Both Mp3 and AAC are setups for audio files. Mp3 (MPEG-1 Audio Layer III /MPEG-2 Audio Layer III) and AAC (Advanced Audio Coding) are coding formats used for digital audio.
AAC was designed to be the successor of mp3 with more improvements and higher efficiency but the sound quality of both the audio files is almost the same.
MP3 vs AAC
The main difference between Mp3 and AAC is their sample frequencies with Mp3 having 16kHz to 48kHz frequency and AAC having 8kHz to 96kHz frequency.
Mp3 is basically a standard technology that uses a format to compress a sound into the around one-twelfth size of an original file while keeping the original level of the sound quality preserved.
AAC can be used to code audio files from minimum to high bit rates. AAC is built as a successor of Mp3 with more effective and efficient sound quality.
Also, AAC has up to 48 channels whereas MPEG-1 mode has 2 channels and MPEG-2 has around 5.1 channels only.
Comparison Table Between Mp3 and AAC
| Parameters of Comparison | MP3 | AAC |
| File extension | It uses .mp3 as an extension. | It uses .m4p, .m4a, .m4b, .mp4, .acc as an extension. |
| Quality | Mp3 offers a lower voice quality than AAC and the same bitrate | AAC offers a better voice quality although it gives a very loose compression |
| Popularity | Mp3 is available on all devices | AAC is popular among iPod and iPhone but not as popular as mp3 |
| Release | 1994 | 1997 |
| Frequency | 16 kHz – 48 kHz | 8 kHz – 96 kHz |
What is Mp3?
Mp3 (MPEG-1 Audio Layer III) is digital audio that was developed by Fraunhofer Society (Germany) using some help from the scientist in the US. Mp3 uses a lossy data compression (in regard to audio compressions) to encode data. Mp3 is famous because of its ability to compress files and making it convenient to store music.
Basically 4 parts describe the Mp3 algorithm
- Breaks the audio system into smaller pieces (called frames)
- Passes the sample into a 1024-point FFT (Fast Fourier transform)
- It then Counts and encodes each sample (known as noise allocation)
- Formats the bitstreams.
The encoder algorithm and bitrate are also terms on which the quality of sound that’s encoded by mp3 depend on. The quality of sound mostly depends on the encoding parameters.
The mp3 coding technology is basically patent-free as all the patents have expired latest by 2012. Mp3 supports only up to 2 channels in MPEG-1 mode and up to 5.1 channels in MPEG-2 mode. Mp3 handles a frequency of 16 kHz to 48 kHz.
What is AAC?
Advanced audio coding is a successor for mp3 with more efficient audio quality and having a higher frequency sound which is 8 kHz to 96 kHz. AAC achieves a higher sound quality than mp3 at the same bit rate. AAC composes of 48 full-bandwidth channels of 96 kHz. AAC Is also a default standard audio format for iPhones, iPods, etc.
The major improvements that AAC has over mp3 are as follows.
- It has more sample rate.
- More channels of high bandwidth (48)
- Higher coding efficiency
- More flexible i.e., various methods can be used for various frequency ranges
- Additional tools.
AAC has a firm industry support and hence is a strong contender.
AAC is an international standard which a lot of companies have kept in use for example Dolby company Inc, Sony Corp., and Nokia Corp.
Although still, not all devices use AAC. Mostly all iTunes and iPods have given access to AAC audio format
Main Differences Between Mp3 and AAC
- The main difference between AAC and Mp3 is the frequency that the two use. While AAC uses a frequency of 8 kHz to 96 kHz, Mp3 uses only 16 kHz to 48 kHz.
- The number of channels that are present in AAC is 48 wherein Mp3 mode MPEG-1 has only 2 channels and MPEG-2 mode has around 5.1 channels.
- The length of the block of both the audio formats also varies a lot. AAC uses a block size of 1024 (or 960 samples) and Mp3 uses a block size equivalent to 560 samples.
- Mp3 has a file extension of .mp3 whereas AAC has extensions like .m4a, .m4b, .m4p, .m4v, .m4r, .mp4, .aac.
- Both the audio files use a different MIME type (Multipurpose Internet Mail Extensions). AAC uses audio/aac, audio/aacp, audio/3gpp, audio/3gpp2, audio/mp4, etc. Mp3 on the other hand uses audio/MPEG as its MIME-type
Conclusion
Mp3 and AAC are two formats of audio files. AAC is a successor of mp3 which was built with higher efficiency and better quality of sound. AAC reduces the file size without compromising the sound quality and also uses a higher frequency to get better results. Mp3 is available on all devices, unlike AAC which is available only on iPods and iTunes.
AAC requires a file size of 6.7 MB at an encoding rate of 192 K while Mp3 requires a file size of 3.9 MB at an encoding rate of 128 K.
There are differences in sound files of both the audio formats but they seem pretty similar on hearing and hence the difference between the two cannot be differentiated.
Mp3 is an older file format and hence compared to AAC it does not have a small file or better sound quality but the biggest advantage it carries is that it is accepted and available on all devices (portable or non-portable). iTunes can be used to convert any AAC file to Mp3 format if any device doesn’t support AAC. AAC will sound better at high frequencies while Mp3 sounds better at low frequency. As AAC is about 2- generations younger than Mp3, the file formats have definitely improved from that time – hence apple opted for AAC as a file format for iTunes. Converting Mp3 to AAC audio format may deteriorate the sound quality and make it less effective for use.
References
- http://www.aes.org/e-lib/browse.cfm?elib=8079
- http://pop-sheet-music.com/Files/6102addd569a352211564c52aefd5040.pdf