On Saturday 18 November 2006 01:22, Corey Fehr wrote:
> Ok, I realise my mistake now. :) Let the ribbing begin.
>
> The saa7115 registers are affecting the input capture. I suppose that my
> original questions still stand though. What is the device doing the mepg
> decoding and to anoyone's knowledge is it capable of resizing  output on
> the fly?

The decoder itself (iTVC15) can resize the video. You'll need the ivtv-fb 
module loaded though. I'm still running an old ivtv build here, and the 
command to resize the mpeg stream being displayed by the 350 is something 
like this...

ivtvfbctl -d /dev/fb0 -w left=350,top=150,width=250,height=200

I don't think the options really need explaining, though you may need to 
add -v 0 to 'hide' the framebuffer and reveal the video.

With this you can both increase and decrease the output video size. It doesn't 
clip the output, so the window cannot exceed the screen boundary (it will 
adjust the left / top edge if needed). For example, in NTSC if you feed a 
720x480 video into it, you can't make the image any larger, but if you feed 
it a 360x240 video you can make it either larger (up to 720x480) or smaller. 
If the output window is 720x480, then it can't be moved, but make it smaller 
& it can be moved around

There's a limit to how small you can go, but I'm a little fuzzy as to what the 
limit is. The hardware itself limits you to a 1/4 of the source resolution 
horizontally, but the firmware call doesn't appear to allow less than 160 no 
matter what the original size. Vertical scaling is more complex, but the 
firmware limit is around 1/4.

If you bypass the firmware call that sets the output window & start 
manipulating the decoder registers directly, you can avoid some of the 
limitations regarding output size & position, to the point that it's possible 
to zoom in on a specific region of the source video.

-- 
Ian

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