> 1. The YUV from the card (/dev/video32) is not
> YUV420 (YV12) but rather 
> Hauppauge's HM12 macroblock format. It requires a
> routine to manipulate 
> it into YUV420. Not hard, but it has to be done
> before doing anything 
> useful with the frame.

right, but i think writing it back it takes YV12.

> 2. The card delivers a complete YUV frame (518400
> bytes) for each video 
> frame. You'll need some fast reads to get the whole
> frame in time. 
> poll()/select() loops don't really help, as you do
> not have any 
> indication (that I can see) of which byte is the
> first byte of the frame.

you really should read a full-frame at a time.

You don't need to be told which byte in the stream is
which - each frame is the same size - just need to
remember where you are in the stream.

if you can't read fast enough and the card dumps
buffers, i *think* V4L even tells you which byte in
the stream you're reading. could be wrong about that.

> what I can do with my applications. ;) Writing a
> short audio delay to 
> compensate for the video processing wouldn't be too
> difficult.

i believe the card has the capability to adjust the
video -> audio delay on its own. Just need to
test/expose it via ioctls.

-tmk


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