[MPlayer-dev-eng] What is the format of 4bpp? (postproc/yuv2rgb related)

[Michael Niedermayer]

Hi

On Wednesday 29 January 2003 21:18, Ivan Kalvachev wrote:
> Well this quesion may sound silly but it is not.
> One could suggest that 4bpp mode will use one byte for 2 pixels. This
> way  the stride will be about half width (or more).
> Well the yuv2rgb functions don't think so. They use the svga's vga_draw*
> packing that is one byte for one pixel! You could image what happens
> when vf_scale calls yuv2rgb, and when the vo_ system fills the mpi with
> "right" values -> screen corruption (2 images overlaped , one is shifted
> by half size).
> My letter is mainly to ask, what format should the bgr4/rgb4 be? I think
> that the normal behavior (2 pixels in byte) should be used. Well I
> cannot fix the yuv2rgb scaller.
> Anyway for vo_svga the old (1 pixel per byte) conversion should remain
> (it may need a new  img_format(e.g. PLT4).
IMHO we should not change the meaning of the formats, instead adding a new 
RG4P (rgb4 packed) is IMHO better

[...]

Michael