Transcoder and method used therein

A transcoder for receiving a block based, compressed bitstream of video data and outputting a transcoded bitstream, the transcoder comprising:

• a decoder comprising an input to receive the compressed bitstream, decoding the compressed bitstream to provide a block of video data and block information;
• a controller determining whether a skipped block occurs in the compressed bitstream according to the block information;
• and
• an encoder using a compensation block derived from at least a reference error picture to compensate a current decoded block, and encoding a current compensated block into the transcoded bitstream;
• wherein when a skipped block occurs in the compressed bitstream, the encoder does not use the compensation block to compensate a decoded block corresponding to the skipped block.

A transcoder receiving a block based, compressed bitstream of video data and outputting a transcoded bitstream, the transcoder comprising:

• a decoder comprising an input to receive the compressed bitstream, decoding the compressed bitstream to provide a block of video data and block information;
• a controller determining whether an skipped block occurs in the compressed bitstream according to the block information;
• and
• an encoder encoding the block of video data into the transcoded bitstream;
• wherein when the controller determines a skipped block occurring in the compressed bitstream, the encoder generates a corresponding skipped block in the transcoded bitstream.

A machine-readable medium storing code, which, when executed by a processor, causes the processor to perform the steps of:

• receiving a compressed bitstream of video data;
• determining whether an skipped block occurs in the compressed bitstream;
• and
• storing a compensation block for the skipped block into a corresponding block in a frame buffer without using the compensation block for error compensation when a predetermined condition is met.