Hi, I'm writing an application where I'm capturing from all four inputs on my bttv card (generic 4-port card). Presently I use VIDIOCMCAPTURE & VIDIOSYNC to start capturing/sync and then VIDEOCSCHAN to switch channels before continuing the loop. That works fine, but the frame rates are quite low - if I capture from only one channel then I can make use of double buffering and get far higher capture rates. What I've tried is to modify the driver so that rather than stop/start the capture process its capturing all the time into four distinct buffers by using the same technique for double buffering, but instead having four buffers, one for each source - when it's captured into the last buffer, it restarts on the first - so the risc program never stops. Now that obviously works fine until I start to attempt to channel switch after each buffer is filled - I expected to get synchronization problems and the point of the email is to ask is there any way I can force a synchronization to achieve my goal? I've experimented with adding additional risc instructions at the end of the capture cycle to see if I could force a small delay before capturing the next frame and then get the fifo to re-sync to allow for the channel switch (it didn't work) - but frankly I'm a bit out of my depth here and don't really know if its feasible in the first place. Its very frustrating as sometimes all four images sync up and for a while and I get 4 seperate images at double the frame rate I'm currently getting - so it looks tantalizingly possible. Is what I'm trying to do possible? Any help gratefully accepted. Thanks, Glen P.S I'm using a 2.2.20 kernel and the standard bttv driver that comes with it (I've looked at the latest bttv for 2.4 from sourceforge and didn't think it added anything that would help me in my problem).
