Decoding of an encoded wideband digital audio signal in a transmission system for transmitting and receiving such signal

• US 7,209,565 B2
• Filed: 12/23/2003
• Issued: 04/24/2007
• Est. Priority Date: 06/02/1989
• Status: Expired due to Fees

• Current Assignee: TDF SAS (Fluor Corporation)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Lokhoff, Gerardus C. P., Stoll, Gunther Josef, Dehery, Yves-Francois
• Primary Examiner(s): MCFADDEN, SUSAN IRIS
• Application Number:
  US10/745,215
• Publication Number:
  US 20040138895A1
• Time in Patent Office: 1,218 Days
• Field of Search: None
• US Class Current: 381/22
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G11B 20/00007 Time or data compression or expansion audio compression based on psychoacoustics G10L19/00; data processing for reproducing audio data at different playback speeds G10L21/04; video compression H04N19/00; data compression per se H03M7/30
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 20/12 Formatting, e.g. arrangement of data block or words on the record carriers within interface between computers and data recorders G06F3/06
• CPC Class Codes: G11B 2020/10592 specifically adapted for recording or reproducing multichannel signals
• CPC Class Codes: G11B 2020/10601 surround sound signal
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 2220/913 Digital audio tape [DAT] format
• CPC Class Codes: G11B 2220/93 Longitudinal format, wherein tracks are in the direction of the tape, read with a static head, e.g. DCC
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: H04B 1/665 using psychoacoustic properties of the ear, e.g. masking effect
• CPC Class Codes: H04B 1/667 using a division in frequency subbands for TV signals H04N19/63
• CPC Class Codes: H04H 20/88 Stereophonic broadcast systems multiplex system in general H04J
• CPC Class Codes: H04H 40/27 specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95

Abstract

Reproduction accuracy of a digital signal, representing for example stereo audio signals, is improved by transmitting sample data which have been encoded to form transmission signals. The transmission signals are arranged in consecutive frames, each frame including a plurality of information packets, and each information packet including N bits. The number of information packets in a frame is determined by the ratio of the product of the transmission bit-rate and the number of samples represented in the frame, to the product of the number of bits in a packet and the sampling frequency. The transmission signals are recorded in a record carrier, or are transmitted in real time. In a digital stereo audio signal embodiment, the samples may be sub-band encoded or transform encoded. The transmission signal may include an indicator signal indicating a combination of certain samples, or scale factor signals for specific components of the sampled signal.

Claims

1. A decoder for decoding an encoded digital signal, wherein the encoded digital signal represents a wideband digital audio signal having a sampling frequency F_s, and comprises consecutive frames, each frame comprising a plurality of information packets, each information packet comprising N bits, N being larger than 1, a frame comprising at least a first frame portion including synchronization information, and wherein the decoder comprises:

an input for receiving the encoded digital signal;

means for converting the encoded digital signal into a replica of the wideband audio digital signal; and

an output for supplying the replica of the wideband digital audio signal,

wherein said means for converting converts a signal having a number of information packets in one frame, determined according to the formula P=BR/N×

n_s/F_s, where BR is the bit-rate of the encoded digital signal and n_s is the number of samples of the wideband digital audio signal having corresponding information in the encoded digital signal included in one frame of the encoded digital signal, and if P is an integer, the number of information packets in one frame is P, and if P is not an integer, the number of information packets in a number v of the frames is P′

, where P′

is the highest integer having a value less than P, and the number of information packets in a number w of the other frames is equal to P′

+1, the numbers v and w being selected such that the average frame rate of the encoded digital signal is substantially equal to F_s/n_s.

2. The decoder as claimed in claim 1, wherein the decoder further comprises:

retrieval means for retrieving further information relating to the number of information packets in the frame from the first frame portion.

3. The decoder as claimed in claim 1, wherein the decoder further comprises:

means for retrieving a padding bit from the frame indicating a relative number of information packets in the frame compared to another frame.

4. The decoder as claimed in claim 1, wherein the decoder further comprises:

means for retrieving system information from the first frame portion in said frame.

5. The decoder as claimed in claim 4, wherein the decoder further comprises:

means for retrieving, from the system information in said first frame portion, information relating to the bit-rate BR.

6. The decoder as claimed in claim 4, wherein the decoder further comprises:

means for retrieving, from said system information, information relating to the sampling frequency F_s.

