US 5,710,598 AGranted

Picture compressing and expanding apparatus

AssigneeMega Chips Corporation

InventorsYukihiro Ukai, Takashi Tsuchitani

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Abstract

A decoding speed is improved. A processing method is changed in variable length decoders depending on whether only one piece of data is to be decoded or two or more pieces of data are to be decoded, thereby suppressing an increase in the size of hardware as much as possible and increasing a processing speed. Although irregular data are created in the first cycle when a large scale decoder having a slow processing speed processes data, a delay apparatus delays data which include the irregular data and data which are supplied from the large scale decoder without a delay are filled in the irregular data portion. As a result, the irregular portion of the data is compensated for and a relative delay of the processing is prevented.

A picture compressing and expanding apparatus comprising a compression part for compressing a picture signal and an expansion part for decoding and expanding data of variable length codes compressed by said compression part, wherein said expansion part comprises:

a small scale decoder for decoding one piece of compressed data;
a large scale decoder having a processing speed which is approximately half that of said small scale decoder and decodes two or more pieces of said compressed data;
input data control means for supplying said data of variable length codes compressed by said compression part to said small scale decoder and said large scale decoder at the same time;
first switching means for switching and outputting output data supplied from said small scale decoder and output data supplied from said large scale decoder;
delaying means for delaying output data supplied from said first switching means by a unit time;
second switching means for switching and outputting the output data supplied from said first switching means and output data supplied from said delaying means in accordance with a predetermined timing signal;
and
timing control means for generating said predetermined timing signal which causes said second switching means to switch from the output data supplied from said delaying means to the output data supplied from said first switching means,
said small scale decoder comprises judging means for determining whether received data are one piece of data or two or more pieces of data, and
said timing means comprises:
irregular timing detecting means for detecting irregular data which are created when said first switching means switches the output data supplied from said small scale decoder and the output data supplied from said large scale decoder in accordance with a judgement signal which is yielded by said judging means for said small scale decoder;
and
timing signal output means for said predetermined timing signal to said second switching means in accordance with a signal received from said timing control means.

10 more elements

Facts

Application

08/534,032Filed 26 Sep 1995

Priority

JP 6-23309428 Sep 1994

Granted

20 Jan 1998

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

H03M 7/425
Using table look-up for the coding or decoding process, e.g. using read-only memory: for the decoding process only
H04N 19/423
Characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software…
H04N 19/44
Methods or arrangements for coding, decoding, compressing or decompressing digital video signals: decoders specially adapted therefor, e.g. video…
H04N 19/13
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: adaptive entropy coding, e.g. adaptive…

Abstract

Claims5