Latest version of FFmpeg encodes non standard channel layout, e.g. 5.1(side), in AAC using PCE.
This is now supported with the below changes:
- Allow channel_configuration in ADTS header to be 0, as the cctual channel layout is specified
in PCE.
- Add GetFrameSizeWithoutParsing to determine the frame size before actually parsing the frame.
- Skip and resume later if not the whole frame is available.
- Also ensure that the next frame starts with a proper sync word.
Fixes#598.