codecUtilsAacGetLevel

fnstring codecUtilsAacGetLevel(ubyte[] audioConfig)

Determines the level of a stream as defined in ISO/IEC 14496-3. For AAC LC streams, the constraints from the AAC audio profile are applied. For AAC Main, LTP, SSR and others, the Main profile is used.

The audio_config parameter follows the following format, starting from the most significant bit of the first byte:

  • Bit 0:4 contains the AudioObjectType (if this is 0x5, then the

real AudioObjectType is carried after the rate and channel data)

  • Bit 5:8 contains the sample frequency index (if this is 0xf, then the

next 24 bits define the actual sample frequency, and subsequent fields are appropriately shifted).

  • Bit 9:12 contains the channel configuration

Parameters

audioConfiga pointer to the AudioSpecificConfig as specified in the Elementary Stream Descriptor (esds) in ISO/IEC 14496-1.

Returns

The level as a const string and null if the level could not be

determined.