On Wed, 25 May 2005, Dik Takken wrote:
> On Tue, 24 May 2005, Steven M. Schultz wrote:
>
> > "2" means 4:1:1 - and I thought you were dealing with PAL DV which is
> > one of the 4:2:0 variants.
>
> Ah, so y4mscaler only needs to convert between the PAL-DV variant of 4:2:0
> and the PAL-MPEG2 variant that all MJPEG tools van handle. The stories
100% correct.
> about using the "-i 2" switch that I read about on this list only apply
> to NTSC video. Hmm.. Confusing stuff, this is... :)
Yes, or more accurately to 4:1:1 video. If you happen to have
(and I thought there was some 625line/"PAL" gear that used 4:1:1)
4:1:1 then "-i 2" would be helpful.
The '-i 2' option was added so that 4:1:1 users could bypass
smil*/kino/libdv's 4:1:1 to 4:2:0 conversion (which isn't the greatest
quality) and allow the use of y4mscaler to do the 4:1:1 -> 4:2:0
resampling.
> > I think that "-i 2" is forcing smil2yuv to treat PALDV data as 4:1:1
>
> That sounds like what it looks like.. Guess that must be it.
Yep - I'm quite sure that's what is causing your problem.
> > y4mscaler -O chromass=420_MPEG2 -S option=sinc:4 | \
To be quite explicit you could add a "-I chromass=420paldv" to make it
very clear why the y4mscaler line is present:
y4mscaler -I chromass=420paldv -O chromass=420mpeg2 -S option=sinc:6
(I don't think the number of taps in the filter is critical - for some
(forgotten) reason I've settled on 6 when using the sinc kernel).
> Will try that as soon as I get home.
It'll work fine :)
Cheers,
Steven Schultz
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