[mythtv] [mythtv-commits] Ticket #2649: Opengl video renderer

Andrew Lyon andrew.lyon at gmail.com
Tue Jun 5 00:23:14 UTC 2007

On 1/25/07, Mark Kendall <mark.kendall at gmail.com> wrote:
> > What do you mean by "progressive scan versions of onefield, linearblend and
> >  kerneldeint"?
> (My apologies if this sounds like an egg sucking lesson)
> They are frame rate doubling deinterlacers, taking each field in turn
> and using different methods to guess the data in the missing rows to
> produce a complete frame. If there is no motion detected, they just
> use the data from the other field (i.e. 'perfect' quality). Otherwise,
> linearblend interpolates the missing data from the rows above and
> below, kerneldeint takes a view based on certain pixels above, below
> and in the next and previous frames and onefield just uses the data
> from the current field.
> The latter is effectively an 'intelligent' bobdeint - it only 'bobs'
> when motion is detected rather than applying it to the entire picture.
> So no more flickering text etc.
> Personally, I think the kerneldeint version gives the best results but
> it can definitely be improved upon with better motion detection and
> using edge detection/motion compensation techniques.
> > What are your prospects in fixing the top-field deitnerlacing issue?
> Easy enough - do you have some bottom field first samples that I can test with?
> > Does this include a higher quality resize like has been discussed on
> > this list before? (ie SD recordings and DVD playback resizing to 720p
> > or 1080p resolution with all the filter goodies you seem to be
> > implementing)
> That's the plan. I'm just not sure how realistic it is yet. Assuming
> quality is your objective, you'll want to use the best progressive,
> deinterlacer (GPU demanding and double frame rate), followed by a
> scaling operation (haven't figured out yet whether this is a simple
> linear/bilinear scale or more complex), followed by applying some sort
> of convolution kernel on your now much larger image. That last stage
> is going to be really hard on your graphics hardware - to the extent
> I'm even wondering whether it will run in realtime on reasonable
> hardware.
> > I've got a 6200TC on my dedicated frontend, which currently runs
> > 0.20-fixes, is your work dependent on being compiled with SVN?
> The patches are against the mythtv-vid branch.
> > Finally, Thanks for your work! this looks to be some amazing
> > advancements for us HDTV users.

I changed to mythtv-vid today and I am really pleased with the opengl
osd and general video quality improvement, my display is 37" 1920x1080
(Sceptre X37) driven by GeForce 7600GT, as you can imagine the
upscaled SD OSD wasnt all that visually appealing, the opengl one
really is a huge improvement.

Thanks for the hard work.


> My pleasure!
> Mark
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