Time slot position coding

• US 20070201514A1
• Filed: 08/30/2006
• Published: 08/30/2007
• Est. Priority Date: 08/30/2005
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Pang, Hee Suk, Lim, Jae Hyun, Jung, Yang Won, Kim, Dong Soo, Oh, Hyen
• Granted Patent: US 7,783,494 B2
• Time in Patent Office: Days
• US Class Current: 370/468
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04S 1/007 in which the audio signals are in digital form data reduction aspects thereof based on psychoacoustics G10L19/02
• CPC Class Codes: H04S 2420/03 Application of parametric coding in stereophonic audio systems
• CPC Class Codes: H04S 3/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30

Abstract

Spatial information associated with an audio signal is encoded into a bitstream, which can be transmitted to a decoder or recorded to a storage media. The bitstream can include different syntax related to time, frequency and spatial domains. In some embodiments, the bitstream includes one or more data structures (e.g., frames) that contain ordered sets of slots for which parameters can be applied. The data structures can be fixed or variable. The data structure can include position information that can be used by a decoder to identify the correct slot for which a given parameter set is applied. The slot position information can be encoded with either a fixed number of bits or a variable number of bits based on the data structure type.

Claims

1. A method of encoding an audio signal, the method comprising:

determining a number of time slots and a number of parameter sets, the parameter sets including one or more parameters;

generating information indicating a position of at least one time slot in an ordered set of time slots to which a parameter set is applied;

encoding the audio signal as a bitstream including a frame, the frame including the ordered set of time slots; and

inserting a variable number of bits in the bitstream that represent the position of the time slot in the ordered set of time slots, wherein the variable number of bits is determined by the time slot position.

2. A method of decoding an audio signal, comprising;

receiving a bitstream representing an audio signal, the bitstream having a frame;

determining a number of time slots and a number of parameter sets from the bitstream, the parameter sets including one or more parameters;

determining position information from the bitstream, the position information indicating a position of a time slot in an ordered set of time slots to which the parameter set is applied, where the ordered set of time slots is included in the frame; and

decoding the audio signal based on the number of time slots, the number of parameter sets and the position information,

wherein the position information is represented by a variable number of bits based on the time slot position.

3. The method of claim 2, wherein the variable number of bits is determined using the number of time slots.

4. The method of claim 2, further comprising:

if the number time slots to be decoded is equal to a number of parameter sets to be applied, not determining the position information of the time slot to which a parameter set is applied.

5. The method of claim 4, wherein if the number of the time slots is equal to or greater than 2ˆ

(n−

1) and less than 2ˆ

(n), the variable number of bits is determined as n bits.

6. The method of claim 4, wherein if the number of the time slots is greater than 2ˆ

(n−

1) and equal to or less than 2ˆ

(n), the variable number of bits is determined as n bits.

7. The method of claim 3, wherein the position information is represented as the sum of a previous value and a difference value, wherein the previous value indicates the position information of the time slot to which a first parameter set is applied and the difference value indicates the position information of the time slot to which a second parameter set is applied.

8. The method of claim 7, wherein the previous value is represented by a variable number of bits determined using at least one of the number of time slots and the number of parameter sets.

9. The method of claim 8, wherein the variable number of bits is determined using a difference between the number of time slots and the number of parameter sets.

10. The method of claim 7, wherein the difference value is represented by a variable number of bits determined using at least one of the number of time slots, the number of parameter sets and a position information of the time slot to which a previous parameter set is applied.

11. The method of claim 10, wherein the variable number of bits is determined using a difference between the number of time slots and at least one of the number of parameter sets and the position information of the time slot to which the previous parameter set is applied.

12. The method of claim 3, wherein if the number of parameter sets is N, the position information of the time slot to which the parameter set is applied, is represented as a combination using a formula as follows:

$\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>{\mathrm{numSlots}}^{i-1}·<br><br>{\mathrm{bsParamSlot}}_i,<br><br>0\le <br><br>{\mathrm{bsParamSlot}}_i<<br><br>\mathrm{numSlots},$

wherein numSlot and bsParamSlot_i indicate the number of time slots and the position information of the time slot to which an i^th parameter set is applied, respectively.

13. The method of claim 3, wherein if a plurality of the parameter sets exist, a plurality of the parameter sets are divided as a group and the position information of the time slot to which the parameter set is applied, is represented per the group.

14. The method of claim 12, wherein if the number of the parameter sets is (kN+L), the group is generated by binding N of the parameter sets together and is represented by M bits, and a last group is generated by binding L of the parameter sets together and is represented by P bits.

15. An apparatus for encoding an audio signal, comprising an encoder configured for:

determining a number of time slots and a number of parameter sets, the parameter sets including one or more parameters;

generating information indicating a position of at least one time slot in an ordered set of time slots to which a parameter set is applied;

encoding the audio signal as a bitstream including a frame, the frame including the ordered set of time slots; and

inserting a variable number of bits in the bitstream that represent the position of the time slot in the ordered set of time slots, wherein the variable number of bits is determined from the time slot position.

16. An apparatus for decoding an audio signal, comprising a decoder configured for:

receiving a bitstream representing an audio signal, the bitstream having a frame;

determining a number of time slots and a number of parameter sets from the bitstream, the parameter sets including one or more parameters;

determining position information from the bitstream, the position information indicating a position of a time slot in an ordered set of time slots included in the frame to which the parameter set is applied; and

decoding the audio signal based on the number of time slots, the number of parameter sets and the position information,

wherein the position information is represented by a variable number of bits based on the time slot position.

17. A data structure for inclusion in a bitstream representing an audio signal, the data structure comprising:

a first field including a number of time slots;

a second field including a number of parameter sets; and

a third field including position information for determining a position of a time slot to which a parameter set is applied, wherein the position information is represented by a variable number of bits based on the time slot position.

18. A computer-readable medium having stored thereon instructions which, when executed by a processor, causes the processor to perform the operations of:

receiving a bitstream representing an audio signal, the bitstream having a frame;

determining a number of time slots and a number of parameter sets from the bitstream, the parameter sets including one or more parameters;

determining position information from the bitstream, the position information indicating a position of a time slot in an ordered set of time slots included in the frame to which the parameter set is applied; and

decoding the audio signal based on the number of time slots, the number of parameter sets and the position information,

wherein the position information is represented by a variable number of bits based on the time slot position.

19. A system, comprising:

a processor;

a computer-readable medium coupled to the processor and including instructions, which when executed by a processor, causes the processor to perform the operations of;

receiving a bitstream representing an audio signal, the bitstream having a frame;

determining a number of time slots and a number of parameter sets from the bitstream, the parameter sets including one or more parameters;

determining position information from the bitstream, the position information indicating a position of a time slot in an ordered set of time slots included in the frame to which the parameter set is applied; and

decoding the audio signal based on the number of time slots, the number of parameter sets and the position information,

wherein the position information is represented by a variable number of bits based on the time slot position.

20. A system, comprising:

means for receiving a bitstream representing an audio signal, the bitstream having a frame;

means for determining a number of time slots and a number of parameter sets from the bitstream, the parameter sets including one or more parameters;

means for determining position information from the bitstream, the position information indicating a position of a time slot in an ordered set of time slots included in the frame to which the parameter set is applied; and

means for decoding the audio signal based on the number of time slots, the number of parameter sets and the position information,

wherein the position information is represented by a variable number of bits based on the time slot position.