Re: v4l interface questions

[Gerd Knorr <kraxel@bytesex.org>]

Pavel Machek wrote:
>  Hi!
>  
>  I have few questions about v4l api.
>  
>  I have device (vicam == usb 3com homeconnect camera), which would like to
>  fit into v4l framework. But... mmap is not really native operation for
>  usb. Should I emulate it, or just return unsupported and expect
>  applications to use read()?

IHMO applications should be able to fallback to read() if mmap() doesn't
work.

>  Similar problem is there with formats. vicam has some really strange
>  formats. Should I do conversion in kernel?

Probably.  The driver should support at least one of the standard
VIDEO_PALETTE_* formats.  It is fine to pick one which comes close to
the native format of the camera, there is no need to support _all_
formats.

>  Is there some usermode program that can handle camera without mmap
>  ability and can support arbitrary screen sizes + 16bpp grayscale?

8bpp grayscale should be no problem with xawtv.  I'd suspect you will
not find any app which can deal with 16bpp, there isn't even a
VIDEO_PALETTE_* #define for this ...

  Gerd

-- 
Damn lot people confuse usability and eye-candy.