Signal coding

A method of coding a coded data stream, comprising:

• generating the coded data stream comprising respective groups of packets, generated by a source coder and a first header, generated by a SSI header generation unit and multiplexed by a multiplexer to be present at a beginning of the coded data stream, the first header being associated with a first packet of the group of packets and comprising source significance information including an offset indicating a start position of the associated first packet;
• including, using an intermediate coder, a further header in the coded data stream;
• replacing, using the intermediate coder, the first header at the beginning of the coded data stream;
• and
• updating, using the intermediate coder, the offset in the first header.

A method of channel encoding, the method comprising:

• receiving a coded data stream, in which source significance information has been included, the source significance information indicating desired protection rates of respective parts of the coded data stream;
• identifying, using a controller, the source significance information in the coded data stream;
• and
• channel coding, using a channel encoder, respective parts of the coded bit-stream with respective protection rates under control of the source significance information.

A method of channel decoding, the method comprising:

• receiving, using a demodulator, a channel coded data stream, in which source significance information has been incorporated, the source significance information indicating protection rates of respective parts of the channel coded data stream;
• identifying, using a controller, the source significance information in the channel coded data stream;
• and
• channel decoding, using a channel decoder, respective parts of the channel coded data stream with respective protection rates under control of the source significance information.

A device, comprising:

• means for coding a coded data stream, the coded data stream comprising respective groups of packets and a first header present at a beginning of the coded data stream, the first header being associated with a first packet of the group of packets and comprising source significance information including an offset indicating a start position of the associated first packet;
• means for including a further header in the coded data stream;
• means for replacing the first header at the beginning of the coded data stream;
• and
• means for updating the offset in the first header.

A channel coder comprising:

• means for receiving a coded data stream, in which source significance information has been included, the source significance information indicating desired protection rates of respective parts of the coded data stream;
• means for identifying the source significance information in the coded data stream;
• and
• means for channel coding respective parts of the coded bit-stream with respective protection rates under control of the source significance information.

A channel decoder comprising:

• means for receiving a channel coded data stream, in which source significance information has been incorporated, the source significance information indicating protection rates of respective parts of the channel coded data stream;
• means for identifying the source significance information in the channel coded data stream;
• and
• means for channel decoding respective parts of the channel coded data stream with respective protection rates under control of the source significance information.