Signal coding

• US 20020012360A1
• Filed: 07/17/2001
• Published: 01/31/2002
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Olivieri, Stefano, Coppola, Giuseppe
• Granted Patent: US 7,583,693 B2
• Time in Patent Office: Days
• US Class Current: 370/473
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics

Abstract

The invention provides signal coding, wherein the signal is source coded to obtain a coded data stream, and source significance information (SSI) is included into the coded data stream, the source significance information (SSI) indicating desired protection rates of respective parts of the coded data stream. In this way, a channel encoder may obtain the source significance information (SSI) from the coded data stream, which is advantageous in presence of intermediate network layers. Preferably, the coded data stream comprises respective packets, the being included in respective headers associated with the respective packets, a given header indicating desired protection rates for respective parts (p_iⁿ) of the associated packet. In order to provide easy detection of the source significance information (SSI), a first header (SSI¹) is placed at a beginning of the coded data stream. Alternatively, the first header (SSI¹) is provided with an identifier.

Claims

1. A method of coding a signal, the method comprising:

source coding (10) the signal to obtain a coded data stream;

including (11,12) source significance information (SSI) into the coded data stream, the source significance information (SSI) indicating desired protection rates (r_iⁿ) of respective parts of the coded data stream.

2. A method as claimed in claim 1, wherein the source significance information (SSI) comprises respective lengths (Δ

_l^L,n) of the respective parts of the coded data stream.

3. A method as claimed in claim 1, wherein the coded data stream comprises respective packets, the source significance information (SSI) being included in respective headers (SSIⁿ) associated with the respective packets, a given header (SSIⁿ) indicating desired protection rates (r_iⁿ) for respective parts (p_iⁿ) of the associated packet.

4. A method as claimed in claim 3, wherein an offset (Δ

_ofs^l,n) is included in the given header (SSIⁿ), the offset (Δ

_ofs^l,n) indicating a start position (Δ

₁^l,n) of the associated packet.

5. A method as claimed in claim 3, wherein the coded data stream comprises respective groups of packets, in which method a first header (SSI¹) associated to a first packet of the group of packets is placed at a beginning of the coded data stream.

6. A method as claimed in claim 3, wherein the coded data stream comprises respective groups of packets, in which method a first header (SSI¹) associated to a first packet of the group of packets is provided with an identifier (id).

7. A method as claimed in claim 6, wherein the identifier (id) is placed just in front of the first header (SSI¹).

8. A method of coding (13) a coded data stream, the coded data stream comprising respective groups of packets and a first header (SSI¹) present at a beginning of the coded data stream, the first header (SSI¹) being associated with a first packet of the group of packets and comprising source significance information including an offset (Δ

_ofs^l,1) indicating a start position of the associated first packet, the method comprising;

including a further header (h(l)) in the coded data stream;

replacing the first header (SSI¹) at the beginning of the coded data stream; and

updating the offset (Δ

_ofs^l,1) in the first header (SSI¹).

9. A method of channel encoding, the method comprising:

receiving (14,15) a coded data stream, in which source significance information (SSI) has been included, the source significance information (SSI) indicating desired protection rates (r) of respective parts (p) of the coded data stream;

identifying (14) the source significance information (SSI) in the coded data stream; and

channel coding (15) respective parts of the coded bit-stream with respective protection rates (r) under control of the source significance information (SSI).

10. A method of channel decoding, the method comprising:

receiving (17) a channel coded data stream, in which source significance information (SSI) has been incorporated, the source significance information (SSI) indicating protection rates (r) of respective parts (p) of the channel coded data stream;

identifying (18) the source significance information (SSI) in the channel coded data stream; and

channel decoding (19) respective parts of the coded bit-stream with respective protection rates (r) under control of the source significance information (SSI).

11. A device for coding a signal, the device comprising:

means (10) for source coding the signal to obtain a coded data stream;

means (11, 12) for including source significance information (SSI) into the coded data stream, the source significance information (SSI) indicating desired protection rates (r) of respective parts (p) of the coded data stream.

12. A device (13) for coding a coded data stream, the coded data stream comprising respective groups of packets and a first header (SSI¹) present at a beginning of the coded data stream, the first header (SSI¹) being associated with a first packet of the group of packets and comprising source significance information including an offset (Δ

_ofs^l,1) indicating a start position of the associated first packet,

the device comprising;

means (13) for including a further header (h) in the coded data stream;

means (13) for replacing the first header (SSI¹) at the beginning of the coded data stream; and

means (13) for updating the offset (Δ

_ofs^l,1) in the first header (SSI¹).

13. A channel coder comprising:

means for receiving (14,15) a coded data stream, in which source significance information (SSI) has been included, the source significance information (SSI) indicating desired protection rates (r) of respective parts (p) of the coded data stream;

means for identifying (14) the source significance information (SSI) in the coded data stream; and

means for channel coding (15) respective parts of the coded bit-stream with respective protection rates (r) under control of the source significance information (SSI).

14. A channel decoder comprising:

means (17) for receiving a channel coded data stream, in which source significance information (SSI) has been incorporated, the source significance information (SSI) indicating protection rates (r_iⁿ) of respective parts (p_iⁿ) of the channel coded data stream;

means (18) for identifying the source significance information (SSI) in the channel coded data stream; and

means (19) for channel decoding respective parts of the coded bit-stream with respective protection rates (r_iⁿ) under control of the source significance information (SSI).

15. A coded data stream comprising source significance information (SSI) indicating desired protection rates (r_iⁿ) of respective parts (p_iⁿ) of the coded data stream.

16. A storage medium (3) on which a coded data stream as claimed in claim 15 has been stored.