Picture encoding method and apparatus and picture decoding method and apparatus

Abstract

A picture encoding method includes receiving an input video signal, encoding the video signal using a reference picture signal to generate a video code stream, encoding the reference picture signal to generate a reference picture code stream, and multiplexing the video code stream with the reference picture code stream to generate an output code stream.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present divisional application claims the benefit of priority under 35 U.S.C. §120 to application Ser. No. 10 / 661,697, filed Sep. 15, 2003, which is a Continuation Application of PCT Application No. PCT / JP03 / 00426, filed Jan. 20, 2003, which was not published under PCT Article 21(2) in English; and under 35 U.S.C. § 119 from Japanese applications Nos. 2002-010875, filed on Jan. 18, 2002, and 2003-010135, filed on Jan. 17, 2003, the entire contents of each are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a picture encoding method of compression-encoding a picture in a few number of bits and a picture decoding method of playing back a picture by decoding a code stream obtained by compression encoding and, more particularly, to a picture encoding method and apparatus and a picture decoding method and apparatus which can make a recovery from ...

AI Technical Summary

Benefits of technology

"The present invention provides a picture encoding and decoding method and apparatus that can quickly recover from errors, exhibit high efficiency, and need not perform any re-encoding. The method involves receiving an input video signal, encoding it using a reference picture signal to generate a video code stream, and multiplexing it with a reference picture code stream to generate an output code stream. The decoding method involves receiving an input code stream containing a video code stream and a reference picture code stream, decoding the reference picture code stream to generate a first reference picture signal, and selectively using one of a second reference picture signal obtained from a previous picture signal and the first reference picture signal to generate a playback picture signal. The technical effects of the invention include faster recovery from errors, higher efficiency, and no need for re-encoding."

Problems solved by technology

First, in a communication path with the possibility of being mixed with errors, such as a radio communication path, performing only encoding will lead to considerable deterioration in decoded picture quality upon occurrence of an error.

When errors occur in signals such as a sync signal, mode information, and motion vector information, in particular, picture quality noticeably deteriorates.

A predictive picture is generated by using the erroneous picture, and the residual error is added to the predictive error.

As a consequence, even if subsequent frames are properly decoded, proper pictures cannot be obtained from the subsequent frames unless information is sent in an encoding mode (INTRA mode) of encoding pictures only within frames without using the differences between the frames or the influence of the error gradually wanes to restore the original pictures.

Subsequently, residual errors are added to wrong pictures.

In this periodic refresh method, however, although an increase in the number of coded bits can be suppressed, a long period of time is required to recover a normal state.

Although this scheme can correct errors that occur randomly, it has difficulty in coping with errors of several hundred bits that consecutively occur in a burst manner.

Even if the scheme can cope with such errors, considerable redundancy occurs.

As described above, according to the conventional picture encoding techniques, loss of information due to an error causes a great deterioration in picture quality.

In addition, a technique such as the periodic refresh method of reconstructing information lost due to an error requires a long period of time to achieve error recovery in consideration of the encoding efficiency.

Shortening the time required for recovery will increase the number of encoded bits to result in a deterioration in encoding efficiency.

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