Method and apparatus for encoding and for decoding a digital information signal

• US 20030167165A1
• Filed: 02/24/2003
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Bohm, Johannes, Schroder, Ernst F.
• Granted Patent: US 6,903,664 B2
• Time in Patent Office: Days
• US Class Current: 704/212
• 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

Abstract

Original digital audio signals are represented as PCM sample values wherein the distance between the values corresponds to the sampling frequency. Digital signals can have a length that is an integer multiple only of this time element. In particular coded digital audio signals are processed block-based, leading to a total length that is a multiple only of the block unit. According to the invention, information about the exact length of the original signal is transferred together with the encoded audio information. Additionally, an information value can be transferred that represents the total encoder and/or decoder delay. The decoder extracts these items of information and adjusts the total length of the decoded signal by cutting off samples from the decoded program or track.

Claims

1. Method for encoding a digital information signal—

e.g. an audio signal—

having an arbitrary number of original sample values for a specific program or track and thus having an arbitrary length, wherein the encoding operation is based on value blocks related to said sample values, said value blocks each containing multiple values, wherein the encoded digital information signal is output as a code that, when correspondingly decoded, represents a decoded digital information signal having a total length of multiple units corresponding to the length or lengths of said value blocks, wherein data representing said original sample values arbitrary-length number are supplementing at least one frame of said encoded digital information signal output code, for example the last frame or the penultimate frame of said encoded digital information signal,

or are repeatedly arranged in said encoded digital information signal.

2. Method according to claim 1, wherein in addition data representing the basic delay caused by said encoding operation are supplementing frames of said encoded digital information signal output code, for example in the first or the second frame of said encoded digital information signal.

3. Method according to claim 1, wherein said data representing said original sample values arbitrary-length number and said data representing the basic delay caused by said encoding operation are arranged in ancillary parts of said frames, in particular in an error-protected fashion, e.g. CRC protected.

11. Storage medium, in particular an optical disc or hard disc, containing or having recorded on it a sequence of digital information signal data—

e.g. audio signal data—

that are encoded according to the method of claim 1, wherein, when the data of said storage medium is input into an apparatus according to claim 9, said digital information signal data cause carrying out a method according to claim 4.

4. Method for decoding an encoded digital information signal—

e.g. an audio signal—

having an arbitrary number of original sample values for a specific program or track and thus having an arbitrary original length, wherein the decoding operation is based on value blocks related to said sample values, said value blocks each containing multiple values, wherein the encoded digital information signal is input as a code that after decoding represents a decoded digital information signal having a length of multiple units corresponding to the length or lengths of said value blocks, wherein data representing said original sample values arbitrary-length number and supplementing frames of the encoded digital information signal input code, for example the last frame or the penultimate frame of said encoded digital information signal, or being repeatedly arranged in said encoded digital information signal, are used for limiting the block unit based total length of the decoded digital information signal to said arbitrary original length.

5. Method according to claim 4, wherein in addition data representing the basic encoder delay, which data are supplementing frames of said encoded digital information signal input code, for example in the first or the second frame of said encoded digital information signal, are used for removing a corresponding number of output sample values from the beginning of the decoded digital information signal.

6. Method according to claim 4, wherein said data representing said original sample values arbitrary-length number and said data representing the basic delay caused by said encoding operation are extracted from ancillary parts of said frames, in particular in an error-protected fashion, e.g. CRC protected.

7. Method according to claim 5, wherein a basic decoder delay value is used together with said data representing said basic encoder delay for removing a corresponding number of output sample values from the beginning of the decoded digital information signal.

8. Apparatus for encoding a digital information signal—

e.g. an audio signal—

having an arbitrary number of original sample values for a specific program or track and thus having an arbitrary length, said value blocks each containing multiple values, said apparatus including;

means for encoding said digital information signal, wherein the encoding operation is based on value blocks related to said sample values and which output the encoded digital information signal as a code that, when correspondingly decoded, represents a decoded digital information signal having a total length of multiple units corresponding to the length or lengths of said value blocks;

means for providing data representing said original sample values arbitrary-length number;

means for supplementing at least one frame of said encoded digital information signal output code with said data representing said original sample values arbitrary-length number, for example the last frame or the penultimate frame of said encoded digital information signal, or,

means for arranging repeatedly in said encoded digital information signal said data representing said original sample values arbitrary-length number.

9. Apparatus for decoding an encoded digital information signal—

e.g. an audio signal—

having an arbitrary number of original sample values for a specific program or track and thus having an arbitrary original length, said apparatus including;

means for decoding said encoded digital information signal, based on value blocks related to said sample values, said value blocks each containing multiple values, wherein the encoded digital information signal is input as a code that after decoding represents a decoded digital information signal having a length of multiple units corresponding to the length or lengths of said value blocks;

means for extracting from frames of said encoded digital information signal code, for example from the last frame or from the penultimate frame of said encoded digital information signal, data representing said original sample values arbitrary-length number;

means for providing said means for decoding with information derived from said arbitrary-length number data for limiting the block unit based total length of the decoded digital information signal to said arbitrary original length.

10. Apparatus according to claim 9, wherein said data representing said original sample values arbitrary-length number and said data representing the basic delay caused by said encoding operation are extracted from ancillary parts of said frames, in particular in an error-protected fashion, e.g. CRC protected.