7. The decoder as claimed in claim 4, wherein the decoder further comprises:

means for retrieving, from said system information, information identifying said frame as having one information packet more than other frames.

8. The decoder as claimed in claim 7, wherein said identifying information is in the form of a padding bit, said bit being ‘

1’

if said frame has one information packet more than other frames.

9. The decoder as claimed in claim 7, wherein the decoder further comprises:

means for retrieving a padding bit, said bit being ‘

1’

if said frame has one information packet more than other frames.

10. The decoder as claimed in claim 1, wherein said first frame portion comprises a padding bit, said bit being ‘

1’

if said frame has one information packet more than other frames.

11. The decoder as claimed in claim 1, wherein said decoder further comprises:

means for retrieving a padding bit, said bit being ‘

1’

if said frame has one information packet more than other frames.

12. The decoder as claimed in claim 4, wherein said decoder further comprises:

retrieval means for retrieving system information identifying said encoded digital signal as a mono audio signal, a bilingual signal, or an intensity stereo audio signal.

13. The decoder as claimed in any one of claims 1 to 9, wherein the decoder further comprises:

means for retrieving, from the frame, at least one sample representative of at least one quantized sub-signal of said wideband digital audio signal.

14. The decoder as claimed in claim 13, wherein the decoder further comprises:

a dequantizing unit for dequantizing said at least one quantized subsignal; and

a subband synthesis filter unit for converting said dequantized at least one quantized sub-signal into the replica of the wideband digital audio signal.

15. The decoder as claimed in claim 1, wherein the decoder further comprises:

means for retrieving scale factor information from said frame.

16. The decoder as claimed in claim 13, wherein said means for retrieving from the frame at least one sample representative of at least one quantized sub-signal further comprises means for retrieving bit allocation information in the form of at least one 4-bit word representing the number of bits with which said at least one sample of said at least one quantized sub-signal are represented.

17. The decoder as claimed in claim 15, wherein the decoder further comprises:

means for retrieving at least one 6-bit word from the scale factor information representing a scale factor for at least one quantized sub-signal of said wideband digital audio signal.

18. The decoder as claimed in claim 16, wherein the decoder further comprises:

means for inhibiting retrieval of samples for a sub-signal when the 4-bit word ‘

0000’

is detected.

19. The decoder as claimed in claim 16, wherein the decoder further comprises:

means for inhibiting retrieval of a scale factor for a sub-signal when the 4-bit word ‘

0000’

is detected.

20. The decoder as claimed in claim 1, wherein F_s=48 kHz.

21. The decoder as claimed in claim 1, wherein F_s=44.1 kHz.

22. The decoder as claimed in claim 1, wherein N=32.

23. The decoder as claimed in claim 1, wherein n_s=384.

24. The decoder as claimed in claim 1, wherein BR=384.

25. A receiver for receiving an encoded digital signal and for converting the encoded digital signal into a wideband digital audio signal, the receiver comprising a decoder for decoding the encoded digital signal, the encoded digital signal representing a wideband digital signal having a sampling frequency F_s, and comprising consecutive frames, each frame comprising a plurality of information packets, each information packet comprising N bits, N being larger than 1, a frame comprising at least a first frame portion including synchronization information, the decoder comprising:

an input for receiving the encoded digital signal; and

means for converting the encoded digital signal into a replica of the wideband digital audio signal, and an output for supplying the replica of the wideband digital audio signal, wherein said means for converting converts a signal having a number of information packets in one frame determined according to the formula P=BR/N×

n_s/F_s, where BR is the bit-rate of the encoded digital signal and n_s is the number of samples of the wideband digital audio signal having corresponding information in the encoded digital signal included in one frame of the encoded digital signal, and if P is an integer, the number of information packets in one frame is P, and if P is not an integer, the number of information packets in a number v of the frames is P′

, where P′

is the highest integer whose value is less than P, and the number of information packets in a number w of the other frames is equal to P′

+1, the numbers v and w being selected such that the average frame rate of the encoded digital signal is substantially equal to F_s/n_s.

26. The receiver as claimed in claim 25, wherein said receiver further comprises:

means for reproducing said wideband digital audio signal from a record carrier.

27. The receiver as claimed in claim 25, wherein said receiver further comprises:

means for reproducing said wideband digital audio signal from a memory.

