[Nouveau] "Decode videos"

[Jimmy Rentz]

On Tue, 7 Dec 2010 13:58:22 +0000
James Courtier-Dutton <james.dutton at gmail.com> wrote:

> On 7 December 2010 01:07, Jimmy Rentz <jb17bsome at gmail.com> wrote:
> > On Mon, 6 Dec 2010 23:05:10 +0100
> > Xavier Chantry <chantry.xavier at gmail.com> wrote:
> >
> >> On Mon, Dec 6, 2010 at 7:35 PM, Mikhail Ramendik <mr at ramendik.ru>
> >> wrote:
> >> > Hello,
> >> >
> >> > http://nouveau.freedesktop.org/wiki/FeatureMatrix lists "Decode
> >> > videos" as WIP for NV30 and NV40 seies.
> >> >
> >> > As I have an NV44, I would really like to know - what is this
> >> > feature going to be? VDPAU support for these cards, or XvMC, or
> >> > something else?
> >> >
> >>
> >> According to
> >> http://lists.freedesktop.org/archives/nouveau/2010-August/006142.html
> >> and the following mails/patches : XvMC.
> >>
> >> Not sure what is possible on nv40 but that subject was discussed
> >> quickly here:
> >> http://lists.freedesktop.org/archives/nouveau/2010-May/005726.html
> >
> > Initially I would say XVMC.  VDPAU expects full hw bitstream
> > decode.  XVMC only does decode starting at idct/mb.  I am guessing
> > it is possible to support VDPAU by doing the earlier stages in
> > software then handling the reset to hw.  Well, unless someone
> > figures out some way to handle the full pipeline in hw via shaders
> > which is something I have no time or knowledge.
> >
> 
> I think it would be better if one could do vdpau in software and then
> initially offload the idct/mb to the hardware.
> The reason being vdpau supports mpeg2 and mpeg4, XVMC only supports
> mpeg2.

Yes, XVMC is very old and some software (mythtv for one) are
removing support for it.  There are some initial VDPAU stubs in the
mesa.pipe-video patch but they don't do anything but support querying
caps,etc and not decode/presentation.