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US 5,920,833 AGranted
Audio decoder employing method and apparatus for soft-muting a compressed audio signal
AssigneeLSI Logic Corporation
InventorGregg Dierke
Life of this patent
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Abstract
An MPEG audio decoder includes a Vector FIFO buffer and a windowed polyphase filter. Groups of vector samples are zeroed out prior to storage in the Vector FIFO buffer when it is desired to soft-mute an audio output of the decoder.
Claims27
A method of processing an encoded audio signal, comprising the steps of:
- decoding the encoded signal into vector samples;
- replacing those vector samples decoded when a soft-mute is commanded with neutral data;
- after said replacing step, buffering the decoded vector samples;
- and
- filtering the decoded vector samples to generate PCM samples.
2 more elements
A method of generating an analog audio signal in response to an MPEG-encoded signal, comprising the steps of:
- processing the MPEG-encoded audio signals into IDCT vector samples;
- replacing the vector samples with neutral data when a soft-mute is commanded:
- after said replacing step, buffering the IDCT vector samples in groups on a first-in, first-out basis;
- and
- reconstructing the audio signal from an output of the filter.
2 more elements
An audio core module, comprising:
- a vector FIFO;
- a windowed polyphase filter having an input coupled to an output of the vector FIFO;
- and
- at least one gate for replacing data for the Vector FIFO buffer with neutral data when a soft-mute is commanded.
1 more element
An audio core module comprising:
- means for decoding an encoded signal;
- means, responsive to the decoding means, for zeroing out the decoded signal when a soft mute is commanded;
- means for buffering an output of the zeroing-out means;
- and
- means for filtering an output of the buffering means to produce samples that can be reconstructed into an analog audio signal.
2 more elements
An audio decoder comprising:
- an audio core module;
- an audio host module coupled to the audio core module;
- an audio output module coupled to the audio core module;
- at least one gate for zeroing out an output of the audio output module during a soft-mute;
- and
- a filter for spreading out an output of the at least one gate, the filter providing digital samples that can be reconstructed into an analog audio signal.
3 more elements
A method of performing a soft-mute in an audio encoder, the method comprising the steps of:
- parsing an input bit stream to obtain Discrete Cosine Transform (DCT) vector samples;
- dequantizing, rescaling, and transforming the DCT vector samples to form Inverse Discrete Cosine Transform (IDCT) vector samples;
- concealing decoding errors by replacing the IDCT vector samples with neutral data by AND'ing the neutral data with the IDCT vector samples;
- buffering the IDCT vector samples, after replacing the IDCT vector samples with neutral data, using a Vector FIFO buffer;
- and
- blending the IDCT vector samples using a windowed polyphase filter to form digital samples.
3 more elements
Dependencies are inferred from the claim text.