Browse Definitions :
File Extension

M4A File Format

Unprotected AAC audio file

M4A file format icon

M4A is a file extension for an audio file encoded with advanced audio coding (AAC) which is a lossy compression. M4A was generally intended as the successor to MP3, which had not been originally designed for audio only but was layer III in an MPEG 1 or 2 video files. M4A stands for MPEG 4 Audio.

Both M4A and MP3 file extensions are used for audio-only files. Audio-only MPEG 4 container files usually have an M4A file extension. M4A files are unprotected. Protected files usually have an M4P file extension.

AAC or M4A file quality is better and file sizes smaller compared to MP3 files. M4A files sound better than MP3 files when encoded at the same bit rate due to some of the enhancements made to the format such as:

  • Compression based on perception -- if it is not within human perception, that sound data may be lost without notable effect to quality.
  • Smaller sample block size of 120 or 128 samples rather than 192 for changing (or transient) signals, allowing for more precise details where they are needed.
  • Larger block sizes in stationary signals, 1024 or 960 vs MP3's 576 sample blocks, allowing for less data to represent a portion of the music that does not have the same complexity.

Programs that open M4A files include iTunes, Quicktime, Windows Media Player, and Roxio Popcorn, Toast and Creator. Some media players will only play the format when renamed to MP4.

 

Learn more about M4A-related files:

Andoni Oconchubhair defines MPEG standards at Search SOA

Look for answers to M4A-related questions on IT Knowledge Exchange.

Visit the MPEG webpage.

This was last updated in August 2010
Browse File Extensions Alphabetically:

Join the conversation

2 comments

Send me notifications when other members comment.

Please create a username to comment.

AIMP3 can open m4a too and don't forget VLC
Cancel
I have a huge collection of .m4a music files. In one of my vehicles I have a bus accessory for the head unit that will play back music on a thumb drive. On one of my other vehicles the head unit was installed in 2003 and has a bus input (Alpine 7998 Phantom) and I'm looking for a (?) small personal player, computer pad, etc. that will play back .m4a files. Most will tell you if they play back AAC files, but not specifically .m4a. I can find high quality Ai bus accessories that have stereo or 3.5 mm connectors. Every high-rez unit I look at has too many complaints about loading or using the file system. This is an area that is being overlooked by the stereo manufacturers.
Cancel

-ADS BY GOOGLE

SearchCompliance

  • regulatory compliance

    Regulatory compliance is an organization's adherence to laws, regulations, guidelines and specifications relevant to its business...

  • privacy compliance

    Privacy compliance is a company's accordance with established personal information protection guidelines, specifications or ...

  • data governance policy

    A data governance policy is a documented set of guidelines for ensuring that an organization's data and information assets are ...

SearchSecurity

SearchHealthIT

  • telemedicine (telehealth)

    Telemedicine is the remote delivery of healthcare services, such as health assessments or consultations, over the ...

  • Project Nightingale

    Project Nightingale is a controversial partnership between Google and Ascension, the second largest health system in the United ...

  • medical practice management (MPM) software

    Medical practice management (MPM) software is a collection of computerized services used by healthcare professionals and ...

SearchDisasterRecovery

  • disaster recovery (DR) test

    A disaster recovery test (DR test) is the examination of each step in a disaster recovery plan as outlined in an organization's ...

  • crisis management plan (CMP)

    A crisis management plan (CMP) is a document that outlines the processes an organization will use to respond to a critical ...

  • pandemic plan

    A pandemic plan is a documented strategy for business continuity in the event of a widespread outbreak of a dangerous infectious ...

SearchStorage

  • megabytes per second (MBps)

    Megabytes per second (MBps) is a unit of measurement for data transfer speed to and from a computer storage device.

  • zettabyte

    A zettabyte is a unit of measurement used by technology professionals and the general public to describe a computer or other ...

  • hybrid flash array

    A hybrid flash array is a solid-state storage system that contains a mix of flash memory drives and hard disk drives.

Close