[no subject]

[Bhupesh SHARMA <bhupesh.sharma@xxxxxx>]

Hi Laurent,

I have a query for you regarding the support and testing of MJPEG frame type in the UVC webcam gadget.

I see that in the webcam.c gadget, the 720p and VGA MJPEG uvc formats are supported. I was trying the same
out and got confused because the data arriving from a real video capture video supporting JPEG will have no
fixed size. We will have the JPEG defined Start-of-Frame and End-of-Frame markers defining the boundary
of the JPEG frame.

But for almost all JPEG video capture devices even if we have kept a frame size of VGA initially, the final
frame size will be a compressed version (with the compression depending on the nature of the scene, so a flat
scene will have high compression and hence less frame size) of VGA and will not be equal to 640 * 480.

So I couldn't exactly get why the dwMaxVideoFrameBufferSize is kept as 614400 in webcam.c (see [1]).

Can you please let me know your opinions and how you tested the UVC gadget's MJPEG frame format.

[1] http://lxr.linux.no/linux+v3.5/drivers/usb/gadget/webcam.c#L232

Thanks,
Bhupesh
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