A programming technique that uses two buffers to speed up a computer that can overlap I/O with processing. Data in one buffer is being processed while the next set of data is read into the other one.

In streaming media applications, the data in one buffer is being sent to the sound card and/or display adapter, while the other buffer is being filled with more data from the source of the material (Internet, local server, etc.).

When video is displayed on screen, the data in one buffer is being filled while the data in the other is being displayed. Full-motion video is speeded up when the function of moving the data between buffers is implemented in a hardware circuit rather than being performed by software. See video accelerator.