[FFmpeg-devel] [PATCH] Add VDA support to ffmpeg

Michael Niedermayer michaelni at gmx.at
Tue Jul 24 22:48:54 CEST 2012

On Mon, Jul 23, 2012 at 04:02:07PM -0400, compn wrote:
> On Sat, 21 Jul 2012 18:11:35 +0200, Sebastien Zwickert wrote:
> >
> >On Jul 19, 2012, at 7:47 AM, Hendrik Leppkes wrote:
> >
> >> On Thu, Jul 19, 2012 at 1:08 AM, Xunzhen Quan <quanxunzhen at gmail.com> wrote:
> >> 
> >>> 
> >>> I think that HWAccels are just used to do some complex mathematical
> >>> computing acceleration, but VDA is an all-in-one hardware acceleration
> >>> api, which supply only four functions: create decoder, destroy decoder,
> >>> decode and flush. So I think that it should be wrapped as a Decoder
> >>> rather than a HWAccel. And if you think it makes code bload, I suggest
> >>> to just remove the corresponding HWAccel sinceno one seems to be
> >>> using it.
> >>> 
> >>> 
> >> […]
> >> and i've also been told that the VDA HWAccel does also work fine.
> >> All of these you can see in use in for example VLC (including VDA,
> >> according to j-b). They are also not doing "complex mathematical
> >> computing", but high-level bitstream decoding. The codec feeds it full
> >> frames, and not only some math tasks to do.
> >
> >Right. Here is a VLC build with VDA support enabled that links against the 
> >current implementation of VDA HWAccel.
> >http://bit.ly/Noyw3m
> >
> >Note that you should activate manually the use of video acceleration in VLC
> >settings by enabling the Hardware decoding option (Show All -> Video decoders
> >-> FFmpeg). 
> >Some extra info are available on my wiki on github :
> >https://github.com/dilaroga/ffmpeg-vda/wiki
> >
> >So is the current implementation working fine ? Almost :) Indeed, the playback is
> >flickering when VLC starts playing a movie with VDA and is stuttering  when we
> >seek in the stream during about 1 second cause of the VDA decoder is running
> >in asynchronous mode…
> >And my bad, it is possible to use the decoder in synchronous mode and this fixes
> >flickering and stuttering issues. Moreover, it brings a smaller, simpler and proper
> >codebase. I'll provide patches in this way ASAP.
> >The following link is a VLC build with VDA support enabled that links
> >against the VDA HWAccel that runs VDA in synchronous mode.
> >This build just works fine with VDA HWAccel.
> >http://bit.ly/Pu3KFa
> so can this patch be applied until someone hacks up the proper way in
> mplayer ? its not that much 'bloat' ...

do we have a volunteer to maintain this code ?
do we have a volunteer to setup and run fate on a box with the needed
hw and change some fate test to actually test this decoder ?
then i think theres nothing against applying this if its moved to a
seperate file (it doesnt belong to hwacel)

It would help simple players that dont directly support hwaccel but
OTOH, it will not provide the same performace that hwaccel can (for
normal hardware & a video player)

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When the tyrant has disposed of foreign enemies by conquest or treaty, and
there is nothing more to fear from them, then he is always stirring up
some war or other, in order that the people may require a leader. -- Plato
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