[MPlayer-dev-eng] optimized color space implementation?

D Richard Felker III dalias at aerifal.cx
Sun Mar 7 23:01:18 CET 2004

On Sun, Mar 07, 2004 at 04:28:34PM -0500, Marc Hoffman wrote:
> On Mar 7, 2004, at 12:32 PM, Michael Niedermayer wrote:
> >Hi
> >
> >On Sunday 07 March 2004 15:38, Marc Hoffman wrote:
> >>Is it acceptable to truncate the number of pixels in a horizontal scan
> >>to a multiple of 32 to simplify the vector coding loops?
> >>
> >>e.g. 720 becomes 704.
> >no, either write loops which dont have such a limitation or round up, 
> >and use
> >the c converter for the last line
> Ok can I assume that I always get a multiple of 16 pixels, or is that 
> just a bad assumption as well.

You should just process as much of the image as you can under the
assumptions you want to make, and then make sure the C code handles
the remainder of the image!

> And can i assume an even number of scanlines as well?

IMO you should be able to assume this since 4:2:0 with an odd number
of scanlines makes absolutely no sense.....but I dunno if it's
acceptable for ffmpeg. But if you take the approach I suggested above
it shouldn't matter.


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