[MPlayer-dev-eng] Help with MMX asm code

[Jason Tackaberry]

On Thu, 2003-10-23 at 09:44, Billy Biggs wrote:
>   So where is your alpha channel, or is it an opaque forground with just
> a blend parameter, or is the alpha channel in a separate buffer?

In fact it is both.

I load the image as RGBA which gets converted to YUVA (4:2:2:4).  There
is also a separate alpha parameter that applies to the whole image that
acts as a multiplier for each byte in the alpha channel.  The idea is to
allow fading in/out images while still preserving the image's alpha
channel.

> application.  So I just have everything as 32bit pixels until the
> output.  It's also nice because any 4:4:4:4->4:4:4:4 routines can be

For my purposes, I want to store the image that in the optimal format to
make blending with YUV the most efficient.  My intuition is that the
best format would be YUVA, but maybe there's a better way?

Jason.