What is the difference between raw1394 and video1394 capture?
video1394 capture uses Direct Memory Access (DMA) to pipe camera data directly from the interface card to the computer memory, without copy or processor load (the data does not go through the processor at all.) This allows the maximal framerate to be reached in an efficient way. Video1394 is, in general, the capture mode that you should use. libraw1394 uses libraw1394 to transfer images from the camera to a user-accessible buffer. This is not efficient because it requires copying data between internal and accessible buffers. This seriously reduces the maximum framerate and increases the processor load. In fact, due to other technical reasons the maximum framerate using libraw1394 is 50% of the framerate used by the camera: if the camera sends images at 15fps you will never reach more than 7.5fps [This may need confirmation]. For these reasons raw1394 access is only suitable for applications with limited requirements. It is however simpler to setup and does not rely on an extra module.