28. The receiver as claimed in claim 25, wherein said receiver further comprises:

means for reproducing said wideband digital audio signal from a magnetic media.

29. The receiver as claimed in claim 25, wherein said receiver further comprises:

means for reproducing said wideband digital audio signal from a transmission stream.

30. The receiver as claimed in claim 25, wherein said receiver further comprises:

means for generating a perceptible audio signal from said replica of the wideband digital audio signal.

31. A method for decoding an encoded digital signal, the encoded digital signal representing a wideband digital audio signal having a sampling frequency F_s, and comprising consecutive frames, each frame comprising a plurality of information packets, each information packet comprising N bits, N being larger than 1, a frame comprising at least a first frame portion including synchronization information, the method comprising the steps:

receiving the encoded digital signal;

converting the encoded digital signal into a replica of the wideband audio digital signal, wherein said encoded digital signal has a number of information packets in one frame determined according to the formula P=BR/N×

n_s/F_s where BR is the bit-rate of the encoded digital signal and n_s is the number of samples of the wideband digital audio signal whose corresponding information in the encoded digital signal is included in one frame of the encoded digital signal, and if P is an integer, the number of information packets in one frame is P, and if P is not an integer, the number of information packets in a number v of the frames is P′

, where P′

is the highest integer whose value is less than P, and the number of information packets in a number w of the other frames is equal to P′

+1, the numbers v and w being selected such that the average frame rate of the encoded digital signal is substantially equal to F_s/n_s; and

outputting the replica of the wideband digital audio signal.

32. The method as claimed in claim 31, wherein the method further comprises the step:

retrieving information from the frame related to the number of information packets in the frame.

33. The method as claimed in claim 31, wherein the method further comprises the step:

retrieving a padding bit from the frame indicating a relative number of information packets in the frame compared to another frame.

34. The method as claimed in claim 31, wherein the method further comprises the step:

retrieving system information from the frame.

35. The method as claimed in claim 34, wherein the step of retrieving system information from the frame comprises the sub-step:

retrieving information indicating whether a frame has one information packet more than another frame.

36. The method as claimed in claim 35, wherein the step of retrieving system information from the frame further comprises the sub-step:

retrieving a one bit padding indicator indicating whether a frame has one information packet more than another frame.

37. The method as claimed in any one of claims 31 to 36, wherein the method further comprises the step:

retrieving from the frame at least one sample representative of at least one quantized sub-signal of said wideband digital audio signal.

38. The method as claimed in claim 37, wherein the method further comprises the steps:

dequantizing said at least one quantized sub-signal; and

converting said at least one quantized sub-signal into the replica of the wideband digital audio signal using sub-band synthesis filtering.

39. The method as claimed in claim 31, wherein the method further comprises the step:

retrieving the encoded digital information signal from a storage medium.

40. A decoder for decoding an encoded digital signal, the encoded digital signal representing a wideband digital audio signal having a sampling frequency F_s, and comprising consecutive frames, each frame comprising a plurality of information packets, each information packet comprising N bits, N being larger than 1, a frame comprising at least a first frame portion including synchronization information, the decoder comprising:

an input for receiving the encoded digital signal;

a converter comprising a processor for converting the encoded digital signal into a replica of the wideband audio digital signal; and

an output for supplying the replica of the wideband digital audio signal, characterized in that said converter converts a signal having a number of information packets in one frame determined according to the formula P=BR/N×

n_s/F_s where BR is the bit-rate of the encoded digital signal and n_s is the number of samples of the wideband digital audio signal having corresponding information in the encoded digital signal included in one frame of the encoded digital signal, and if P is an integer, the number of information packets in one frame is P, and if P is not an integer, the number of information packets in a number v of the frames is P′

, where P′

is the highest integer having a value less than P, and the number of information packets in a number w of the other frames is equal to P′

+1, the numbers v and w being selected such that the average frame rate of the encoded digital signal is substantially equal to F_s/n_s.

41. A decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving further information relating to the number of information packets in the frame from the first frame portion in said frame.

42. A decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing further information relating to the number of information packets in the frame.

43. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving a padding bit from the frame indicating a relative number of information packets in the frame compared to another frame.

44. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing a padding bit from the frame indicating a relative number of information packets in the frame compared to another frame.

45. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing information representative of the state of a padding bit from the frame indicating a relative number of information packets in the frame compared to another frame.

46. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting further information relating to the number of information packets in the frame from the first frame portion in said frame.

47. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving system information from said frame.

48. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing system information from said frame.

49. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting system information from said frame.

50. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving information relating to the bit-rate BR from said frame.

51. The decoder as claimed in claim 40, wherein the decode further comprises:

a memory for storing information relating to the bit-rate BR from said frame.

52. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting information relating to the bit-rate BR from said frame.

53. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving information relating to the sampling frequency Fs from said frame.

54. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing information relating to the sampling frequency F_s from said frame.

55. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting information relating to the sampling frequency F_s from said frame.

56. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving information indicating whether a frame has one information packet more than another frame.

57. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing information indicating whether a frame has one information packet more than another frame.

58. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting information indicating whether a frame has one information packet more than another frame.

59. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving a padding bit, said padding bit being ‘

1’

if said frame has one information packet more than a frame with said padding bit being ‘

0’

.

60. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing a padding bit, said padding bit being ‘

1’

if said frame has one information packet more than a frame with said padding bit being ‘

0’

.

61. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving a padding bit in said first frame portion, said bit being ‘

1’

if said frame has one information packet more than a frame with said padding bit being ‘

0’

.

62. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing a padding bit in said first frame portion, said bit being ‘

1’

if said frame has one information packet more than a frame with said padding bit being ‘

0’

.

63. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting a padding bit in said first frame portion, said bit being ‘

1’

if said frame has one information packet more than a frame with said padding bit being ‘

0’

.

64. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving system information identifying said encoded digital signal as a mono audio signal, a bilingual signal, or an intensity stereo audio signal.

65. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing system information identifying said encoded digital signal as a mono audio signal, a bilingual signal, or an intensity stereo audio signal.

66. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting system information identifying said encoded digital signal as a mono audio signal, a bilingual signal, or an intensity stereo audio signal.

67. The decoder as claimed in any one of claims 40 to 60, further comprising a retrieval unit for retrieving from the frame at least one sample representative of at least one quantized sub-signal of said wideband digital audio signal.

68. The decoder as claimed in any one of claims 40 to 60, wherein the decoder further comprises:

a memory for storing at least one sample representative of at least one quantized sub-signal of said wideband digital audio signal.

69. The decoder as claimed in any one of claims 40 to 60, wherein the decoder further comprises:

a detector for detecting in the frame at least one sample representative of at least one quantized sub-signal of said wideband digital audio signal.

70. The decoder as claimed in claim 68, wherein the decoder further comprises:

a dequantizing unit for dequantizing said at least one quantized sub-signal; and

a sub-band synthesis filter unit for converting said dequantized at least one quantized sub-signal into the replica of the wideband digital audio signal.

71. The decoder as claimed in claim 40, wherein the decoder further comprises:

a retrieval unit for retrieving scale factor information from said frame.

72. The decoder as claimed in claim 40, wherein the decoder further comprises:

a memory for storing scale factor information from said frame.

73. The decoder as claimed in claim 40, wherein the decoder further comprises:

a detector for detecting scale factor information from said frame.

74. The decoder as claimed in claim 68, wherein said retrieval unit for retrieving from the frame at least one sample representative of at least one quantized sub-signal further comprises:

means for retrieving bit allocation information in the form of at least one 4-bit word representing the number of bits with which said at least one sample of said at least one quantized sub-signal are represented.

75. The decoder as claimed in claim 69, wherein said detector for detecting from the frame at least one sample representative of at least one quantized sub-signal, further comprises:

means for detecting bit allocation information in the form of at least one 4-bit word representing the number of bits with which said at least one sample of said at least one quantized sub-signal are represented.

76. The decoder as claimed in claim 72, wherein the decoder further comprises:

a retrieval unit for retrieving at least one 6-bit word from the scale factor information representing a scale factor for at least one quantized sub-signal of said wideband digital audio signal.

77. The decoder as claimed in claim 72, wherein the decoder further comprises:

an inhibitor for inhibiting retrieval of samples for a sub-signal when the 4-bit word ‘

0000’

is detected.

