Re: [Linux-uvc-devel] Logitech Quickcam for Notebooks Pro

[michel X. <mx...@ma...>]

Le Mardi 31 Janvier 2006 17:07, Binary Xerroz a écrit :
> On 1/31/06, Luc Saillard <lu...@sa...> wrote:
> > On Tue, Jan 31, 2006 at 01:52:47AM +0100, Laurent Pinchart wrote:
> > > > im currently looking through the libng source code (included in the
> >
> > CVS
> >
> > > > version of aMSN, utils/linux/capture/libng), and i really dont know
> >
> > where
> >
> > > > to start. I cant find (or  just blind to) the YUYV converter in the
> >
> > code,
> >
> > > > and assuming i can find it, still not sure where to put the mjpeg
> >
> > decoder
> >
> > > Try to ask the aMSN developers.
> > >
> > > The best solution to that problem would probably to have a v4l
> >
> > user-space
> >
> > > library which would handle decompression in user-space (this would also
> >
> > have
> >
> > > the benefit to make user-space drivers possible).
> >
> > I'm currently trying to change my libpwc to be able to decompress the
> > MJPEG
> > buffer and convert it in YUV420P or RGB24. So perhaps one day, we will
> > have a
> > v4l2 library like in the alsa world. As i've a pretty small decoder, this
> > can
> > be embeded in a lot of applications. But i don't known if more developper
> > will want to use the tiny library, so for the moment, it's just a small
> > pixel format convertion library.
> >
> > Luc
>
> Well the jpeg_decoder function found in utils.h seems to be decoding to
> YUYV (v4l format 411P shows an uglier picture than with format YUYV, so
> this is based on this, even though in the function it says 411 encoding)
>
> Also, <mplayer base dir>/postproc/, contains functions and libraries and
> what not to convert YUYV streams into apparently many others.
>
> Im going to try to find an algorithm from mplayer to convert the YUYV
> stream into i guess YV12  as im told its more umm supported? if i can ill
> add it to my program uvcStreamer and see if it yields any results.

utils.c and utils.h set in uvcview are quick hack to perform YUYV decoding and 
allow people to play with the UVC video class webcams no more no less :)
the jpeg decoding is coming from the GPL bootsplash project with some 
modification as the original one play with rgb components :)
I have try to compile EKiga (thanks for the answer about evolution ) to mutch 
dependancies for me, after evolution i need avahi who need dbus qt4 libdaemon 
gdbm .... sorry Luc i will try EKiga and the tinyjpeg decoder when  Suse 
update a full package :(
-- 
Michel Xhaard
http://mxhaard.free.fr