[FFmpeg-devel] [PATCH] libavdevice: v4l2: use libv4l2 when requested.

Måns Rullgård mans
Thu May 13 22:25:48 CEST 2010

Luca Abeni <lucabe72 at email.it> writes:

> Hi Ronald,
> On 13/05/10 21:23, Ronald S. Bultje wrote:
>> Hi,
>> On Thu, May 13, 2010 at 3:17 PM, Konstantin Pavlov<thresh at altlinux.ru>  wrote:
>>> This adds support for numerous pixfmts used in web cameras through
>>> libv4l2.
>> I'm not particularly in favour of random external libXYZ thingies,
>> this goes for any XYZ that will soon be irrelevant, unmaintained and
>> will take a SoC student to properly integrate into FFmpeg after that.
> As far as I can see, this libv4l dependency is optional (if the
> library is not installed, we can still compile the good old code). So,
> I think this should not be a problem...

I am fundamentally opposed to using that library at all.  Period.

It is doing decoding/conversion in a _demuxer_ context, which is at
odds with FFmpeg design principles.  What's more, it does this by
means of a shoddy external library.  Worse still, the patch is a hack.

> I agree that the correct solution would be to add support for bayer
> (or whatever it is) in libswscale or libavcodec, and if/when I get a
> webcam which requires it I'll implement the right thing.

Wouldn't a sample capture be enough?  Or did you mean you'll implement
when you need it yourself?

> But for now there are people who seem to want to use libv4l (and do
> not want to use LD_PRELOAD, for some reason...). Since the patch is
> not intrusive, I think it can be ok (modulo the fact that someone has
> to review the configure part). No?

Then the configure part is rejected.  It uses pkg-config.  I didn't
check for other issues.

M?ns Rullg?rd
mans at mansr.com

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