[MPlayer-users] cropdetect accuracy with mplayer-1.0pre6a
rcooley at spamcop.net
Sat Feb 19 06:08:05 CET 2005
On Fri, 18 Feb 2005 15:33:57 -0500
D Richard Felker III <dalias at aerifal.cx> wrote:
> quite often you'll scale after cropping though, in which case it's
> useless to round crop values.
>From my experience on this list, I've heard from lots of people, and it
seems that most do not scale after cropping.
I personally do not scale most of the time, and when I do, I scale
BEFORE cropping. The performance difference is negligable.
> not the codec matter, rather image formats. basically all the image
> formats used in movies are 4:2:0, meaning that non-even crop offsets
> or sizes are _complete nonsense_,
Yes, I said codec, but meant "format". You'll see that I also mentioned
4:4:4, which is a format in which cropping to odd dimentions makes
perfect sense. No, there aren't many situations where that is
appropriate, but there are some. We could also limit cropdetect to
no-less than multiples of 4 to prevent people working with interlaced
material from shooting themselves in the foot. I just dislike the idea.
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