* fixed#16938: Audio could not be played entirely on iOS/macOS. And refactored some code of decoding.
* Adds license header, removes unused macros.
* issue #16938: Corrects remaining frame count calculation.
* Updates include path.
* Adds comments for AudioDecoder class.
* Adds const for getter functions in AudioDecoder.
* issue #16938: Adds test case.
* Updates license years.
* Deletes trailing white spaces.
James Chen