Method and apparatus for coding or decoding subband configuration data for subband groups

• US 10,102,864 B2
• Filed: 08/19/2015
• Issued: 10/16/2018
• Est. Priority Date: 09/02/2014
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Keiler, Florian, Kordon, Sven, Krueger, Alexander
• Primary Examiner(s): Cyr, Leonard Saint
• Application Number:
  US15/508,444
• Publication Number:
  US 20170243592A1
• Time in Patent Office: 1,154 Days
• Field of Search: 704500-504
• CPC Class Codes: G10L 19/002 Dynamic bit allocation for perceptual audio coders G10L19/032
• CPC Class Codes: G10L 19/0204 using subband decomposition

Abstract

For an efficient encoding of subband configuration data the first, penultimate and last subband groups are treated differently than the other subband groups. Further, subband group bandwidth difference values are used in the encoding. The number of subband groups N_SB is coded using a fixed number of bits representing N_SB−1. The bandwidth value B_SB[1] of the first subband group is coded using a unary code representing B_SB[1]−1. No bandwidth value B_SB[g] is coded for the last subband g=N_SB. For subband groups g=2, . . . , N_SB−2 bandwidth difference values ΔB_SB[g]=B_SB[g]−B_SB[g−1] are coded using a unary code, and the bandwidth difference value ΔB_SB[N_SB−1] for subband group g=N_SB−1 is coded using a fixed number of bits.

Claims

1. A non-transitory medium having instructions stored thereon for controlling one or more processors to perform a method for coding audio subband configuration data (N_SB, G₁ . . . G_NSB) for audio subband groups (g) for one or more frames of an audio signal, said method comprising:

coding a number of audio subband groups N_SB with a fixed number of bits (N_b,SB) representing N_SB−

1;

coding, based on a determination that N_SB>

1, for a first audio subband group g=1 a bandwidth value B_SB[1] with a unary code representing B_SB[1]−

1;

coding, based on a determination that N_SB=3, for audio subband group g=2 a bandwidth difference value Δ

B_SB[2]=B_SB[2]−

B_SB[1] with a fixed number of bits (N_b,lastDiff);

coding, based on a determination that N_SB>

3, for audio subband groups g=2, . . . , N_SB−

2 a corresponding number of bandwidth difference values Δ

B_SB[g]=B_SB[g]−

B_SB[g−

1] with a unary code, and coding for audio subband group g=N_SB−

1 a bandwidth difference value Δ

B_SB[N_SB−

1]=B_SB[N_SB−

1]−

B_SB[N_SB−

2] with a fixed number of bits (N_b,lastDiff),

wherein a bandwidth value for an audio subband group is based on a number of adjacent original audio subbands,

and wherein no corresponding value is included in the coded audio subband configuration data based on a determination that audio subband g=N_SB.

2. A non-transitory medium according to claim 1, wherein an audio subband configuration data block (s_SBconfig) includes a configuration value (configIdx) that determines whether:

a first combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or a different second combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or further combinations of number of audio subband groups and related audio subband group widths represent said audio subband configuration data,

or audio subband configuration data are coded according to the method of claim 1,

wherein no audio subband configuration data is generated based on a determination that N_SB=0.

3. A non-transitory storage medium that contains or stores, or has recorded on it, a digital compressed audio signal that contains audio subband configuration data encoded according to the method of claim 1.

4. A non-transitory storage medium that contains or stores, or has recorded on it, a digital compressed audio signal that contains multiple sets of different audio subband configuration data encoded according to the method of claim 1.

8. A non-transitory medium according to claim 7, wherein the decoding is based on an audio subband configuration data block (s_SBconfig) that includes a configuration value (configIdx) that indicates whether:

a first combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or a different second combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or further combinations of number of audio subband groups and related audio subband group widths represent said audio subband configuration data,

or audio subband configuration data were coded according to the method of claim 1.

11. An apparatus according to claim 10, wherein the decoder is further configured to include an audio subband configuration data block (s_SBconfig) that includes a configuration value (configIdx) that indicates whether:

a first combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or a second predefined combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or further combinations of number of audio subband groups and related audio subband group widths represent said audio subband configuration data,

or audio subband configuration data were coded according to the method of claim 1.

5. An apparatus for coding audio subband configuration data (N_SB, G₁ . . . G_NSB) for audio subband groups (g) said apparatus comprising:

at least one or more processors;

an encoder configured to code a number of audio subband groups N_SB with a fixed number of bits (N_b,SB) representing N_SB−

1, the encoder further configured to;

code, based on a determination that N_SB>

1, for a first audio subband group g=1 a bandwidth value B_SB[1] with a unary code representing B_SB[1]−

1;

code, based on a determination that N_SB=3, for audio subband group g=2 a bandwidth difference value Δ

B_SB [2]=B_SB[2]−

B_SB[1] with a fixed number of bits (N_b,lastDiff);

code, based on a determination that N_SB>

3, for audio subband groups g=2, . . . , N_SB−

2 a corresponding number of bandwidth difference values Δ

B_SB[g]=B_SB[g]−

B_SB[g−

1] with a unary code, and coding for audio subband group g=N_SB−

1 a bandwidth difference value Δ

B_SB[N_SB−

1]=B_SB[N_SB−

1]−

B_SB[N_SB−

2] with a fixed number of bits (N_b,lastDiff),

wherein a bandwidth value for an audio subband group is based on a number of adjacent original audio subbands,

and wherein no corresponding value is included in the coded audio subband configuration data based on a determination that audio subband g=N_SB.

6. An apparatus according to claim 5, wherein the encoder is further configured to include an audio subband configuration data block (s_SBconfig) includes a configuration value (configIdx) that determines whether:

a first combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or a different second combination of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or further combinations of number of audio subband groups and related audio subband group widths represents said audio subband configuration data,

or audio subband configuration data are coded according to the encoder configuration of claim 5, wherein no audio subband configuration data is generated based on a determination that N_SB=0.

7. A non-transitory medium having instructions stored thereon for controlling one or more processors to perform a method for decoding coded audio subband configuration data (s_SBconfig) for audio subband groups (g) valid for one or more frames of a coded audio signal, the method comprising:

determining a number of audio subband groups N_SB based on a decoded version of a coded number of audio subband groups;

determining for a first audio subband group g=1 a bandwidth value B_SB[1] based on a decoded version of the corresponding coded bandwidth value;

decoding a group g,

wherein, based on a determination that N_SB=3, for an audio subband group g=2 decoding from a coded version of bandwidth difference value Δ

B_SB[2] a bandwidth value B_SB[2]=Δ

B_SB[2]+B_SB[1], and

wherein,

based on a determination that N_SB>

3, for audio subband groups g=2, . . . , N_SB−

2 decoding from a coded version of bandwidth difference values Δ

B_SB[g] bandwidth values B_SB[g]=Δ

B_SB[g]+B_SB[g−

1], and decoding for audio subband group g=N_SB−

1 from a coded version of bandwidth difference value Δ

B_SB[N_SB−

1] a bandwidth value B_SB[N_SB−

1]=Δ

B_SB[N_SB−

1]+B_SB[N_SB−

2]; and

determining a bandwidth value B_SB[N_SB] for subband g=N_SB by subtracting the bandwidths B_SB[1] to B_SB[N_SB−

1] from N_FB,

wherein a bandwidth value for an audio subband group is based on a number of adjacent original audio subbands.

9. The non-transitory medium of claim 7, wherein the number of audio subband groups N_SB is determined by adding ‘

1’

to the decoded version of the coded number of audio subband groups.

10. An apparatus for decoding coded audio subband configuration data (s_SBconfig) for audio subband groups (g) valid for one or more frames of a coded audio signal, the apparatus comprising:

at least one or more processors;

a decoder configured to determine a number of audio subband groups N_SB based on a decoded version of coded number of audio subband groups, the decoder further configured to determine, for a first audio subband group g=1 a bandwidth value B_SB[1] based on a decoded version of the corresponding coded bandwidth value,

wherein

based on a determination that N_SB=3, the decoder is further configured to decode, for audio subband group g=2 from the coded version of bandwidth difference value Δ

B_SB[2] a bandwidth value B_SB[2]=Δ

B_SB[2]+B_SB[1], and

wherein, based on a determination that N_SB>

3, for said first audio subband group g=1, the decoder is further configured to decode, for audio subband groups g=2, . . . , N_SB−

2 from the coded version of bandwidth difference values Δ

B_SB[g] bandwidth values B_SB[g]=Δ

B_SB[g]+B_SB[g−

1], and to decode for audio subband group g=N_SB−

1 from the coded version of bandwidth difference value Δ

B_SB[N_SB−

1] a bandwidth value B_SB[N_SB−

1]=Δ

B_SB[N_SB−

1]+B_SB[N_SB−

2],

wherein the decoder is further configured to determine a bandwidth value B_SB[N_SB] for audio subband g=N_SB by subtracting the bandwidths B_SB[1] to B_SB[N_SB−

1] from N_FB, and

wherein a bandwidth value for an audio subband group is based on a number of adjacent original audio subbands.

12. The apparatus of claim 10, wherein decoder is configured to determine the number of audio subband groups N_SB by adding ‘

1’

to the decoded version of the coded number of audio subband groups.