[mythtv] Improving 50Hz video on a 60Hz display

[Martin Long(myth)]

On Wed, January 2, 2008 7:55 pm, James Buckley wrote:
> On 27/12/2007, Ed W <lists at wildgooses.com> wrote:
>>
>>
>> > Now I don't know too much on how the opengl playback method works, but
>> > I guess that with it we can use many of the features provided by
>> > opengl (at the expensive of gfx card processing). At the moment
>> > playing 50Hz video on a 60Hz display causes some frames to be
>> > duplicated (to make up the missing time). However I was thinking that
>> > maybe 2 frames could be 'mixed' together, by setting each frame to
>> > have a transparency level. The alpha level could be dynamic, which
>> > would allow to be adjusted per frame to achieve the best possible
>> > picture.
>>
>>
>> It seems the better commercial players blur frames together to reduce
>> jitter...
>>
>> Some nvidia cards can do 50Hz though if you disable the various check
>> features in the driver...
>>
>> (looking for 24Hz features myself...)
>
>
> Almost any framerate can be achieved with the right modelines, but
> sometimes
> TV's are just too picky about input, or in some cases (such as mine), it
> just won't actually accept 50Hz video over DVI. I just thought that with
> the
> new opengl interface, we could open up some features...
>

I would go along with this. I connect using VGA, and my TV will only do
60Hz as full res, so it's really jerky. Plus if you're watching
time-stretch, or NTSC on PAL or vice versa you're also going to suffer. If
blending really does help, and doesn't result in horrible artifacts (I'm
not really sure how they would manifest in this case), then I think this
idea is worth a shot.

Saying that, I don't seem to be able to get much joy from the opengl
method on my NVidia yet.