[PD] gem pdp and yuv

[chris clepper]

On Jun 19, 2005, at 6:25 AM, etienne deleflie wrote:
>
>
>>> 2) when Gem is in yuv mode, is it 24 bits per pixel .. or is it 16 
>>> bits per pixel, as in YUV4:2:2 .... where 2 adjacent pixels share UV 
>>> data ?
>>>
>> The standard YUV-mode in Gem is YUV422 (at least the code says that) 
>> and one
>> pixel is 8 bit.
>>
> 8 bits per pixel?  how does that work?
> do you mean each value is 8 bits ..... in which case one YUV 4:2:2 
> pixel takes up 24 bits?

It's standard 2vuy packing of 8 bits per U Y V Y.  Each pixel has a 
full 24 bits of data, but only requires 32 bits of storage for two 
pixels (which of course you already know since you and Chris K taught 
me this many years ago!).

On OSX, YUV is the default colorspace for GEM, while Windows and Linux 
default to RGBA.