78. The decoder as claimed in claim 72, wherein the decoder further comprises:

an inhibitor for inhibiting retrieval of a scale factor for a sub-signal when the 4-bit word ‘

0000’

is detected.

79. The decoder as claimed in claim 40, wherein F_s=48 kHz.

80. The decoder as claimed in claim 40, wherein F_s=44.1 kHz.

81. The decoder as claimed in claim 40, wherein N=32.

82. The decoder as claimed in claim 40, wherein n_s=384.

83. The decoder as claimed in claim 40, wherein BR=384.

84. An apparatus for decoding an encoded frame of wideband digital audio data, the encoded frame of wideband digital audio data having an integer number of audio information packets, said apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

a padding bit reader for determining the value of a padding bit, wherein the padding bit is bit twenty-two in the encoded wideband digital audio data frame, wherein bit 0 is the first bit in the frame, and wherein a padding bit value of 1 indicates that a frame has exactly one more audio information packet than a frame having a padding bit value of 0; and

a decoder for converting the encoded frame of wideband digital audio data into decoded audio data using the value of the padding bit to determine the length of the encoded frame of wideband digital audio data.

85. An apparatus for decoding an encoded frame of wideband digital audio data, the encoded frame of wideband digital audio data havubf an integer number of audio information packets, the apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

means for determining the value of a padding bit, wherein the padding bit is bit twenty-two in the encoded wideband digital audio data frame, wherein bit 0 is the first bit in the frame, and wherein a padding bit value of 1 indicates that a frame has exactly one more audio information packet than a frame having a padding bit value of 0; and

a decoder for converting the encoded frame of wideband digital audio data into decoded audio data using the value of the padding bit to determine the length of the encoded frame of wideband digital audio data.

86. A method for decoding an encoded frame of wideband digital audio data, the encoded frame of wideband digital audio data having an integer number of audio information packets, the method comprising the steps:

receiving the encoded frame of wideband digital audio data;

determining the value of a padding bit, wherein the padding bit is bit twenty-two in the encoded wideband digital audio data frame, wherein bit 0 is the first bit in the frame, and wherein a padding bit value of 1 indicates that a frame has exactly one more audio information packet than a frame having a padding bit value of 0; and

converting the encoded frame of wideband digital audio data into decoded audio data using the read value of the padding bit to determine the length of the encoded frame of wideband digital audio data.

87. An apparatus for decoding an encoded frame of wideband digital audio data, the apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data; and

a decoder for converting the encoded frame of wideband digital audio data into decoded audio data wherein the number of information packets in one frame P is determined according to

P=(BR−

n_s)/(N×

F_s)

where BR is the bit-rate of the wideband digital audio data, a frame contains information for ns samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data, and where if P is an integer, the number of information packets in one frame is P, if P is not an integer, the number of information packets in a number v of the frames is P′

, where P′

is the highest integer whose value is less than P; and

the number of information packets in a number w of the other frames is equal to P′

+1, the numbers v and w being selected such that the average frame rate of the encoded digital signal is substantially equal to F_s/n_s.

88. An apparatus for decoding an encoded frame of wideband digital audio data, the apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

means for searching for a synch word in a first window in the frame occurring after P′

information packets where P′

is the highest integer whose value is less than or equal to P where

P=(BR×

n_s)/(N×

F_s)

wherein BR is the bit-rate of the wideband digital audio data, a frame contains information for ns samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data;

means for searching for the synch word in a second window that is one information packet larger than the first window in the frame occurring after P′

+1 information packets; and

means for decoding wideband digital audio data from encoded data retrieved from the frame.

89. A method for decoding an encoded frame of wideband digital audio data, the method comprising the steps:

receiving the encoded frame of wideband digital audio data;

searching for a synch word in a first window in the frame occurring after P′

information packets, where P′

is the highest integer whose value is less then or equal to P, where

P=(BR×

n_s)/(N×

F_s)

wherein BR is the bit-rate of the wideband digital audio data, a frame contains information for ns samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data;

searching for the synch word in a second window that is one information packet larger than the first window in the frame occurring after P′

+1 information packets; and

decoding wideband digital audio data from encoded data retrieved from the frame.

