Method and apparatus for verifying multiplexing schedule of digital signals and apparatus for multiplexing digital signals

• US 6,285,689 B1
• Filed: 05/20/1997
• Issued: 09/04/2001
• Est. Priority Date: 05/24/1996
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tahara, Katsumi, Yasuda, Mikita, Oishi, Noriaki, Negishi, Shinji
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): PHAN, MAN U
• Application Number:
  US08/859,402
• Time in Patent Office: 1,568 Days
• Field of Search: 370/465, 370/468, 370/537, 370/538, 370/487, 370/490, 370/522, 348/465, 348/906, 348/845.3, 348/7, 348/10, 348/423, 348/515
• US Class Current: 370/537
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/2389 Multiplex stream processing, e.g. multiplex stream encrypting
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/4344 Remultiplexing of multiplex streams, e.g. by modifying time stamps or remapping the packet identifiers
• CPC Class Codes: H04N 21/4385 Multiplex stream processing, e.g. multiplex stream decrypting
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 7/52 Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal assembling of a multiplex stream by combining a video stream with other content or additional data, remultiplexing of multiplex streams, insertion of stuffing bits into the multiplex stream, assembling of a packetised elementary stream at server side H04N21/236; disassembling of a multiplex stream, remultiplexing of multiplex streams, extraction or processing of Service Information, disassembling of packetised elementary stream at client side H04N21/434

Abstract

A method and an apparatus for verifying a multiplexing schedule of digital signals and an apparatus for multiplexing the digital signals are provided. The verifying method includes the processes of extracting access unit information about each decoding unit from each elementary stream of the digital signal, determining schedule information about time division of each elementary stream, based on the access unit information, and verifying whether or not the multiplexing schedule for generating the multiplexed stream is valid, based on the access unit information and the schedule information. The verifying apparatus includes an extracting section for extracting access unit information about a decoding unit from each elementary stream of the digital signal, a determining section for determining schedule information about time division of the elementary stream, based on the access unit information, and a verifying section for verifying whether or not the multiplexing schedule for generating the multiplexed stream is valid, based on the access unit information and the schedule information.

Claims

1. A method for verifying the validity of a multiplexing schedule for generating a time-divisional multiplexed stream comprised of a sequence of access units each being assigned a plurality of data packets multiplexed from a plurality of elementary streams of compressed digital signals, comprising the steps of:

determining access unit information about the assignment of said plurality of data packets to respective access units;

determining schedule information about the multiplexing of said elementary streams, based on said access unit information; and

verifying the validity of the multiplexing schedule based on the access unit information and the schedule information to determine whether, upon demultiplexing and decoding, it is possible for the elementary streams to be synchronously reproduced by a decoder on the basis of whether a decoder buffer will overflow or underflow.

2. A method for verifying the validity of a multiplexing schedule for generating a time-divisional multiplexed stream comprised of a sequence of access units each being assigned a plurality of data packets multiplexed from a plurality of elementary streams of compressed digital signals, comprising the steps of:

determining access unit information about the assignment of said plurality of data packets to respective access units;

determining a schedule information for time-divisionally multiplexing said plurality of elementary streams and generating said multiplexed stream according to said access unit information and said schedule information;

extracting said schedule information from said multiplexed stream; and

verifying the validity of the multiplexing based on the access unit information and the schedule information to determine whether, upon demultiplexing and decoding, it is possible for the elementary streams to be synchronously reproduced by a decoder on the basis of whether a decoder buffer will overflow or underflow.

3. An apparatus for verifying the validity of a multiplexing schedule for generating a time-divisional multiplexed stream comprised of a sequence of access units each being assigned a plurality of data packets multiplexed from a plurality of elementary streams of compressed digital signals, comprising:

a preprocessor for determining access unit information about the assignment of said plurality of data packets to respective access units;

a determining section for determining schedule information about the multiplexing of said elementary streams, based on said access unit information; and

a verifying section for verifying the validity of the multiplexing schedule based on said access unit information and said schedule information to determine whether, upon demultiplexing and decoding, it is possible for the elementary streams to be synchronously reproduced by a decoder on the basis of whether a decoder buffer will overflow or underflow.

4. An apparatus for verifying the validity of a multiplexing schedule for generating a time-divisional multiplexed stream comprised of a sequence of access units each being assigned a plurality of data packets multiplexed from a plurality of elementary streams of compressed digital signals, comprising the steps of:

a preprocessor for determining access unit information about the assignment of said plurality of data packets to respective access units;

a generating section for determining a schedule information for time-divisionally multiplexing said plurality of elementary streams and for generating said multiplexed stream according to said access unit information and said schedule information;

an extracting section for extracting said schedule information from said multiplexed stream; and

a verifying section for verifying the validity of the multiplexing schedule based on said access unit information and said schedule information to determine whether, upon demultiplexing and decoding, it is possible for the elementary streams to be synchronously reproduced by a decoder on the basis of whether a decoder buffer will overflow or underflow.