RE: [RFC/PATCH v4 1/4] Changes in include/linux/videodev2.h for MFC 5.1

[Kamil Debski <k.debski@samsung.com>]

Hi,

From: Mauro Carvalho Chehab [mailto:mchehab@redhat.com]
> Em 10-12-2010 01:32, 박정태 escreveu:
> > Hi, Kamil
> >
> > What do you think modification of codec class control ID for MFC as
> > following.
> > 1. Define the CID base for MFC
> > 2. Separate decode & encode controls
> > 3. Separate common & codec-specific controls
> >
> >> Add fourcc values for compressed video stream formats and
> >> V4L2_CTRL_CLASS_CODEC. Also adds controls used by MFC 5.1 driver.
> 
> This is a very bad idea. As much as possible, controls should be
> generic enough
> to avoid us to have the same control provided  by two different
> hardware.
> 
> The only case were a control should be per-driver, is when the control
> is for some
> very specific implementation detail on that hardware, that it is
> unlikely that other
> chipsets will implement it at the same way.
> 

I agree with Mauro. The point of having a general class for codecs
(V4L2_CID_CODEC_CLASS) is reusing same controls for different hardware.
I think that most controls, maybe all, could be used by other hw codecs.

> (snip)

Best regards,
-- 
Kamil Debski
Linux Platform Group
Samsung Poland R&D Center