[FFmpeg-devel] [RFC]Nvidia VDPAU patches

Reimar Döffinger Reimar.Doeffinger
Mon Dec 1 16:09:14 CET 2008

On Mon, Dec 01, 2008 at 09:42:25AM -0500, compn wrote:
> can the vdpau api handle decoding most/all h264 resolutions/bitrate etc?

All: that is impossible.
All relevant ones: probably depends on the hardware.

> is ffmpeg asking for a generic decoder instead of a per-profile decoder?

IMO definitely. I do not know for sure what the point of splitting by
profiles was for VDPAU, but I very much doubt it is necessary to expose
this anywhere that does not directly use the VDPAU.
An application might want to be able to get some additional information
about the stream to decide if it should try to use a hardware decoder or
not, but this then should be done in a more generic way.
E.g. the current approach would completely fail is somebody concatenated
a "high" with a "baseline" profile H.264. If this information was
exported in some other way, the application could just seek to different
places in the file and notice such a case if it wanted.
It would also be possible to think of a method where an application
would just decode some random 1% of the file with the software decoder
and based on the actually used features decide what to use.
The PIX_FMT solution in contrast is a dead-end, can not be reasonably extended
and is specific to VDPAU (and as said even there likely to match badly,
I can't imagine that the GPUs possibilities _always_ match _exactly_
with the profiles - actually I'd imagine that is most likely never the

Reimar D?ffinger

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