APPARATUS AND METHOD FOR ENCODING AND DECODING AN AUDIO SIGNAL USING AN ALIGNED LOOK-AHEAD PORTION
First Claim
1. An apparatus for encoding an audio signal comprising a stream of audio samples, comprising:
- a windower for applying a prediction coding analysis window to the stream of audio samples to acquire windowed data for a prediction analysis and for applying a transform coding analysis window to the stream of audio samples to acquire windowed data for a transform analysis,wherein the transform coding analysis window is associated with audio samples within a current frame of audio samples and with audio samples of a predefined portion of a future frame of audio samples being a transform-coding look-ahead portion,wherein the prediction coding analysis window is associated with at least the portion of the audio samples of the current frame and with audio samples of a predefined portion of the future frame being a prediction coding look-ahead portion,wherein the transform coding look-ahead portion and the prediction coding look-ahead portion are identical to each other or are different from each other by less than 20% of the prediction coding look-ahead portion or less than 20% of the transform coding look-ahead portion; and
an encoding processor for generating prediction coded data for the current frame using the windowed data for the prediction analysis or for generating transform coded data for the current frame using the windowed data for the transform analysis.
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Abstract
An apparatus for encoding an audio signal having a stream of audio samples has: a windower for applying a prediction coding analysis window to the stream of audio samples to obtain windowed data for a prediction analysis and for applying a transform coding analysis window to the stream of audio samples to obtain windowed data for a transform analysis, wherein the transform coding analysis window is associated with audio samples within a current frame of audio samples and with audio samples of a predefined portion of a future frame of audio samples being a transform-coding look-ahead portion, wherein the prediction coding analysis window is associated with at least the portion of the audio samples of the current frame and with audio samples of a predefined portion of the future frame being a prediction coding look-ahead portion, wherein the transform coding look-ahead portion and the prediction coding look-ahead portion are identically to each other or are different from each other by less than 20%; and an encoding processor for generating prediction coded data or for generating transform coded data.
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Citations
26 Claims
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1. An apparatus for encoding an audio signal comprising a stream of audio samples, comprising:
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a windower for applying a prediction coding analysis window to the stream of audio samples to acquire windowed data for a prediction analysis and for applying a transform coding analysis window to the stream of audio samples to acquire windowed data for a transform analysis, wherein the transform coding analysis window is associated with audio samples within a current frame of audio samples and with audio samples of a predefined portion of a future frame of audio samples being a transform-coding look-ahead portion, wherein the prediction coding analysis window is associated with at least the portion of the audio samples of the current frame and with audio samples of a predefined portion of the future frame being a prediction coding look-ahead portion, wherein the transform coding look-ahead portion and the prediction coding look-ahead portion are identical to each other or are different from each other by less than 20% of the prediction coding look-ahead portion or less than 20% of the transform coding look-ahead portion; and an encoding processor for generating prediction coded data for the current frame using the windowed data for the prediction analysis or for generating transform coded data for the current frame using the windowed data for the transform analysis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of encoding an audio signal comprising a stream of audio samples, comprising:
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applying a prediction coding analysis window to the stream of audio samples to acquire windowed data for a prediction analysis and applying a transform coding analysis window to the stream of audio samples to acquire windowed data for a transform analysis, wherein the transform coding analysis window is associated with audio samples within a current frame of audio samples and with audio samples of a predefined portion of a future frame of audio samples being a transform-coding look-ahead portion, wherein the prediction coding analysis window is associated with at least the portion of the audio samples of the current frame and with audio samples of a predefined portion of the future frame being a prediction coding look-ahead portion, wherein the transform coding look-ahead portion and the prediction coding look-ahead portion are identical to each other or are different from each other by less than 20% of the prediction coding look-ahead portion or less than 20% of the transform coding look-ahead portion; and generating prediction coded data for the current frame using the windowed data for the prediction analysis or for generating transform coded data for the current frame using the windowed data for the transform analysis. - View Dependent Claims (25)
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16. An audio decoder for decoding an encoded audio signal, comprising:
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a prediction parameter decoder for performing a decoding of data for a prediction coded frame from the encoded audio signal; a transform parameter decoder for performing a decoding of data for a transform coded frame from the encoded audio signal, wherein the transform parameter decoder is configured for performing a spectral-time transform and for applying a synthesis window to transformed data to acquire data for the current frame and a future frame, the synthesis window comprising a first overlap portion, an adjacent second non-overlapping portion and an adjacent third overlap portion, the third overlap portion being associated with audio samples for the future frame and the non-overlap portion being associated with data of the current frame; and an overlap-adder for overlapping and adding synthesis windowed samples associated with the third overlap portion of a synthesis window for the current frame and synthesis windowed samples associated with the first overlap portion of a synthesis window for the future frame to acquire a first portion of audio samples for the future frame, wherein a rest of the audio samples for the future frame are synthesis windowed samples associated with the second non-overlapping portion of the synthesis window for the future frame acquired without overlap-adding, when the current frame and the future frame comprise transform-coded data. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A method of decoding an encoded audio signal, comprising:
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performing a decoding of data for a prediction coded frame from the encoded audio signal; performing a decoding of data for a transform coded frame from the encoded audio signal, wherein performing a decoding of data for a transform coded frame comprises performing a spectral-time transform and applying a synthesis window to transformed data to acquire data for the current frame and a future frame, the synthesis window comprising a first overlap portion, an adjacent second non-overlapping portion and an adjacent third overlap portion, the third overlap portion being associated with audio samples for the future frame and the non-overlap portion being associated with data of the current frame; and overlapping and adding synthesis windowed samples associated with the third overlap portion of a synthesis window for the current frame and synthesis windowed samples associated with the first overlap portion of a synthesis window for the future frame to acquire a first portion of audio samples for the future frame, wherein a rest of the audio samples for the future frame are synthesis windowed samples associated with the second non-overlapping portion of the synthesis window for the future frame acquired without overlap-adding, when the current frame and the future frame comprise transform-coded data. - View Dependent Claims (26)
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Specification