[mythtv-users] New deinterlacer for perfect image quality when using an interlaced display, mode that matches the source
Tom Dexter
digitalaudiorock at gmail.com
Wed Apr 15 14:08:43 UTC 2009
On Wed, Apr 15, 2009 at 5:24 AM, Paul Gardiner <lists at glidos.net> wrote:
> Tom Dexter wrote:
>>
>> OK...I've tested that new change with the 'parity' parameter
>> defaulting to 1 for non-interlaces frames and everything looks great.
>> That definitely seems to be the way to go.
>
> Great news. I think we can go with that version. One of us should
> upload a patch. Shall I, or do you want to?
I just uploaded new versions of both patches with that change.
>
>> One small cosmetic thing I've noticed, and I believe it's been the
>> case with all versions: When I have OSD fade enabled and there's any
>> situation where more than one thing displays via the OSD at a time,
>> the fade caused some video stuttering. One place I tend to see it is
>> if I save my place in the recording...that displays the message saying
>> the position has been saved in addition to displaying the progress
>> bar. When those fade it tends to stutter a bit. I also get a CPU
>> spike when that happens. This never occurs with any single OSD
>> overlay, and also doesn't happen if I disable fading.
>>
>> Very minor for sure. I see that it doesn't happen with bob x2.
>
> That's probably not surprising. I think with bob the OSD is rendered
> to Bob's halfheight buffer. Everything's a lot cheaper with bob.
> You might find the same stutter with yadif. There is some room for
> speeding up field order using faster memcpy. Perhaps should look at
> that sometime.
>
Yea, from what I'm seeing I think that multiple OSD layers trying to
fade is simply maxing out the CPU momentarily. Not surprising. I'd
never even heard of using a faster memcpy. I'm running under Gentoo
specifically compiled for P4...I'm not sure if there's any such thing
available or not. Is that generally a change to glibc or something?
>> By the way, I took the time to do some comparisons between this
>> deinterlacer and bob x2 that I was using before. Wow...the difference
>> is _not_ subtle at all. This thing has definitely cured the one major
>> flaw I've lived with since I built the system two years ago. Great
>> stuff.
>
> I'm still sometimes seeing slight strangeness in motion. And sometimes
> I think I prefer yadif. Certainly rolling text credits show that field
> order is doing exactly what it should, but I wonder whether there are
> periods in normal playback where the mpeg decode is complex, which
> leads to the sync changing rappidly. yadif may cope with that better.
> The other possibility I can think of is that the slight blurring due
> to yadif is sometimes beneficial.
>
> Cheers,
> Paul.
>
It's been much better than anything I've used. From what I remember,
I don't think my frontend will run yadif. It's a 3Ghz P4.
Tom
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