Method of making a window type decision based on MDCT data in audio encoding
First Claim
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1. A method of execution by a computer, the method comprising:
- detecting an indication of a transition from a steady signal to a transient signal in a next frame of audio data;
deciding that a preliminary window type of the next frame is a short window type; and
determining a window type of a current frame of data based on the preliminary window type of the current frame and a window type of a previous frame of data, the determination of the window type of the current frame favoring use of a long window type over use of the short window type, wherein the audio data is transformed into a frequency domain using a transformation range defined by the window type.
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Abstract
Preliminary Modified Discrete Cosine Transform (MDCT) coefficients are computed for a current frame of data and a next frame of data using a long window type. The computed preliminary MDCT coefficients of the current and next frames are then used to determine the window type of the current frame. If the determined window type is not the long window type, final MDCT coefficients are computed for the current frame using the determined window type.
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Citations
17 Claims
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1. A method of execution by a computer, the method comprising:
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detecting an indication of a transition from a steady signal to a transient signal in a next frame of audio data; deciding that a preliminary window type of the next frame is a short window type; and determining a window type of a current frame of data based on the preliminary window type of the current frame and a window type of a previous frame of data, the determination of the window type of the current frame favoring use of a long window type over use of the short window type, wherein the audio data is transformed into a frequency domain using a transformation range defined by the window type. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A computer readable medium that provides instructions, which when executed on a processor cause the processor to perform a method comprising:
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detecting an indication of a transition from a steady signal to a transient signal in a next frame of data; and deciding that a preliminary window type of the next frame is a short window type; and determining a window type of a current frame of data based on the preliminary window type of the current frame and a window type of a previous frame of data, the determination of the window type of the current frame favoring use of a long window type over use of the short window type. - View Dependent Claims (12, 13)
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14. A computerized system comprising:
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a memory; and at least one processor coupled to the memory, the at least one processor executing a set of instructions which cause the at least one processor to detect an indication of a transition from a steady signal to a transient signal in a next frame of data, decide that a preliminary window type of the next frame is a short window type, and determine a window type of a current frame of data based on the preliminary window type of the current frame and a window type of a previous frame of data, the determination of the window type of the current frame favoring use of a long window type over use of the short window type. - View Dependent Claims (15, 16)
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17. An apparatus comprising:
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means for detecting an indication of a transition from a steady signal to a transient signal in a next frame of audio data; and means for deciding that a preliminary window type of the next frame is a short window type; and means for determining a window type of a current frame of data based on the preliminary window type of the current frame and a window type of a previous frame of data, the determination of the window type of the current frame favoring use of a long window type over use of the short window type, wherein the audio data is transformed into a frequency domain using a transformation range defined by the window type.
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Specification