| 摘要 |
<p> A data processing apparatus (800) has an input (810) for receiving a first and second sequence of frame-based A/V data. A processor (830) edits the two sequences forming a third combined sequence. So-called 'I-frames' are intra-coded, without reference to any other frame of the sequence. 'P-frames' are coded with reference to one prior reference frame, and 'B-frames' are coded with reference to one prior and one subsequent reference frame. The referential coding of a frame is based on motion vectors in the frame indicating similar macro blocks in the frame referred to. The processor identifies frames in the first sequence up to and including a first edit point and frames in the second sequence starting at a second edit point that have lost a reference frame. The processor (830) re-encodes each identified B-frames into a corresponding re-encoded frame by deriving motion vectors of the re-encoded frame solely from motion vectors of the original B-frame.</p> |
