
test.m4a contains an AAC LC stream inside an M4A (MPEG-4 Part 14) container. It is generated by FFmpeg 3.1.3 from test.wav: ffmpeg -y -i test.wav -c:a aac -profile:a aac_low -b:a 32k test.m4a test.m4a facilitates testing utilities or libraries that work with the AAC codec or the M4A container, e.g., alac.