>-----Original Message----- >From: Ronald Bultje [mailto:rbultje@xxxxxxxxxxxxxxxxxxx] >Sent: 21 March 2002 14:38 >To: video4linux-list@xxxxxxxxxx >Subject: Re: editing? > > >On Thu, 2002-03-21 at 14:10, Joe Burks wrote: <SNIP> >> How many current v4l applications support gamma correction? How do I express >> the need for this sort of post processing to the v4l application? Why aren't >> the application developers pumping out more v4l apps with advanced post >> processing capabilities? How about obvious postprocessing tasks like >> rotation? It's pretty easy to rotate a camera 90 degrees to get better scene >> composition, few v4l apps have that feature. Heck my live webcam is >> mounted to a bracket on the ceiling, that image needs 180 degrees of >> rotation. If I wanted to stream live video from that camera, it'd look >> horrible. > >So, if it isn't there, hack it in the applications. But don't let the >driver or quasi-driver (libv4l) do it. What about closedsource apps (not >that we care) that have terribly fast asm/mmx/sse-algorithms (but >proprietary). Should we just make their live impossible? I've been following the discussion with interest and if I've understood the various posts correctly the problem is that some applications don't do gamma correction etc which is required by some users. As far I understand, it is the case that all kernel drivers should ideally be as minimal as possible while providing a suitable standardised cross device interface and, possibly non-standard access to unique hardware capabilities (definitely a difficult compromise :-) One solution is to provide a common library for applications to use in user space to provide the requested video manipulations i.e. make the library easy to incorporate and hope most applications make use of it. Is a possible solution to in effect use a V4L dummy driver, which redirects application requests to a user space video processing module, which intern accesses the real video device via v4l? Any manipulations can therefore be done on the image, with out the application software needing to be changed. Dave ---------------------------------------------------------------------------- ----------------------- This e-mail is intended solely for the addressee. It may contain private or confidential information. If you are not the intended addressee, you must take no action on it nor show a copy to anyone. Please reply to this e-mail to highlight the error. Opinions and information in this e-mail which do not relate to the business of The Nottingham Trent University shall be understood as neither given nor endorsed by the university.
