Delayed packet concealment method and apparatus

A decoding method in a packet network that uses delayed frame parameters to improve concealment of delayed packets, said method including the steps:

• saving a copy of a correct initial decoder state in case of packet delay;
• producing a first decoded output signal by using an erroneous initial decoder state obtained from concealment of at least one delayed packet and a set of frame parameters;
• decoding delayed packets using said saved initial decoder state in order to update said saved initial decoder state;
• producing a second decoded output signal based on said updated initial decoder state and said set of frame parameters;
• and
• combining said first and second output signals.

A delayed packet concealment apparatus in a packet network that uses delayed frame parameters to improve concealment of delayed packets, said apparatus including:

• means for saving a copy of an initial decoder state that existed after decoding the last non-delayed packet;
• means for decoding and concealing packet delay by using predicted frame parameters and said initial decoder state, thereby producing an erroneous initial decoder state;
• means for decoding by using updated frame parameters from said delayed packet and said saved initial decoder state, thereby producing a corrected initial decoder state;
• means for decoding by using a set of frame parameters and said erroneous initial decoder state, thereby producing a first output signal and a further erroneous initial decoder state;
• means for decoding by using said set of frame parameters and said corrected initial decoder state, thereby producing a second output signal;
• and
• means for combining said first and second output signals.

A decoder in a packet network that uses delayed frame parameters to improve concealment of delayed packets, said decoder including:

• a memory for saving a copy of a correct initial decoder state in case of packet delay;
• a first decoder section for producing a first decoded output signal by using an erroneous initial decoder state obtained from concealment of at least one delayed packet and a set of frame parameters;
• a second decoder section used for decoding delayed packets using said saved initial decoder state in order to update said saved initial decoder state, and for producing a second decoded output signal based on said updated initial decoder state and said set of frame parameters;
• and
• means for combining said first and second output signals.