logiWIN supports double and triple buffering. Double/triple buffering is the use of two (double) or three (triple) buffers in video memory to hold an output image, so that the 'reader' (for example CPU or video controller) sees a complete (perhapos old) version of the image, rather than a partially updated one. This enables flicker-free reproduction of an input video stream, but increases reproduction latency.
If the system has two buffers: 0 and 1, the 'reader' can read an image from buffer 1, while logiWIN draws a new image into buffer 0. When the 'reader' finishes reading buffer 1 it has to wait until logiWIN finishes writing to buffer 0. Buffer switching has to be done in video input's vertical blank period before swapping the buffers. This method can be done only if the 'reader' can wait (can be stopped), like CPU. Otherwise, if both streams ('reader' and logiWIN) are free-running (usually with different refresh rates), double buffering is not good enough. This is achieved by using triple buffers for video input and video output. |