RealAudio atrc

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Found in some old RealMedia files. The same as the ATRAC3.

Scrambling

In RealMedia files, the ATRAC3 bitstream is scrambled. To unscramble the stream, perform a XOR on every 32 bits in the frame. The hex value to XOR with is 0x537F6103.

Extra data format

In RealMedia files, ATRAC3 extra data has the following format (big-endian order):

INT32	id, always 4
INT16	samples per frame, always 1024 * 2
INT16	delay, not used but always 0x88E
INT16	stereo coding mode, 2 - normal stereo, 0x12 - joint stereo

The length of this data is always 10 bytes.