Digital Audio File Formats - Lossy Vs. Lossless
There are a variety of digital audio file formats. Most people are familiar with the mp3 but there are many others - some made for music and others with just speech in mind. There are two main types you should know about: lossless and lossy. Lossless are higher quality and include wav files. Lossless files throw out a lot of the audio data in order to reduce the total size. The best example is the mp3.
Not all digital audio is the same however; not only can it be found in variable compression formats but because we deal in so many different types of technology and how that data is read, there are numerous digital audio formats.
Those digital audio formats, also referred to as codecs (MP3, WMA, AAC, AIFF, etc.) are grouped into two different categories; Lossless and Lossy. Regardless of where it's grouped however, a codec is named such because of its overall function. Codec= compression + decompression of music into digital audio files.
Working with Lossless Codecs
With Lossless Codecs, every bit of the musical data and information that forms the overall audio file is maintained and preserved upon compression. That data is then stored for retrieval. When compared to other audio, lossless codecs offers up the highest audio fidelity with the crispest digital sound.
The unfortunate downside is that the files they create can become expansive and rather large. Depending on the size of your music server or drive, you could be limited with the number of songs you can store. As technology continues to advance however this is becoming less of an issue. Terabyte external drives and small portable drives and players exceeding 500 gigabytes will have little problem with storage capacity.
The most common Lossless Codecs:
Windows Media Lossless - this codec is built into newer versions of Windows Media Player software from Microsoft and is widely supported by a number of other media adapter systems.
Apple Lossless - Of course Microsoft has its competitor in Apple. This codec is included in the iTunes software and the Apple Lossless Encoder is their answer to the Windows Media Lossless.
Free Lossless Audio codec (FLAC) - Wherever there is something commercial there can often be found something free. As the name implies the FLAC is a codec that is free on the digital market. It's widely supported, and a few of the audio players that support the free codec includes the Sonos Digital Music System and Slim Devices (of course there are numerous others).
Working with Lossy Codecs:
When you're dealing with data compression, you can expect some loss of data. Lossy codecs discard some of the music information intentionally in order to reduce the size of the audio file. This is done for a variety of reasons including the reduction of overall size in order to allow more digital files to be stored. Likewise, size reduction makes it easy to move files over the web. To the human ear, listening to the music on a run of the mill audio system won't reveal much difference. If you play the sound through a quality sound or home theater system you can begin to pick up the subtle difference in quality and tone.
The most common Lossy Codecs:
MP3 - Also known as MPEG-1 Audio Layer 3 (Motion Picture Experts Group). As the concept of digital music grew, it was the mp3 that took over as the preferred format due to the great compression ratio. Because of its widespread acceptance, it's the most common digital music codec on PC's and digital music systems. Most equipment including Compact Disc players and digital file recorders/players are designed to read this codec. Proof is in the fact that most people refer to portable music devices "Mp3 players".
WMA - Windows Media Audio is the standard audio format used on the Windows operating system and Windows Media Player as well as compatible hardware. While it's possible to use a lossless version of WMA, most files use and rely on lossy compression systems.
AAC - While most audio formats can be read across different systems, even Mac, Apple Computers iTunes Store uses the Advanced Audio Codec (AAC) as the default codec for music that's been encoded using the iTunes app. Like Windows Media Audio, AAC files fall under the Lossy category. You can however access a lossless codec within the iTunes system known as Apple Lossless.
Other Common Formats
WAV files were a common format among PC users in the 90's and are still a widely used format. The quality of a .wav file is equivalent to that of a Compact Disc and is used by many audio professionals when recording and editing music. The downside is that .wav files are lossless and as such the files are very large in size. A .wav file is about 10 megabytes for every minute of audio, making it a poor choice when storing many songs on a small capacity audio player.
Like .wav files popular for PC users, the .aiff format is a popular lossless format for the Apple user. The format was developed by Apple in 1988 in conjunction with Electronic Arts and was widely used on the Amiga systems and Mac computers. Like .wav files, standard .aiff is used on the professional level with audio and video apps and, like .wav files, it is uncompressed leading to large files.
Choosing a codec
Which codec you ultimately choose depends on a few factors including where you get your music, the device you play your music on and of course your personal preference. Although most stores sold WMA and AAC formats because of the ability to digitally protect the files with DRM (digital rights management) encoding. most stores nowadays have switched to the more generic MP3 audio file. MP3 files are not protected but are generally lesser quality files.
If you have a high quality sound system with high storage capacity you'll likely enjoy the fidelity offered by lossless codecs. If you pipe music through your stereo system from a computer you'll need to give some consideration to the software you use, as many have a limited number of supported codecs.
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Audible Forensics provides both forensic audio and audio transfer services. Our clients include law enforcement agencies, businesses, universities, museums, and others. Visit our website if you’re interested in these services: Voicemail Retrieval, Convert Cassette Tape to CD or mp3, Transfer Reel to Reel to CD or mp3.