Audio format defines the quality and loss of audio data. Based on application different type of audio format are used. Audio formats are broadly divided into three parts:
- Uncompressed Format
- Lossy Compressed format
- Lossless Compressed Format
1. Uncompressed Audio Format:
- PCM –
It stands for Pulse-Code Modulation. It represents raw analog audio signals in digital form. To convert analog signal into digital signal it has to be recorded at a particular interval. Hence it has sampling rate and bit rate (bits used to represent each sample). It a exact representation of the analog sound and do not involve compression. It is the most common audio format used in CDs and DVDs
- WAV –
It stands for Waveform Audio File Format, it was developed by Microsoft and IBM in 1991. It is just a Windows container for audio formats. That means that a WAV file can contain compressed audio. Most WAV files contain uncompressed audio in PCM format. It is just a wrapper. It is compatible with both Windows and Mac.
- AIFF –
It stands for Audio Interchange File Format. It was developed by Apple for Mac systems in 1988. Like WAV files, AIFF files can contain multiple kinds of audio. It contain uncompressed audio in PCM format. It is just a wrapper for the PCM encoding. It is compatible with both Windows and Mac.
2. Lossy Compressed Format:
It is a form of compression that loses data during the compression process. But difference in quality no noticeable to hear.
- MP3 –
It stands for MPEG-1 Audio Layer 3. It was released in 1993 and became popular. It is most popular audio format for music files. Main aim of MP3 is to remove all those sounds which not hearable or less noticeable by humans ears. Hence making size of music file small. MP3 is like universal format which is compatible almost every device.
- AAC –
It stands for Advanced Audio Coding. It was developed in 1997 after MP3.The compression algorithm used by AAC is much more complex and advanced than MP3, so when compared a particular audio file in MP3 and AAC formats at the same bitrate, the AAC one will generally have better sound quality. It is the standard audio compression method used by YouTube, Android, iOS, iTunes, and PlayStations.
- WMA –
It stands for Windows Media Audio. It was released in 1999.It was designed to remove some of the flaws of MP3 compression method. In terms of quality it is better than MP3. But is not widely used.
3. Lossless compression:
This method reduces file size without any loss in quality. But is not as good as lossy compression as the size of file compressed to lossy compression is 2 and 3 times more.
- FLAC –
It stands for Free Lossless Audio Codec. It can compress a source file by up to 50% without losing data. It is most popular in its category and is open-source.
- ALAC –
It stands for Apple Lossless Audio Codec. It was launched in 2004 and became free after 2011. It was developed by Apple.
- WMA –
It stands for Windows Media Audio. But it is least efficient in term of compression and is not open-source. It has limited hardware support.