Mp4a.40.2 -140- Jun 2026

The final piece of the codec puzzle is . This number specifies the Audio Profile . In the MPEG-4 standard, profiles define the complexity of the audio tools used.

: Indicates the media belongs to the MPEG-4 audio family. 40 : Represents the MPEG-4 object type in decimal. 2 : Specifically identifies the Low-Complexity (LC) profile. mp4a.40.2 -140-

If you see mp4a.40.2 -140- in an error log, here is what likely went wrong. The final piece of the codec puzzle is

When in doubt, select format 140 . You will rarely be wrong. : Indicates the media belongs to the MPEG-4 audio family

AAC comes in various flavors, such as AAC-Main, AAC-SSR (Scalable Sampling Rate), and AAC-LD (Low Delay). AAC-LC is the "Goldilocks" profile. It provides high-quality audio at lower bitrates (like 128kbps or 192kbps) without the high computational demands of the "Main" profile. Because it strikes the perfect balance between file size, quality, and processing power, AAC-LC is the standard for Apple’s iTunes Store, YouTube, and most streaming services.