Techniques for quantization of spectral data in transcoding
AssigneeMicrosoft Corporation
InventorsWei-Ge Chen, Ming-Chieh Lee
Life of this patent
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Abstract
A transcoder reduces excess requantization error in quantization of spectral data. The transcoder phase shifts data decompressed by a decompressor. The phase shifting causes a change to corresponding spectral data produced in later transform coding of the decompressed data. When the spectral data is then quantized to reduce bitrate, the earlier phase shifting reduces excess requantization error. After transcoding, a second decompressor can compensate for the phase shifting by, for example, reverse shifting by the amount of the phase shift. Instead of phase shifting, the transcoder can reduce excess requantization error by, for example, adding random noise to the decompressed data or changing transform block sizes.
Claims44
A system for processing information by performing a method comprising:
- receiving information that has been decompressed after a first compression, the first compression including a first quantization;
- and
- phase-shifting the received information to alter spectral information produced by transform coding the phase-shifted information in a second compression, thereby reducing requantization error associated with a second quantization in the second compression.
A system for processing information by performing a method comprising:
- receiving information that has been decompressed after a first compression, the first compression including a first quantization;
- and
- adding random noise to the received information to alter spectral information produced by transform coding in a second compression, thereby reducing requantization error associated with a second quantization in the second compression.
A system for processing information by performing a method comprising:
- receiving information that has been decompressed after a first compression, the first compression including a first quantization;
- and
- changing transform block size of one or more of plural blocks of the received information to alter spectral information produced by transform coding in a second compression, thereby reducing requantization error associated with a second quantization in the second compression.
A method comprising:
- receiving compressed information that has been compressed in a first compression including a first quantization;
- decompressing the compressed information to produce decompressed information;
- phase-shifting the decompressed information to alter spectral information produced by transform coding the phase-shifted information in a second compression, thereby reducing requantization error associated with a second quantization in the second compression;
- performing the second compression on the phase-shifted information, thereby producing recompressed information;
- and
- outputting the recompressed information.
Dependencies are inferred from the claim text.