USB based video capture card with API

I am looking for a usb 开发者_JAVA技巧based video capture card (to be used with cctv analog cameras) which comes with an api. An api of sorts would help as I am planning to do some analytics on the video stream.

Any ideas on such a device?

What platform? Pretty much any capture card would work with DirectShow on Windows. On Linux, the usual API is V4L - the hardware compatibility list isn't as extensive on Linux, but most things do work with it.

The only capture boards I know of internal to a PC are PCI capture cards. A USB capture card would limit the data you could capture. For instance if you try to stream video to a USB drive you'll get error messages because USB is too slow. You're better off purchasing an encoder to do what you want. Retail for an analog encoder is as low as 300 dollars and it allows you to connect 4 analog cameras.