Saturalabs original M4A conversion test

stereo-test.m4a: synthesized 3-second AAC recording, 48 kHz stereo,
49,438 bytes. Left: 440 Hz sine; right: 880 Hz sine. Source amplitude
0.12, with 20 ms fade-in and fade-out. No speech or music performance.
AAC encoding and browser decoding can change samples and frame counts.
This file is not a benchmark of speech/music fidelity or universal codec support.

Generated with FFmpeg:
ffmpeg -v error -f lavfi -i 'aevalsrc=0.12*sin(2*PI*440*t)|0.12*sin(2*PI*880*t):s=48000:d=3' -af 'afade=t=in:d=0.02,afade=t=out:st=2.98:d=0.02' -c:a aac -b:a 128k -movflags +faststart -map_metadata -1 stereo-test.m4a
Encoder versions may produce different bytes.

To the extent possible under law, Saturalabs dedicates this original synthetic
stereo-test.m4a and these notes to the public domain under CC0 1.0:
https://creativecommons.org/publicdomain/zero/1.0/
This dedication applies only to this example, not other site media or user files.