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V4L2 backward compatibility to V4L1

Thanks for all.

As Willem said, it is hard to get rid of the V4L1 API at application side.
E.g. using of memory buffers is different enough between the 1 and 2 to make
it quite complicate to do the update - at least to me ;-\ This is however
very strategic point of functionality since it may be the one thing actually
including the information from camera that is about to be passed to display,
image formatting/grabbing functionality etc.

At least to me that is the biggest problem - getting to know what in V4L2
actually includes handling of the same information as using of video_mbuf
and video_mmap structs with VIDIOCMCAPTURE. At application side, changing of
these - and the functionality they form - seems to be require changing quite
a lot..

/O

On 5/1/06, Markus Rechberger <mrechberger@gmail.com> wrote: 

Hi,

not sure if it might help, I also implemented v4l1 compatibility in
the em28xx driver and now it works fine even with the v4l1
applications I tested (for example mplayer using the v4l1 driver and
motion)
http://linuxtv.org/hg/~mrechberger/v4l-dvb
If you have any questions regarding this one let me know

Markus

On 5/1/06, wduinker <wduinker@xs4all.nl> wrote:
> I am also struggling. At the moment I am implementing a webcam driver
> for ALI m560x chips. As recommended I implement V4l2, but most viewers
> are using a V4l1 interface. I added the v4l1-compat module call to
> translate the ioctl calls, as suggested and implemented in cx88-video.c.
> Still the overlap in the the ioctl numbers makes it in my mind
> impossible to come up with a satisfactory solution.
>
> Looking at the code of the various webcam drivers it seems hard to get
> rid of the V4L1 api. Does anybody have a suggestion for a clean
> solution, besides writing my own applications again. How can an
> application or a driver tell which api he wants to use?
>
> Willem
>
> Ola Helm wrote:
>
> >The file I mentioned seems to be meant for that kind of purpose. The
problem
> >is I have no clue about how to use it..
> >
> >V4L1 and 2 are - as you said - entirely differnt from each other. It
looks
> >like quite extensive job to transform application with v4l1 calls to
support
> >v4l2.
> >
> >/Ola
> >
> >On 4/20/06, Michał Joachimiak <mjoachimiak@gmail.com> wrote:
> >
> >
> >>Is V4L2 compatible with V4L1 at all?
> >>In OpenCV (
> >>http://www.intel.com/technology/computing/opencv/index.htm)library I
was
> >>using some time ago code for V4L1 and V4L2 was entirely different.
> >>These drivers are different in using so that's the problem, I think
> >>
> >>2006/4/19, Ola Helm <ola.hel@gmail.com>:
> >>
> >>
> >>>Hi,
> >>>
> >>>
> >>>I'm wondering how to use backward compatibility of V4L2 (
v4l1-compat.c).
> >>>To
> >>>me, it seems to be compiled with kernel (object file exists), but
> >>>application using video 4 linux version 1, does not seem to work.
V4L2
> >>>application works nicely. In practise it stops to first VIDICGCAP
since
> >>>
> >>>
> >>it
> >>
> >>
> >>>does not find the capabilities.
> >>>
> >>>Links to old conversations about the topic also welcome, did not find
> >>>any..
> >>>
> >>>/Ola
> >>>--
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> >>>
> >>>
> >>>
> >>
> >>--
> >>Pozdrawiam, Michał Joachimiak
> >>+48 889 404 661
> >>#gg: 1499385
> >>
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