| 摘要 |
<p>In an image source for multimedia applications such as networked computer games, a graphics engine (16) generates pixel images one line at a time using a scan-line algorithm and supplies the generated scan lines to an encoder (18) where they are buffered. The encoder codes the buffered pixel data as macroblocks of, for example 16x16 pixels according to MPEG or similar standards. When the graphics engine has sent sufficient scan lines to the encoder, it sends a signal (FLAG) on receipt of which the encoder begins coding the pixel lines as a macroblock line whilst continuing to receive scan lines from the graphics engine (16). To increase encoder efficiency, the graphics engine specifies to the encoder global (GMV) and macroblock (BMV) motion vectors for substantially all or selected ones of the macroblocks of an image respectively. Completed coded macroblock lines may be sent out to a remote user over a data network, with user commands affecting the composition of subsequent frames being received on a back-channel (26) of the network.</p> |
