Comparing AAC vs MPEG

Norvan Martin
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This is a blog post describing the differences between MPEG and AAC, two popular encoding formats.

MPEG is a video file format for movies that are distributed on the internet. AAC is a part of MPEG format but AAC is just for audio and does a better job compressing the audio. While AAC is superior in terms of sound quality for a given file size, MPEG is still the preferred format for portable media players as these devices support playback of MPEG-compliant files like MP3 and MP4.

AAC vs MPEG Comparison Table

Compression EfficiencyHigh compression ratio, small file sizesVaries, consider compression ratio
Audio QualitySubjectively good qualityDepends on bit rate and implementation
CompatibilityWidely supported across devicesCheck compatibility with specific devices
Bit RatesConsistent performance across bit ratesPerformance varies with bit rate
Complexity of Encoding/DecodingMedium complexityVaries, can be complex
Use Cases and ApplicationsOptimized for various applicationsDepends on specific use cases
Licensing and Patent IssuesConsider licensing costsCheck for licensing and patents
Robustness in Error ConditionsGood error handlingVaries, check error resilience
Openness and StandardizationStandardized formatDepends on specific MPEG standard

You can check out other similar audio codec comparisons here:



MP3 320 vs FLAC

AAC vs MP4

What is AAC?

AAC is a standardized, lossy compression and encoding scheme for digital audio. AAC was created as a successor to MP3 files, but it includes several improvements over its predecessor.

The most noticeable development is that AAC uses “perceptual coding” instead of “entropy coding.” The psychoacoustic model used represents how helpful information is heard rather than what can be heard.

What is AAC

The difference between perceptual and linear coding techniques lies in how they handle masking effects. Linear coders are limited to processing signals within a specific bandwidth, while perceptual coders reproduce the signal over a broader range of frequencies.

AAC allows up to 48 channels (up to 8 discrete audio tracks) and supports a maximum sample rate of 96 kHz. AAC also includes 16-bit/44.1 kHz files and 24-bit/96 kHz high-resolution lossless audio support.

What is MPEG?

What is MPEG

MPEG stands for Moving Picture Experts Group.

It was formed in 1988 by organizations actively involved in creating standards for compression, decompression, processing, and coded representation of moving pictures and audio.

MPEG is not to be confused with MP3, which stands for the compression standard of music files. MP3 is an audio format while MPEG is a video format used in DVDs.

The MPEG encoding format for mp3s is used by millions of people worldwide to save space on their phones, tablets, or computers.

Typically if someone says they are using the MPEG codec or a MPEG file, they mean an MP3 file that uses the above coding system. The main advantage of the MPEG over other similar types of codec is that it uses a system known as perceptual coding.

This means that a fixed number is used instead of using a variable bit rate to express different amounts of data. In most cases, this is 128 kbps which means the audio only takes up about one-tenth of its original size with little noticeable loss in quality.

Why use AAC?

There are several benefits to using this format over others, including enhanced audio quality and better compression rates, translating into smaller file sizes.

Here Are The Reasons to Always Use AAC:

1. File Size Comparisons

It’s no big secret that file size matters, especially when talking about digital stuff. Using AAC encoding for mp3 conversion will usually result in smaller file sizes than their equivalent MP3 counterparts. This means less storage space is required, which most people would prefer.

2. Compatibility Concerns

Compatibility with different operating systems might also be a concern for you regarding digital stuff. Well, using AAC encoding for mp3s ensures that your files will be compatible with almost all modern operating systems, including Mac OSX and Linux.

3. Audio Quality Concerns

It’s a known fact that aac/m4a files produced by iTunes have more audio quality than regular MP3s. Using the AAC format ensures that you get the best output possible from your media player or mobile device.

4. Portability Concerns

Another BIG plus side to using Aacs is using them on almost any portable media player available on the market today.

Imagine being able to convert your favorite song into a high-quality AAC and put it in your pocket. That’s right, no more bulky, heavy MP3 players and inconveniently sized earbuds.

5. No Loss of Quality

What is good in having a file size smaller than its equivalent MP3 if we don’t get the same quality? Luckily for us, using AAC encoding doesn’t result in any loss of quality when compared to their MP3 counterparts. The AACs might sound better than their default format.

