[mythtv-users] New deinterlacer for perfect image quality when using an interlaced display, mode that matches the source

[Tom Dexter]

On Tue, Apr 7, 2009 at 4:29 AM, Paul Gardiner <lists at glidos.net> wrote:
> Jean-Yves Avenard wrote:
>>
>> Hi
>>
>> 2009/4/7 Paul Gardiner <lists at glidos.net>:
>>>
>>> I'm still none the wiser about this. Probably is worth trying the
>>> backport of Mark's patch again. Also you could try the original patch
>>> with the aternative version of filter function below:
>>
>> Could you publish your changes it as a patch in your existing ticket ?
>
> Yeah, I'll do that. But before anyone takes it on, it would be good to
> see how Tom gets on with it: as far as I can see, my latest version
> should do the same job as the backport of Mark's version (with the
> fix for the lack of the "field" paramater on fixes, that is).
>
> Cheers,
>        Paul.
>

OK...I've done some extensive testing of 1080i playback with the
various versions of this patch.

I'm not sure what was going on the other night when I thought I was
having problems with motion using the modified version of Mark's patch
(mythtv-0.21-field-order.6.patch), but today I watched a ton of 1080i
stuff with it and everything looks great.

When I thought I was seeing problems with motion, it was specifically
(and only) with the final episode of ER I recorded last Thursday.
Even then, my wife really didn't see anything wrong, and I really
didn't give it much of a chance before switching to Bob x2 (until I
could find time to recompile).  If I was in fact seeing anything odd,
it's possible it was something NBC was doing...possibly mixing more
than their usual amount of progressive frames etc...who knows.  The
stuff they do normally causes video to speed up momentarily after
commercials when using Bob x2, so anything's possible.  Unfortunately
I neglected to save that show which would have allowed me to verify
that.

In any case, I watched several other NBC shows with their usual
oddball video and everything looks great.  I can't tell any difference
today between that and Paul's original patch (or the original patch
with the OSD flicker patch).  I watched part of a PBS Nova episode and
it looks simply spectacular.

Sorry for what was apparently a false alarm.

I did have a question about the some differences in filter_func in the
newest (Mark's) version as compared to the original.  While the two
appear to be functionally the same, it appears to me that, in the new
one, there may be cases where the filter is doing additional (and
unnecessary) math.  That is, there appear to be cases when the
variables src and dst2 get calculated and not used, as well as cases
where src gets calculated twice.  The code is arguable cleaner than
the original (less duplicate code), but possibly not as efficient(??).
 From what little I know of what's going on, that seems like a place
were efficiency could be pretty important.  I think that the newest
version actually is using a bit more CPU than the original, though I'd
have to switch back to be sure.

Thanks again to Paul and Mark for this one.  Great stuff.

Tom