Methods and devices for coding and decoding digital signals, and systems using them

Method of decoding a coded digital signal, the coded digital signal resulting from an original digital signal decomposed into a plurality of subsignals, at least one subsignal being coded by means of a coding technique among a plurality of coding techniques, the method comprising the steps of:

• applying a plurality of decoding techniques to at least one coded subsignal, and
• if at least two decoding techniques are acceptable for at least one coded subsignal, reading in the stream of coded subsignals an item of information making it possible to select a decoding technique among the decoding techniques.

Apparatus for decoding a coded digital signal, the coded digital signal resulting from an original digital signal decomposed into a plurality of subsignals, at least one subsignal being coded by means of a coding technique among a plurality of coding techniques, the apparatus comprising:

• applying means for applying a plurality of decoding techniques to at least one coded subsignal, and
• reading means for reading in the stream of coded subsignals an item of information making it possible to select a decoding technique among decoding techniques if at least two decoding techniques are acceptable for at least one coded subsignal.

Method of coding a digital signal divided into a plurality of subsignals comprising the steps of:

• coding subsignals so as to produce a stream of coded subsignals, and
• for at least one coded subsignal, if the coded subsignal can be decoded within the meaning of a predetermined likelihood criterion, setting a predetermined value on an item of information for the coded subsignal an indexing the coded subsignals by the items of informations for the coded subsignals.

Method of decoding a stream comprising coded subsignals and items of informations, the method comprising the steps of:

• reading items of informations relating to the decoding from the stream, the items of informations being set within the meaning of a predetermined likelihood criterion, and
• decoding subsignals according to the items of informations read in said reading step.

Method of coding a digital signal divided into a plurality of subsignals comprising the steps of:

• coding subsignals so as to produce a stream of coded subsignals;
• and
• if at least the decoding of one coded subsignal by at least two different techniques is acceptable, indexing said coded subsignal by an item of information.

Method of decoding a coded digital signal, the coded signal resulting from an original digital signal decomposed into a plurality of subsignals, the subsignals being coded by means of a coding technique among a plurality of coding techniques, the method comprising the steps of:

• applying a plurality of decoding techniques to a coded subsignal, and
• if at least two decoding techniques are acceptable, reading an item of information making it possible to select a decoding technique among decoding techniques from the stream of coded signals.

Apparatus for coding a digital signal divided into a plurality of subsignals comprising:

• coding means for coding subsignals so as to produce a stream of coded subsignals;
• and
• indexing means for setting to a predetermined value an item of information for a coded subsignal if the coded subsignal can be decoded within the meaning of a predetermined likelihood criterion and for indexing the coded subsignals by the items of informations for the coded subsignals.

Apparatus for decoding a stream comprising coded subsignals and items of informations comprising:

• reading means for reading items of informations relating to the decoding from the stream of coded subsignals, the items being set within the meaning of a predetermined likelihood criterion;
• and
• decoding means for decoding subsignals according to items of informations read by said reading means.

Apparatus for coding a digital signal divided into a plurality of subsignals comprising:

• coding means for coding subsignals so as to produce a stream of coded subsignals;
• and
• indexing means for indexing the coded subsignal by an item of information if at least the decoding of one coded subsignal by at least two different techniques is acceptable.

Apparatus for decoding a coded digital signal, this coded signal resulting from an original digital signal decomposed into a plurality of subsignals, the subsignals being coded by means of a coding technique among a plurality of coding techniques, the apparatus comprising:

• applying means for applying a plurality of decoding techniques to a coded subsignal;
• and
• reading means for reading, from the stream of coded subsignals, an item of information making it possible to select a decoding technique among decoding techniques if at least two decoding techniques are acceptable.

A memory medium for storing a program to be executed in a digital signal coding apparatus, said program comprising:

• code for choosing a coding technique to code a plurality of subsignals obtained by dividing the digital signal among a plurality of coding techniques, so as to produce a stream of coded sugsignals,
• code for checking if the decoding of coded subsignals by at least two different decoding techniques associated to the coding techniques is acceptable, and
• code for inserting an item of information in the stream of coded subsignals making it possible to select, during decoding, a decoding technique associated with a coding technique used for coding said subsignal if at least the decoding of one coded subsignal by at least two different techniques is acceptable.

A memory medium for storing a program to be executed in a digital signal decoding apparatus for decoding a coded digital signal, the coded digital signal resulting from an original digital signal decomposed into a plurality of subsignals, at least one subsignal being coded by means of a coding technique among a plurality of coding techniques, said program comprising:

• code for applying a plurality of decoding techniques to at least one coded subsignal, and
• code for reading in the stream of coded subsignals an item of information making it possible to select a decoding technique among decoding techniques if at least two decoding techniques are acceptable for at least one coded subsignal.

A program stored in a memory medium in a digital signal coding apparatus, said program comprising:

• code for choosing a coding technique to code a plurality of subsignals obtained by dividing the digital signal among a plurality of coding techniques, so as to produce a stream of coded subsignals,
• code for checking if the decoding of coded subsignals by at least two different decoding techniques associated to the coding techniques is acceptable, and
• code for inserting an item of information in the stream of coded subsignals making it possible to select, during decoding, a decoding technique associated with a coding technique used for coding said subsignal if at least the decoding of one coded subsignal by at least two different techniques is acceptable.

A program stored in a memory medium in a digital signal decoding apparatus for decoding a coded digital signal, the coded digital resulting from an original digital signal decomposed into a plurality of subsignals, at least one subsignal being coded by means of a coding technique among a plurality of coding techniques, said program comprising:

• code for applying a plurality of decoding techniques to at least one coded subsignal, and
• code for reading in the stream of coded subsignals an item of information making it possible to select a decoding technique among decoding techniques if at least two decoding techniques are acceptable for at least one coded subsignal.

Apparatus for decoding a coded digital signal, the coded digital signal resulting from an original digital signal decomposed into a plurality of subsignals, at least one subsignal being coded by means of a coding technique among a plurality of coding techniques, the apparatus comprising:

• a processor for applying a plurality of decoding techniques to at least one coded subsignal, and
• for reading in the stream of coded subsignals an item of information making it possible to select a decoding technique among decoding techniques if at least two decoding techniques are acceptable for at least one coded subsignal.