90. An apparatus for decoding an encoded frame of wideband digital audio data, the apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

means for searching for a synch word in a first window in the frame occurring after P′

information packets, where P′

is the highest integer whose value is less than or equal to P, where

P=(BR×

n_s)/(N×

F_s),

wherein BR is the bit-rate of the wideband digital audio data, a frame contains information for ns samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data;

means for searching for the synch word in a second window, one information packet larger than the first window, in the frame occurring after P′

+1 information packets if the synch word is not found in the first window; and

means for decoding wideband digital audio data from encoded data retrieved from the frame.

91. A method for decoding an encoded frame of wideband digital audio data, the method comprising the steps:

receiving the encoded frame of wideband digital audio data;

searching for a synch word in a first window in the frame occurring after P′

information packets, where P′

is the highest integer whose value is less than or equal to P, where

P=(BR×

n_s)/(N×

F_s),

wherein BR is the bit-rate of the wideband digital audio data, a frame contains information for ns samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data;

searching for the synch word in a second window, one information packet larger than the first window, in the frame occurring after P′

+1 information packets if the synch word is not foUnd in the first window; and

decoding wideband digital audio data from encoded data retrieved from the frame.

92. An apparatus for decoding a first encoded frame of wideband digital audio data, said frame containing, in three non-overlapping frame portions, a sync word, system information, and a padding bit, the apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

means for identifying the sync word;

means for reading the system information;

means for reading the padding bit, wherein the padding bit has a value of 1 if said frame has one information packet more than a frame with said padding bit having a value 0;

means for decoding wideband digital audio data from encoded data retrieved from the first frame; and

means for determining the start of an immediately following second frame of encoded wideband digital audio data.

93. An apparatus for decoding a first encoded frame of wideband digital audio data, said frame containing information related to a scale factor and, in three non-overlapping frame portions, a sync word, system information, and a padding bit, said apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

means for identifying the sync word;

means for reading the system information;

means for reading the padding bit, wherein the padding bit has a value of 1 if said frame has one information packet more than a frame with said padding bit having a value 0;

means for deriving a scale factor from the information related to a scale factor;

means for decoding wideband digital audio data from encoded data retrieved from the first frame; and

means for determining the start of an immediately following second frame of encoded wideband digital audio data.

94. A method for decoding a first encoded frame of wideband digital audio data, said frame containing information related to a scale factor and, in three non-overlapping frame portions, a sync word, system information, and a padding bit, said method comprising the steps:

receiving the encoded frame of wideband digital audio data;

identifying the sync word;

reading the system information;

reading the padding bit;

deriving a scale factor from the information related to a scale factor;

decoding wideband digital audio data from encoded data retrieved from the first frame; and

determining the start of an immediately following second frame of encoded wideband digital audio data.

95. An apparatus for decoding an encoded frame of wideband digital audio data, the encoded frame of wideband digital audio data having an integer number of audio information packets, the apparatus comprising:

an input for receiving the encoded frame of wideband digital audio data;

means for detecting a signal in the frame indicating that the number of audio information packets inserted into the frame by an encoder was determined according to P=(BR×

n_s)/(N×

F_s) is an integer, where BR is the bit-rate of the encoded digital signal and a frame contains information for n_s samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data, where if P is an integer, the number of information packets in one frame is P, if P is not an integer, the number of information packets in a number of frames is P′

, where P′

is the next lower integer following P, and the number of information packets in the other frames is equal to P′

+1; and

means for generating a replica of the wideband digital signal from the encoded wideband digital audio data in the frame.

96. A method for decoding an encoded frame of wideband digital audio data, the encoded frame of wideband digital audio data having an integer number of audio information packets, the method comprising the steps:

receiving the encoded frame of wideband digital audio data;

detecting a signal in the frame indicating that the number of audio information packets inserted into the frame by an encoder was determined according to P=(BR×

n_s)/(N×

F_s) is an integer, where BR is the bit-rate of the encoded digital signal and a frame contains information for n_s samples of the wideband digital audio signal, N is the number of bits, greater than 1, in each information packet, and F_s is the sampling frequency of the wideband digital audio data, where if P is an integer, the number of information packets in one frame is P, if P is not an integer, the number of information packets in a number of frames is P′

, where P′

is the next lower integer following P, and the number of information packets in the other frames is equal to P′

+1; and

generating a replica of the wideband digital signal from the encoded wideband digital audio data in the frame.