[MPlayer-dev-eng] video filter layer

[Rich Felker]

On Sat, Apr 21, 2007 at 01:19:39PM +0200, Michael Niedermayer wrote:
> Hi
> 
> On Sat, Apr 21, 2007 at 09:54:29AM +0200, Reimar Döffinger wrote:
> [...]
> > There are also things like having both MP_IMGFLAG_READABLE
> > MP_IMGFLAG_PRESERVE, seems somewhat questionable to me whether one makes
> > sense without the other...
> 
> IIRC the original idea was that a buffer could be in video memory (preserved
> but slow as hell to read)
> 
> and conditional replenish based codecs just update some pixels but leave the
> remainder unchanged, they also dont read from the buffer so they would
> theoretically benefit from such buffers
> 
> but IMHO its an obscure feature which is pretty unimportant

this actually offers a large performance boost to slow machines
playing low quality 'divx' files, iirc..

anyway i hope you'll take a look at the functional programming
approach to filtering described in my design proposal. it makes all of
these questions irrelevant by relegating the choices about buffer
management to the overall system implementation so that filters and
codecs need not be aware of it (and thus can be used unmodified even
if the filter layer is radically optimized for performance on low-end
systems or simplified for implementations that don't want the
complexity).

rich