Why Use MPEG?

Why Use MPEG

MPEG encoding is an industry standard for digitally compressing and decompressing audio. MPEG compression is based on “psychoacoustic” (human perception of sound) to reduce the number of bits required to store or stream an audio file.

Here Are The Reasons To Always Use MPEG:

1. MP3 Has a High Compression Ratio

MPEG is a standard established by the International Organization for Standardization (ISO), and it describes how to compress video and audio data.

MPEG encoding format usually reduces file sizes dramatically compared to uncompressed sound formats such as WAV or AIFF, which contain “raw” PCM audio without any data reduction as you know that fewer data means a faster transfer rate.

There are many versions of this codec, but MPEG-1 Audio Layer 3, also known as MP3, is the most common due to its high compression efficiency and unique qualities.

2. High Quality at Low Bit Rates

According to the Nyquist Theorem, you can encode half of your sample rate to reproduce information that is lower than the original quality.

MPEG encoding format uses this theorem to reduce file size. However, sometimes if we use low bit rates, it does not sound so good.

That’s why MPEG comes with many predefined bit rates (48/56/64/80/96/112/128) and 3 fine-tuning parameters for custom bit rates (Q factor, pre-emphasis, and cutoff frequency).

Depending on these factors, you can achieve very high or lousy quality. Some people might say that at a 128kb bit rate, MP3 recording sounds like FM radio, but in fact, it is their lack of knowledge about how these parameters work.

3. The MPEG Encoding Format is Compatible With Most Portable Audio Players

Almost all of the newer portable music players support this codec. There are also hardware decoders that can listen to MP3 files on legacy devices or anywhere else where you cannot install the software (e.g., in some cars).

4. The Best Sound Quality at Low Bit Rates

When you encode a song from WAV format to 192kb/s bit rate, it might not sound better than the original, which means no information has been added.

However, if we do it in the MPEG encoder, then at lower bit rates, there will be more detail in the result compared to the input because of psychoacoustic techniques that have been implemented in it.

5. MPEG Encoding Format Works Great for Voice and Other Mono Recordings

This is because of the psychoacoustic model implemented in the MPEG encoder, which suppresses information about sounds that we cannot hear (e.g., Downloaded ringtones).

Anyways, if you encode a stereo sound file to MP3, it will automatically be converted to mono.

Pros of AAC

  • AAC uses less file size than other encoding formats
  • AAC has more efficient compression compared with MP3
  • Both encoding and decoding are faster with AAC
  • Support for High Bit Rate (HBR) Audio
  • Better Supported by Apple Products
  • Better output quality on low bit rates

Cons of AAC

  • The sound quality might be poor
  • Your device might have trouble playing back certain files

Pros of MPEG

  • Savings on space and file size: The choice to go with a MPEG-based codec over other formats will often save significant space and file size.
  • Save on energy costs: If you work in a business environment where power consumption is closely monitored and controlled, it’s probably best to use MPEG video instead of AVCHD or other formats. This can quickly shoot up your electricity bill.
  • Easy to work with: As you’ll find out as we go through the pros, a MPEG-based codec will be much easier to work with compared to others.
  • Quick sharing: If you want your footage to be adopted quickly and used by a wider audience, then using a MPEG-based codec is your best option. This is because their popularity is well known in practically all countries around the globe, regardless of language barriers.
  • Interoperability: MPEG-based codecs are a staple in the video production industry, so naturally, it’s only natural that they have been adopted by practically all other major tech companies. This means their tech can easily interoperate with each other, as well as third-party techs such as hardware and software decoders.
  • You may already own one: If you’re using an HDV camcorder, then the chances are that its native format is going to be MPEG2. This makes sense since AVI was also standard before the advent of DVCPRO HD/ AVCHD/ MPEG-2.

Cons of MPEG

  • MPEG is not free to use and implement as there are patents that must be paid for their usage
  • The license costs depend on how many products you plan on selling that will use a MPEG encoded file


It may seem obvious, but the main difference between AAC and MPEG encoding formats is that aac is a newer format designed to be used for lossy encoding. In addition, you can check out our article on AAC vs MPEG for youtube.

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Norvan Martin is the founder of He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin