Coding independent frames of ambient higher-order ambisonic coefficients
In general, techniques are described for coding an ambient higher order ambisonic coefficient. An audio decoding device comprising a memory and a processor may perform the techniques. The memory may store a first frame of a bitstream and a second frame of the bitstream. The processor may obtain, from the first frame, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to the second frame. The processor may further obtain, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for first channel side information data of a transport channel. The prediction information may be used to decode the first channel side information data of the transport channel with reference to second channel side information data of the transport channel.
1. A method of decoding a bitstream including a transport channel specifying one or more bits indicative of encoded higher-order ambisonic audio data, the method comprising:
obtaining, from a first frame of the bitstream including first channel side information data of the transport channel, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to a second frame of the bitstream including second channel side information data of the transport channel; and
obtaining, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for the first channel side information data of the transport channel, the prediction information used to decode the first channel side information data of the transport channel with reference to the second channel side information data of the transport channel.
2. The method of claim 1 , wherein the one or more bits indicative of the encoded higher-order ambisonic audio data comprises one or more bits indicative of a coded element of a vector representative of an orthogonal spatial axis in a spherical harmonics domain.
3. The method of claim 2 , wherein the vector comprises a V-vector decomposed from the higher-order ambisonic audio data.
4. The method of claim 2 , wherein the prediction information comprises one or more bits indicative of whether a value of the coded element of the vector specified in the first channel side information data is predicted from a value of the coded element of the vector associated with the second channel side information data.
5. The method of claim 2 , further comprising, in response to the one or more bits indicating that the first frame is an independent frame, setting the prediction information to indicate that the value of the coded element of the vector associated with the first channel side information data is not predicted with reference to the value of the vector associated with the second channel side information data.
6. The method of claim 1 , wherein the additional reference information comprises one or more bits indicative of a quantization mode used to encode the higher-order ambisonic audio data specified by the first channel side information data.
7. The method of claim 6 , wherein the one or more bits indicative of the quantization mode comprise one or more bits indicative of a non-Huffman coded, scalar quantization mode.
8. The method of claim 6 , wherein the one or more bits indicative of the quantization mode comprise one or more bits indicative of Huffman coded, scalar quantization mode.
9. The method of claim 6 , wherein the one or more bits indicative of the quantization mode comprise one or more bits indicative of a vector quantization mode.
10. The method of claim 1 , wherein the additional reference information comprises Huffman codebook information used to encode the higher-order ambisonic data.
11. The method of claim 1 , wherein the additional reference information comprises vector quantization codebook information used to encode the higher-order ambisonic data.
12. The method of claim 1 , wherein the additional reference information comprises a number of vectors used when performing vector quantization with respect to the higher-order ambisonic data.
13. The method of claim 1 , further comprising, in response to the one or more bits indicating that the first frame is not an independent frame:
obtaining, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data; and
when the combination of the most significant bit and the second most significant bit equals zero, setting the quantization mode used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the quantization mode used to encode the higher-order ambisonic data specified in the second channel side information data.
14. The method of claim 1 , further comprising, in response to the one or more bits indicating that the first frame is not an independent frame obtaining, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data,
wherein obtaining the prediction information comprises, when the combination of the most significant bit and the second most significant bit equals zero, setting the prediction information used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the prediction mode used to encode the higher-order ambisonic data specified in the second channel side information data.
15. The method of claim 1 , further comprising, in response to the one or more bits indicating that the first frame is not an independent frame:
obtaining, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data; and
when the combination of the most significant bit and the second most significant bit equals zero, setting the Huffman codebook information used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the quantization mode used to encode the higher-order ambisonic data specified in the second channel side information data.
16. The method of claim 1 , further comprising, in response to the one or more bits indicating that the first frame is not an independent frame:
obtaining, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data; and
when the combination of the most significant bit and the second most significant bit equals zero, setting the vector quantization codebook information used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the quantization mode used to encode the higher-order ambisonic data specified in the second channel side information data.
17. The method of claim 1 , wherein the second frame temporally precedes the first frame.
18. An audio decoding device configured to decode a bitstream including a transport channel specifying one or more bits indicative of encoded higher-order ambisonic audio data, the audio decoding device comprising:
a memory configured to store a first frame of the bitstream including first channel side information data of the transport channel and a second frame of the bitstream including second channel side information data of the transport channel; and
one or more processors configured to obtain, from the first frame, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to the second frame, and obtain, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for the first channel side information data of the transport channel, the prediction information used to decode the first channel side information data of the transport channel with reference to the second channel side information data of the transport channel.
19. The audio decoding device of claim 18 , wherein the one or more bits indicative of the encoded higher-order ambisonic audio data comprises one or more bits indicative of a coded element of a vector representative of an orthogonal spatial axis in a spherical harmonics domain.
20. The audio decoding device of claim 19 , wherein the vector comprises a V-vector decomposed from the higher-order ambisonic audio data.
21. The audio decoding device of claim 19 , wherein the prediction information comprises one or more bits indicative of whether a value of the coded element of the vector specified in the first channel side information data is predicted from a value of the coded element of the vector associated with the second channel side information data.
22. The audio decoding device of claim 19 , wherein the one or more processors are further configured to, in response to the one or more bits indicating that the first frame is an independent frame, set the prediction information to indicate that the value of the coded element of the vector associated with the first channel side information data is not predicted with reference to the value of the vector associated with the second channel side information data.
23. The audio decoding device of claim 18 , wherein the additional reference information comprises one or more bits indicative of a quantization mode used to encode the higher-order ambisonic audio data specified by the first channel side information data.
24. The audio decoding device of claim 23 , wherein the one or more bits indicative of the quantization mode comprise one or more bits indicative of a non-Huffman coded, scalar quantization mode.
25. The audio decoding device of claim 23 , wherein the one or more bits indicative of the quantization mode comprise one or more bits indicative of Huffman coded, scalar quantization mode.
26. The audio decoding device of claim 23 , wherein the one or more bits indicative of the quantization mode comprise one or more bits indicative of a vector quantization mode.
27. The audio decoding device of claim 18 , wherein the additional reference information comprises Huffman codebook information used to encode the higher-order ambisonic data.
28. The audio decoding device of claim 18 , wherein the additional reference information comprises vector quantization codebook information used to encode the higher-order ambisonic data.
29. The audio decoding device of claim 18 , wherein the additional reference information comprises a number of vectors used when performing vector quantization with respect to the higher-order ambisonic data.
30. The audio decoding device of claim 18 , wherein the one or more processors are further configured to, in response to the one or more bits indicating that the first frame is not an independent frame, obtain, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data, and when the combination of the most significant bit and the second most significant bit equals zero, set the quantization mode used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the quantization mode used to encode the higher-order ambisonic data specified in the second channel side information data.
31. The audio decoding device of claim 18 , wherein the one or more processors are further configured to, in response to the one or more bits indicating that the first frame is not an independent frame, obtain, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data, and when the combination of the most significant bit and the second most significant bit equals zero, set the prediction information used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the prediction mode used to encode the higher-order ambisonic data specified in the second channel side information data.
32. The audio decoding device of claim 18 , wherein the one or more processors are further configured to, in response to the one or more bits indicating that the first frame is not an independent frame, obtain, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data, and when the combination of the most significant bit and the second most significant bit equals zero, set the Huffman codebook information used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the quantization mode used to encode the higher-order ambisonic data specified in the second channel side information data.
33. The audio decoding device of claim 18 , wherein the one or more processors are further configured to, in response to the one or more bits indicating that the first frame is not an independent frame obtain, from the first channel side information data of the transport channel, a most significant bit and a second most significant bit indicative of a quantization mode used to encode the higher-order ambisonic audio data, and when the combination of the most significant bit and the second most significant bit equals zero, set the vector quantization codebook information used to encode the higher-order ambisonic data specified in the first channel side information data as equal to the quantization mode used to encode the higher-order ambisonic data specified in the second channel side information data.
34. The audio decoding device of claim 18 , wherein the second frame temporally precedes the first frame.
35. An audio decoding device configured to decode a bitstream representative of encoded higher-order ambisonic audio data, the audio decoding device comprising:
means for storing the bitstream that includes a first frame comprising a vector representative of an orthogonal spatial axis in a spherical harmonics domain; and
means for extracting, from a first frame of the bitstream, one or more bits indicative of whether the first frame is an independent frame that includes vector quantization information to enable the vector to be decoded without reference to a second frame of the bitstream.
36. The audio decoding device of claim 35 , further comprises means for extracting, when the one or more bits indicate that the first frame is an independent frame, the vector quantization information from the bitstream.
37. The audio decoding device of claim 36 , wherein the vector quantization information does not include prediction information indicating whether predicted vector quantization was used to quantize the vector.
38. The audio decoding device of claim 36 , further comprising means for setting, when the one or more bits indicate that the first frame is an independent frame, prediction information to indicate that predicted vector dequantization is not performed with respect to the vector.
39. The audio decoding device of claim 35 , further comprising means for extracting, when the one or more bits indicate that the first frame is not an independent frame, prediction information from the vector quantization information, the prediction information indicating whether predicted vector quantization was used to quantize the vector.
40. The audio decoding device of claim 35 , further comprising:
means for extracting, when the one or more bits indicate that the first frame is not an independent frame, prediction information from the vector quantization information, the prediction information indicating whether predicted vector quantization was used to quantize the vector; and
means for performing, when the prediction information indicates that predicted vector quantization was used to quantize the vector, predicted vector dequantization with respect to the vector.
41. The audio decoding device of claim 35 , further comprising means for extracting codebook information from the vector quantization information, the codebook information indicating a codebook used to vector quantize the vector.
42. The audio decoding device of claim 35 , further comprising:
means for extracting codebook information from the vector quantization information, the codebook information indicating a codebook used to vector quantize the vector; and
means for performing vector quantization with respect to the vector using the codebook indicated by the codebook information.
43. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to:
obtain, from a first frame of a bitstream including first channel side information data of a transport channel, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to a second frame of the bitstream including second channel side information data of the transport channel, the bitstream representative of encoded higher-order ambisonic audio data; and
obtain, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for the first channel side information data of the transport channel, the prediction information used to decode the first channel side information data of the transport channel with reference to the second channel side information data of the transport channel.
44. A method of encoding higher-order ambient coefficients to obtain a bitstream including a transport channel specifying one or more bits indicative of the encoded higher-order ambisonic audio data, the method comprising:
specifying, in a first frame of the bitstream including first channel side information data of the transport channel, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to a second frame of the bitstream including second channel side information data of the transport channel; and
specifying, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for the first channel side information data of the transport channel, the prediction information used to decode the first channel side information data of the transport channel with reference to the second channel side information data of the transport channel.
45. The method of claim 44 , wherein the one or more bits indicative of the encoded higher-order ambisonic audio data comprises one or more bits indicative of a coded element of a vector representative of an orthogonal spatial axis in a spherical harmonics domain.
46. The method of claim 45 , wherein the vector comprises a V-vector decomposed from the higher-order ambisonic audio data.
47. The method of claim 45 , wherein the prediction information comprises one or more bits indicative of whether a value of the coded element of the vector specified in the first channel side information data is predicted from a value of the coded element of the vector specified in the second channel side information data.
48. The method of claim 45 , further comprising, in response to the one or more bits indicating that the first frame is an independent frame, setting the value of the coded element of the vector of the first channel side information data is not predicted with reference to the value of the coded element of the vector of the second channel side information data.
49. The method of claim 44 , wherein the additional reference information comprises one or more bits indicative of a quantization mode used to encode the higher-order ambisonic audio data specified by the first channel side information data, the one or more bits indicative of the quantization mode comprise one of 1) one or more bits indicative of a non-Huffman coded, scalar quantization mode, 2) one or more bits indicative of Huffman coded, scalar quantization mode, or 3) one or more bits indicative of a vector quantization mode.
50. The method of claim 44 , wherein the additional reference information comprises one of 1) Huffman codebook information used to encode the higher-order ambisonic data or 2) vector quantization information used to encode the higher-order ambisonic data.
