[mythtv-users] VDPAU and playback filters

[Dave Badia]

On Thu, Mar 10, 2011 at 9:36 AM, Mark Kendall <mark.kendall at gmail.com> wrote:
> On 10 March 2011 22:24, Dave Badia <dbadia at gmail.com> wrote:
>> I tried applying the invert filter
>> (http://www.mythtv.org/wiki/Using_playback_filters) while using VDPAU,
>> but it doesn't work for me.  If I switch to CPU based output I see the
>> filter take effect.  Is this by design?  Some limitation of VDPAU?
>>
>> I ask because I'd like to implement a new filter, but it won't be of
>> much use if it doesn't work under VDPAU.
>
> None of those filters will work in conjunction with any form of GPU
> based decoding acceleration (e.g VDPAU, VAAPI, DXVA2).  Technically it
> would be possible to implement some post-process filters via OpenGL
> but it's not available with the current implementation. Alternatively
> you could copy the decoded frame back into main memory for filtering
> (which is actually what VLC does) - but that won't come cheap and
> you'll lose much of the VDPAU benefit in the process.
>
> What kind of filter are you looking at?
>
> regards
>
> Mark
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I'm looking for a filter that will flip video vertically so iPhone
videos will display properly (more background info here
http://www.gossamer-threads.com/lists/mythtv/dev/474381).

ffmpeg's libavfilter has a vflip filter, but I assume I can't use that
for the same reasons I can't use myth's filters (I was going to write
a vflip filter in myths filter framework).

I looked at the VDPAU header file and see the following gives a way to
rotate video:
VdpOutputSurfaceRenderOutputSurface
but I don't see that used anywhere in the current code so that doesn't
seem like a realistic approach (for me at least)

I'm new to the video processing/display part of all this... been
digging my way though the code to see how I can fit this in.
Makes sense that the VDPAU decode/filter/output flow keeps everything
on the card and therefore only the VDPAU specific filters can be
applied

Any other approaches that could be use here or is copying back to main
memory the only one?

Thanks for the help
Dave