On 2010-10-14 12:38, Jma/celeonet wrote:
Would you recommand a specific analog grabber card that works fine with Mac ?
A few years ago exactly the same issue led me to finally switch to Linux. At that time it seemed that I couldn't do what you want to do on a Mac. I don't imagine the situation has changed much, good frame-grabbers are used in industrial control and other specialised applications, and that certainly is not Apple territory.
Maybe there are other usb or firewire options available now with enough quality and reasonable latency. The latency you speak of is specific to DV, as you say it is a protocol designed for reliable transfer from camera/tape to computer .. this was very important to Apple and Sony at the time.
Note the sample rate of video is the frame rate. Unless you go for rather expensive very high frame-rate capture devices, which are certainly available, the camera will only be capturing each pixel every 40ms, and even if you processed that information line by line it would be difficult to get any reasonable analysis before a whole frame was present. This leads to unavoidable latencies much longer than audio ones.
Simon