Windows isn't for everybody, so here's the Unix-compatible version of a tool I consider very important. Enjoy!
This is a command line tool intended to convert audio into a lossless encoding of the Nintendo AST format found in games such as Super Mario Galaxy and Mario Kart: Double Dash. The resulting audio file is also compatible with lossy interpretations of AST as seen in The Legend of Zelda: Twilight Princess.
Usage: ./ASTCreate <input file> [optional arguments]
OPTIONAL ARGUMENTS
-o [output file] (default: same as input minus extension)
-s [loop start sample] (default: 0)
-t [loop start in microseconds] (ex: 30000000 would be the equivalent of 30 seconds, or 960000 samples with a sample rate of 32000 Hz)
-n (disables looping)
-e [loop end sample / total samples] (default: number of samples in source file)
-f [loop end in microseconds / total time]
-r [sample rate] (default: same as source file / argument intended to change speed of audio rather than size)
-h (shows help text)
USAGE EXAMPLES
./ASTCreate inputfile.wav -o outputfile.ast -s 158462 -e 7485124
./ASTCreate "use quotations if filename contains spaces.wav" -n -f 95000000
Note: This program will only work with WAV files (.wav) encoded with 16-bit PCM. If the source file is anything other than a WAV file, please make a separate conversion first. Also please ensure the input/output filenames do not contain Unicode characters.