Method and device for flexible combined format bit-rate adaptation in an audio codec

A combined format encoder for coding a number of first audio object channels in ISM format and a number of second audio channels in immersive audio (IA) format, comprising:

• at least one processor;
• and
• a memory coupled to the processor and storing non-transitory instructions that when executed cause the processor to implement:
• an ISM format encoder comprising:
• a first front pre-processor of the audio object channels to produce ISM pre-processing parameters;
• and
• a first core-encoder section responsive to an adapted ISM total bit-rate for coding the audio object channels;
• and
• an IA format encoder responsive to an adapted IA total bit-rate for coding the second audio channels;
• and
• a device for combined format bit-rate adaptation using at least one ISM pre-processing parameter from the first front pre-processor for (a) adapting an initial ISM total bit-rate to produce the adapted ISM total bit-rate and (b) adapting an initial IA total bit-rate to produce the adapted IA total bit-rate.

A combined format method for encoding a number of first audio object channels in ISM format and a number of second audio channels in immersive audio (IA) format, comprising:

• ISM format encoding the audio object channels comprising:
• front pre-processing the audio object channels to produce ISM pre-processing parameters;
• and
• core-encoding the audio object channels in response to an adapted ISM total bit-rate;
• and
• IA format encoding the second audio channels in response to an adapted IA total bit-rate;
• and
• a combined format bit-rate adaptation using at least one ISM pre-processing parameters from the front pre-processing of the audio object channels for (a) adapting an initial ISM total bit-rate to produce the adapted ISM total bit-rate and (b) adapting an initial IA total bit-rate to produce the adapted IA total bit-rate.