51. The method of claim 44 , wherein the additional reference information comprises a number of vectors used when performing vector quantization with respect to the higher-order ambisonic data.
52. An audio encoding device configured to encode higher-order ambient coefficients to obtain a bitstream including a transport channel specifying one or more bits indicative of the encoded higher-order ambisonic audio data, the audio encoding device comprising:
a memory configured to store the bitstream; and
one or more processors configured to specify, in a first frame of the bitstream including first channel side information data of the transport channel, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to a second frame of the bitstream including second channel side information data of the transport channel, and specify, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for the first channel side information data of the transport channel, the prediction information used to decode the first channel side information data of the transport channel with reference to the second channel side information data of the transport channel.
53. The audio encoding device of claim 52 , wherein the one or more bits indicative of the encoded higher-order ambisonic audio data comprises one or more bits indicative of a coded element of a vector representative of an orthogonal spatial axis in a spherical harmonics domain.
54. The audio encoding device of claim 53 , wherein the vector comprises a V-vector decomposed from the higher-order ambisonic audio data.
55. The audio encoding device of claim 53 , wherein the prediction information comprises one or more bits indicative of whether a value of the coded element of the vector specified in the first channel side information data is predicted from a value of the coded element of the vector specified in the second channel side information data.
56. The audio encoding device of claim 53 , wherein the one or more processors are further configured to, in response to the one or more bits indicating that the first frame is an independent frame, set the value of the coded element of the vector of the first channel side information data is not predicted with reference to the value of the coded element of the vector of the second channel side information data.
57. The audio encoding device of claim 52 , wherein the additional reference information comprises one or more bits indicative of a quantization mode used to encode the higher-order ambisonic audio data specified by the first channel side information data, the one or more bits indicative of the quantization mode comprise one of 1) one or more bits indicative of a non-Huffman coded, scalar quantization mode, 2) one or more bits indicative of Huffman coded, scalar quantization mode, or 3) one or more bits indicative of a vector quantization mode.
58. The audio encoding device of claim 52 , wherein the additional reference information comprises one of 1) Huffman codebook information used to encode the higher-order ambisonic data or 2) vector quantization information used to encode the higher-order ambisonic data.
59. The method of claim 52 , wherein the additional reference information comprises a number of vectors used when performing vector quantization with respect to the higher-order ambisonic data.
60. An audio encoding device configured to encode higher-order ambient audio data to obtain a bitstream, the audio encoding device comprising:
means for storing the bitstream that includes a first frame comprising a vector representative of an orthogonal spatial axis in a spherical harmonics domain; and
means for specifying, in the first frame of the bitstream, one or more bits indicative of whether the first frame is an independent frame that includes vector quantization information to enable the vector to be decoded without reference to a second frame of the bitstream.
61. The audio encoding device of claim 60 , further comprises means for specifying, when the one or more bits indicate that the first frame is an independent frame, the vector quantization information from the bitstream.
62. The audio encoding device of claim 61 , wherein the vector quantization information does not include prediction information indicating whether predicted vector quantization was used to quantize vector.
63. The audio encoding device of claim 61 , further comprising means for setting, when the one or more bits indicate that the first frame is an independent frame, prediction information to indicate that predicted vector dequantization is not performed with respect to the vector.
64. The audio encoding device of claim 60 , further comprising means for setting, when the one or more bits indicate that the first frame is not an independent frame, prediction information for the vector quantization information, the prediction information indicating whether predicted vector quantization was used to quantize the vector.
65. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause one or more processors to:
specify, in a first frame of a bitstream including first channel side information data of a transport channel, one or more bits indicative of whether the first frame is an independent frame that includes additional reference information to enable the first frame to be decoded without reference to a second frame of the bitstream including second channel side information data of the transport channel, the bitstream representative of encoded higher-order ambisonic audio data; and
specify, in response to the one or more bits indicating that the first frame is not an independent frame, prediction information for the first channel side information data of the transport channel, the prediction information used to decode the first channel side information data of the transport channel with reference to the second channel side information data of the transport channel.