fdkaac reads linear PCM audio in either WAV, raw PCM, or CAF format,
and encodes it into either M4A / AAC file.
If the input file is "-", data is read from stdin. Likewise, if the
output file is "-", data is written to stdout if one of streamable AAC
transport formats are selected by -f.
When CAF input and M4A output is used, tags in CAF file are copied into
the resulting M4A.