Initialize the specified channel map for the specified number of
* channels using default labels and return a pointer to it. This call
* will fail (return NULL) if there is no default channel map known for this
* specific number of channels and mapping.
Initialize the specified channel map for the specified number of * channels using default labels and return a pointer to it. This call * will fail (return NULL) if there is no default channel map known for this * specific number of channels and mapping.