Capturing in Different IIDC modes

[Steve Sisak]

At 3:01 PM -0500 2/7/05, Peter Carr wrote:
>I'm trying to capture from a Fire-i camera in YUV 4:4:4 @ 160x120. 
>I'm not sure what function calls (and associated parameter values) I 
>need to make to accomplish this.

You need to pas the appropriate compressType to VDSetCompression()

For the standard IIDC YUV types, we are currently using:

enum
{
    kIIDCYUV411Format = 'UYV1',   // uyyv yyuy yvyy (8 pixels)
    kIIDCYUV422Format = 'UYV2',   // uyvy uyvy uyvy (6 pixels)
    kIIDCYUV444Format = 'UYV4'    // uyvu yvuy vuyv (4 pixels)
};

for these compressDepth does not matter -- pass 0

If you want 24-bit RGB, request 'raw ', depth=24

For 8-bit grayscale, you can either request 'raw ', depth=40 (but 
note that black=255, white=0) or 'b08g', which should return standard 
gray.

pass the result VDGetActiveSourceRect() to VDSetDigitizerRect() to 
request full frame video (no cropping).

The ratio of DigitizerRect to ActiveSourceRect controls cropping
The ratio of DigitizerRect to BoundsRect       controls scaling

>Additionally, do I need to setup a GWorld with the same specs as the 
>digitizer settings when I decompress the frames?  If my bounds 
>aren't 160x120 at YUV444, will the GWorld resample the data from the 
>digitizer buffer to make it fit?

This is handled at the layers above -- what you probably want to do 
is look at Kevin Marks' MiniMung example, which lets you look at 
'compressed' data as it goes by.

As of 1.1b43, We install some codecs and transcoders for the IIDC 
native types, plus RGGB Bayer so you can see a preview while you're 
recording in camera native format.

>Finally, I'm interested in analyzing the images in real time.  As a 
>result, I'd like to use the altivec extensions.  Should I decompress 
>the digitizer's image buffer into a vector array instead of a 
>GWorld?  If so, what's the best way to do this?

Either use the techniques in MiniMung to access the data directly as 
it goes by or talk to the vdig directly. I'd start with the former 
until you're comfortable.

HTH,

-Steve
-- 
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Steve Sisak, CTO                                 steve.sisak at ioxperts.com
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