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Re: V4L2_PIX_FMT_RAW

On Thu, Feb 21, 2008 at 12:20 AM, Thomas Kaiser
<linux-dvb@xxxxxxxxxxxxxxx> wrote:
>
> H. Willstrand wrote:
>  > On Wed, Feb 20, 2008 at 11:12 PM, Thomas Kaiser
>  > <linux-dvb@xxxxxxxxxxxxxxx> wrote:
>  >> Daniel Glöckner wrote:
>  >>  > On Wed, Feb 20, 2008 at 10:11:36PM +0100, Thomas Kaiser wrote:
>  >>  >> H. Willstrand wrote:
>  >>  >>> Well, it can go ugly if one piece of hardware supports several "raw"
>  >>  >>> formats, they need to be distinct. And in the end of the day the V4L2
>  >>  >>> drivers might consist of several identical "raw" formats which then
>  >>  >>> aren't consolidated.
>  >>  >> I don't really understand what you try to say here.
>  >>  >
>  >>  > Think about an analog TV card.
>  >>  > In the future there might be one where RAW could mean either sampled
>  >>  > CVBS or sampled Y/C. The card may be able to provide the Y/C in planar
>  >>  > and packed format. It may be capable of 16 bit at 13.5Mhz and 8 bit at
>  >>  > 27Mhz, ...
>  >>  >
>  >>  > If we start defining raw formats, there needs to be a way to choose
>  >>  > between all those variants without defining lots of additional pixel
>  >>  > formats.
>  >>  >
>  >>  > Maybe an ioctl VIDIOC_S_RAW where one passes a number to select the
>  >>  > variant. An application would then have to check the driver and version
>  >>  > field returned by VIDIOC_QUERYCAP to determine the number to pass. This
>  >>  > way drivers may freely assign numbers to their raw formats.
>  >>
>  >>  Yeh, That's something I mean.
>  >>
>  >
>  > Okay, suppose we have pixel formats and raw formats. Comparing with
>  > digital cameras raw usually means non processed image in a proprietary
>  > format. What do we mean here?
>
>  I talk about webcams. But It looks like you don't get the point.
>  A ISOC stream can be received, then we forward this to user space! That's it.
>
>  This has nothing to do with pixel format, just deliver  the stream from the cam
>  to user space, That's all what I won't.
>  I think raw means raw, "not manipulated"! Oder in Deutsch Roh equals raw, which
>  means "not touched".
>
>  You get the point?
>

Yes, I understand what you want to achieve and that's fine.

Still, the hardware produces an image, the image has a format (either
a well know or proprietary), the image might or might not been
processed by the Webcam, etc.

What's the problem with having a name of the formalized data in the
video stream? ie raw do not mean undefined.
I don't see how separate RAW ioctl's will add value to the V4l2 API,
it fits into the current API.

Cheers,
Harri

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