Re: V4L2_PIX_FMT_RAW

[Thomas Kaiser <linux-dvb@kaiser-linux.li>]

H. Willstrand wrote:
> On Thu, Feb 21, 2008 at 2:20 AM, Daniel Glöckner <daniel-gl@gmx.net> wrote:
>> On Thu, Feb 21, 2008 at 01:02:39AM +0100, H. Willstrand wrote:
>>  > What's the problem with having a name of the formalized data in the
>>  > video stream? ie raw do not mean undefined.
>>
>>  I thought you wanted to avoid having to define V4L2_PIX_FMT_x for an
>>  exploding number of proprietary formats that are quite similar but still
>>  incompatible. It makes sense for formats that are used by more than one
>>  driver.
> 
> Correct, the number of unique pixel formats should be kept down.
> Again, comparing with digital cameras there are >200 proprietary
> formats and there is a "clean-up" on-going where the "market" is
> aiming for a OpenRAW.
> 
> However, by declaring a generic RAW format (which is then driver
> specific) doesn't help the user mode app developers. Calling a
> multitude of libraries to see if you get lucky might not be a good
> idea.
> 
> Still, I'm suspectious about the definition "raw" used here.
> RAW should mean unprocessed image data:
> * no white balance adjustment
> * no color saturation adjustments
> * no contrast adjustments
> * no sharpness improvements
> * no compression with loss

Yes, raw means "as it is" no stripping, decoding  or removing of SOF headers are 
done in the driver. May be V4L2_PIX_FMT_AII (AII -> As It Is) is the better name?

> 
> So, by looking for similarities in the "raw" formats where available
> there should be a potential to consolidate them.
> 
>>
>>  > I don't see how separate RAW ioctl's will add value to the V4l2 API,
>>  > it fits into the current API.
>>
>>  Yes, it does. Each driver having multiple raw formats just needs a
>>  private control id to select one.
>>
> I was more thinking about the VIDIOC_S_RAW stuff, a VIDIOC_S_FMT
> should do the job.
> I.e. I think there should be strong reasons to break V4L2 API behavior.
> 
> Harri


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