Browse Prior Art Database

Pause Compression/ Encode

IP.com Disclosure Number: IPCOM000050993D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Related People

Crauwels, GL: AUTHOR [+3]

Abstract

A significant amount of normal speech consists of silence. A function of a microprocessor controller in a speech store and forward system, for example, is to compress and encode the pauses to reduce the amount of storage required and also to restore the pauses when the stored speech (audio) is played out. In the drawing, the process states are as follows: State 1 Normal data. Cycle Steal directly to main storage. 2 Overhang data. Cycle Steal 127 words to main storage. 3 Pause. Encoded data into delay buffer. Cycle through delay buffer. 4 Pause end. Store pause code in main storage. Round up data. Cycle delay buffer while storing delay buffer contents in main storage. 5 Normal data. Cycle Steal directly to main storage.

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Pause Compression/ Encode

A significant amount of normal speech consists of silence.

A function of a microprocessor controller in a speech store and forward system, for example, is to compress and encode the pauses to reduce the amount of storage required and also to restore the pauses when the stored speech (audio) is played out. In the drawing, the process states are as follows:
State 1 Normal data. Cycle Steal directly to main storage.

2 Overhang data. Cycle Steal 127 words to main storage.

3 Pause. Encoded data into delay buffer. Cycle through delay

buffer.

4 Pause end. Store pause code in main storage. Round up data.

Cycle delay buffer while storing delay buffer contents in

main storage.

5 Normal data. Cycle Steal directly to main storage.

For pause compression, a pause is detected when the input audio signal falls below a threshold level for a predetermined length of time. When this occurs, it will be reported to the microprocessor by a "Quiet Detect" signal provided by the audio device.

It is necessary to encode a small period of quiet as data to reproduce the natural ends of sounds (State 2). This time is called the "overhang" and is set at the length of a delay buffer. After the overhang period, the controller will stop sending encoded data for the port and will begin timing the period of silence. This time is counted in one-word increments, with one word being the amount of time to deserialize 16 bits of audio information at the selected coding rate.

If Quiet Detect goes away during the overhang for more than one word time, the process returns to State 1 and the entire period is recorded as audio.

While timing the p...