing the whole
> array & stride. also, it could benefit from draw_slice callback and the
> mb_skip at the same time. only disadvantage is that it's limited to yv12
> then. (draw_slice is yv12 only)

Oh? What's used for other colorspaces then? I'm so used to mga_vid and
lavc/libmpeg2 that I almost forget about other ones existing. :)

> > 3) Potential applications for filters. Some video filters, especially
> >    postprocessing, may want to modify not just the macroblocks changed
> >    by the codec in the present frame, but also all adjacent
> >    macroblocks. To do this, the filter could just make its
> >    modifications and then add the macroblocks it changed to the list
> >    before passing it on to the next filter/vo in the chain.
> good idea, anyway too complex to implement :(

Yeah, but a design like this would leave that possibility open for the
future, in case someone feels ambitious. Also, there's the possibility
that some filters could be added that do nothing *but* change the mask
to mark some macroblocks unconditionally changed. This might (??) be
faster than -vop crop for reducing wasted memory bandwidth when there
are silly black borders to remove -- from my experience the crop
filter makes things slower if anything.

Rich