Bug#735332: mpv: Doesn't use vaapi by default

[Kurt Roeckx]

On Wed, Jan 15, 2014 at 04:31:27PM +0100, Alessandro Ghedini wrote:
> On mar, gen 14, 2014 at 10:09:02 +0100, Kurt Roeckx wrote:
> > Package: mpv
> > Version: 0.3.2-1
> > 
> > Hi,
> > 
> > It seems mpv tries to use vpdau and tries to load
> > libvdpau_nvidia.so by default and fails.
> > 
> > It then tries to use gl instead, which works perfectly.
> > 
> > But I have an intel GPU, and I would make sense to use vaapi
> > instead.  Using -vo vaapi at least seems to work for me.
> > 
> > Would it make sense to try to use vaapi by default?
> 
> Well, generally speaking VA API is kinda bad for video output (e.g. the OSD is
> generally low quality, and in some cases the OSD and subtitles can't even be
> drawn at the same time). I've never really used the VA API backend though, but
> this seems to be upstream's opinion as well.

Both the OSD and subtitles work and seem to be good quality to me
with using vaapi or gl, I can't see the difference and I've tried
hard to look at the difference.  xv on the other hand has blurry fonts,
like it has been scaled up with the rest of the image.

> As for video decoding, you can enable vaapi-powered hardware decoding with the
> opengl backend too (manually using the hwdec=vaapi option, since IIRC it's not
> auto detected).

This clearly reduced cpu usage by a factor of 3-4.

> The only useful thing about VA API video output is probably lower power
> consumption on laptops, but I don't think that's a good enough reason to enable
> it by default instead of, say, the opengl backend.

hwdec=vaapi seems to have a large inpact on cpu usage here,
vo=vaapi seems to not have much effect.


Kurt