On Wednesday 19 December 2007 18:23:55 Richard Atterer wrote: > On Wed, Dec 19, 2007 at 05:36:09PM +0100, Hans Verkuil wrote: > > I think that this might be an ideal opportunity to develop a v4l2 > > library that can be used by applications to access v4l devices. > > Oh yes, very much agreed! > > The library should > - provide a single API to access both v4l1 and v4l2 > - maybe allow non-v4l devices (network cams) > - make it easy to get a picture from any detected cam in a > particular format (and e.g. perform MJPEG decoding or resolution > rescaling along the way) > - provide a standard plug-in API (maybe gstreamer-like) for the > video stream. This is necessary to support stuff like software > autofocus for some Logitech webcams, or for turning the picture > upside down (necessary for some webcams built into notebooks) > - extend the plugin API to controls, e.g. allow automatic framerate > (i.e. shutter speed) selection by user-supplied software as well as > framerate selection by the webcam's firmware. > - provide a standard way for controls like brightness, focus, motor > controls. Emulate controls like brightness in software - standard API to scan for channels (TV & radio), preferably also setting a standard config format containing the channel info. - simple video format conversions for the various YUV/RGB formats. - storing and retrieving card preferences (e.g. recording volume, brightness, MPEG encoder settings, etc.) The biggest initial problem is deciding how low or high level the library will be. I actually think that it might be a good idea to have perhaps two libraries: one for low-level stuff (i.e. just a relatively thin layer on top of v4l) and a high-level library allowing format conversions, etc. Hans > > The following is a start, but AFAICT nothing has happened WRT an > implementation (?): > <http://linuxtv.org/v4lwiki/index.php/V4L2UserspaceLibrary> > > This is a start from a different perspective, quite a bit more > low-level, not enough for many of my requirements above: > <http://www.quickcamteam.net/software/libwebcam> > > Cheers, > > Richard _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
