Data multiplexing apparatus and multiplexed data demultiplexing apparatus

A method for timeshare-multiplexing a plurality of data signals having variable rates, said method comprising the steps of:

• buffering each of said data signals in respective ones of a plurality of code buffers;
• generating a switching control signal and a header control signal;
• retrieving each of said data signals from said code buffers and grouping the retrieved data signals so as to form respective packets of data each corresponding to a respective variable rate and generating packs of data from the packets of data each having a fixed data length in response to said switching control signal;
• determining if the data contained within the one or more packets of data to be included in a respective pack is less than that which may occupy the respective pack and, in the event of such a determination, for obtaining an amount of data necessary to be added to the included data so as to fill the respective pack from a portion of another packet of data and for adding such data to the respective pack;
• adding, in response to said header control signal, a packet header at a beginning portion of each of said packets and a pack header at a beginning portion of each of said packs including time information;
• and
• storing each said pack of data in a storage medium;
• said time information identifying when the respective pack of data is to be subsequently read from said storage medium.

A demultiplexing apparatus for demultiplexing mutiplexed packs of data stored in a storage medium, each pack having a fixed data length and including a respective pack header and one or more packets of data each having a respective packet header and formed by timeshare-multiplexing a plurality of original data signals having variable rates, into said plurality of original data signals, said apparatus comprising:

• means for retrieving said multiplexed packs of data from said storage medium;
• header separating means for separating each said pack header and packet header from the retrieved packs of data;
• pack time information storing means for receiving each separated pack header;
• switching means for separating said retrieved packs of data into said plurality of original data signals and for successively supplying the separated original data signals therefrom;
• and
• a plurality of buffers each respectively receiving one of said original data signals in succession from said switching means, each of said buffers having a storage capacity at least large enough to accommodate one pack of data having said fixed data length, said buffers supplying said original data signals therefrom.

A demultiplexing apparatus for demultiplexing multiplexed packs of data stored in a storage medium, each pack contained within a respective multiplexing interval having a data length associated therewith and formed by timeshare-multiplexing a plurality of original data signals having variable rates, into said plurality of original data signals, said apparatus comprising:

• means for reading said packs of data from said storage medium and for demultiplexing the read packs of data so as to produce said plurality of original data signals therefrom;
• a plurality of buffers receiving the produced original data signals from said means for demultiplexing for storing said produced original data signals and for reading the stored original data signals therefrom, each of said buffers having a respective storage capacity at least equivalent to a maximum length of data contained in the multiplexing interval;
• and
• delay means for delaying the reading of said stored original data signals by said plurality of buffers by a delay time corresponding to the multiplexing interval.

A demultiplexing apparatus for demultiplexing a plurality of timeshared-multiplexed data signals stored on a storage medium into a plurality of original data signals, said apparatus comprising:

• means for reading said timeshared-multiplexed data signals stored on said storage medium at a predetermined speed and for demultiplexing the read timeshared-multiplexed data signals so as to form a plurality of demultiplexed data signals;
• a plurality of buffers each corresponding to one of the original data signals and having a respective storage area, each of said buffers receiving a respective demultiplexed data signal and storing the received respective demultiplexed data signal therein, said plurality of buffers supplying said original data signals therefrom;
• and
• control means for temporarily stopping the reading performed by said means for reading when there is an absence of space in the storage area of at least one of said plurality of buffers.