Transcoding apparatus and method

A method for transcoding coded digital video signals representing blocks of pixels, comprising the steps of:

• decoding inputted encoded digital signals, including steps of
• determining an end-of-block (EOB) position in an incoming block of the encoded inputted signal,
• inverse quantizing the inputted signals,
• determining a discrete cosine transform (DCT) block type based on the EOB position, and
• performing partial inverse DCT computations based on the DCT block type to provide decoded signals;
• and
• encoding the decoded signals.

A method for transcoding coded digital video signals representing blocks of pixels, comprising the steps of:

• decoding inputted encoded digital signals, including steps of
• determining an end-of-block (EOB) position in an incoming block of the encoded inputted signal prior to inverse quantizing,
• inverse quantizing the inputted signals, and
• encoding the decoded signals, including steps of
• determining if an incoming block of the decoded signals is intracoded or intercoded,
• performing a discrete cosine transform (DCT) of the decoded signals by selecting, if the incoming block is intracoded, DCT coefficients from the inverse quantized inputted signals to provide transformed signals, and
• performing a DCT of the decoded signal by computing, if the incoming block is intercoded, selected DCT coefficients located before the EOB position of the incoming block to provide transformed signals.

A transcoder for transcoding coded digital video signals representing blocks of pixels, comprising:

• a decoder for decoding inputted coded digital signals, including
• means for determining an end-of-block (EOB) position in an incoming block of the encoded inputted signal,
• an inverse quantizer for inverse quantizing the inputted signals,
• means for determining a discrete cosine transform (DCT) block type based on the EOB position, and
• an inverse discrete cosine transformer for performing partial inverse DCT computations based on the determined DCT block type to provide decoded signals;
• and
• an encoder to encode the decoded signals.

A transcoder for transcoding digital video signals representing blocks of pixels, comprising:

• a decoder for decoding inputted encoded digital signals, including
• means for determining an end-of-block (EOB) position in an incoming block of the encoded inputted signals;
• and
• an inverse quantizer for inverse quantizing the inputted signal, and
• an encoder to encode the decoded signals, the encoder including
• means for determining if an incoming block of the decoded signals is intracoded or intercoded, and
• a discrete cosine transformer for performing a discrete cosine transform (DCT) of the decoded signals by selecting, if the incoming block is intracoded, DCT coefficients determined from the inverse quantized inputted signals, the discrete cosine transformer performing the DCT by computing, if the incoming block is intercoded, selected DCT coefficients located before the EOB position of the incoming block.