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

[Ivan Kalvachev]

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). Or better not. I'm making
rewrite of vo_svga so i don't need the it.
Oh i've nearly forgot, the the svgalib's vga_drawscansegment() uses
struct for caclulating bits to be writen in the plane banks, it is not
very fast anyway, so this format just wastes space and speed.

Ivan Kalvachev