US 8,428,942 B2Granted

Method and apparatus for re-encoding signals

AssigneeThomson Licensing

InventorsPeter Jax, Oliver Wuebbolt, Johannes Boehm

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Abstract

At the time of encoding audio content, the finally required data rate for delivery to the customer may be unknown. A data format is disclosed that is optimized for serving as Intermediate Format for efficient and fast recoding, to obtain one or more standard complying lossy encoded data streams with flexible data rates. Encoding can be performed in two steps that are inter-coordinated for cooperating, but may be locally and/or temporally separate. Between the partial encoders encoding parameters and/or auxiliary data are transmitted in a separate parameter enhancement layer, which complements a lossy data stream and can be used by the second encoder or transcoder for fast and computationally efficient implementation of the second encoding step. An additional lossless enhancement layer allows lossless reconstruction.

Claims6

Dependent claims

A method for transcoding a signal that comprises at least a first and a second data stream, wherein the first data stream is self-contained and comprises side information and a lossy encoded source signal with quantized MDCT parameters, and wherein said side information comprises data describing the quantization process by which said quantized MDCT parameters were obtained, the method comprising the steps of:

extracting from the first data stream the encoded source signal and said side information;
decoding said side information extracted from the first data stream;
decoding the extracted encoded source signal using said decoded side information, whereby decoded reconstructed parameters are obtained;
extracting from the second data stream finely quantized control parameters that were used for encoding the lossy encoded source signal, and finely quantized MDCT coefficients, wherein the finely quantized control parameters and the finely quantized MDCT coefficients are finer quantized than those extracted from the first data stream;
decoding said control parameters extracted from the second data stream;
conditionally decoding said finely quantized MDCT coefficients, wherein from said decoded reconstructed parameters at least the quantized MDCT parameters are used;
re-quantizing and re-encoding the conditionally decoded finely quantized MDCT coefficients, wherein a bit allocation algorithm is used that is controlled according to the decoded side information, the decoded encoding control parameters and a required data rate, and wherein an encoded output signal and encoded output side information are generated;
and
multiplexing the encoded output signal and the encoded output side information into a transcoded signal.

6 more elements

An apparatus for transcoding a signal that comprises at least a first and a second data stream, wherein the first data stream is self-contained and comprises a lossy encoded source signal with quantized MDCT parameters, said side information comprising data describing the quantization process by which said quantized MDCT parameters were obtained, the apparatus comprising:

means for extracting from the first data stream the encoded source signal and said side information;
means for decoding said side information extracted from the first data stream;
means for decoding the extracted encoded source signal using said decoded side information, whereby decoded reconstructed parameters are obtained;
means for extracting from the second data stream finely quantized encoding control parameters and MDCT coefficients, wherein the finely quantized control parameters and the finely quantized MDCT coefficients are finer quantized than those extracted from the first data stream;
means for decoding said encoding control parameters extracted from the second data stream;
conditional decoder means for conditionally decoding said finely quantized MDCT coefficients, wherein from said decoded reconstructed parameters at least quantized MDCT parameter are used;
means for generating control information according to the decoded side information, the decoded additional side information and a required data rate;
means for re-quantizing and re-encoding the reconstructed parameters, wherein a bit allocation algorithm is used that is controlled according to said control information, wherein an encoded output signal and encoded output side information are generated;
and
means for multiplexing the encoded output signal and the encoded output side information into a transcoded signal.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/227,189Filed 12 May 2007
Priority: EP 0611386712 May 2006
Published: US 2009/0106031 A123 Apr 2009
Granted: 23 Apr 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G10L 19/24
Vocoders using multiple modes: variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical…
G10L 19/173
Vocoder architecture: transcoding, i.e. converting between two coded representations avoiding cascaded coding-decoding
G10L 19/0204
Using spectral analysis, e.g. transform vocoders or subband vocoders: using subband decomposition
G10L
Speech analysis techniques or speech synthesis