What do all the different audio formats mean and what do I do if my computer wont Run a file? There are many different types of audio formats that have developed over the years as technology has transitioned among many different standards. At this point in time, we are confronted with 6 common formats: WAV, MP3, AAC, AIFF, RA, and WMA (many of which come in protected and unprotected versions). WAV- This was one of the first formats of digital music but was quickly replaced as downloading increased in popularity. WAV files are very large and take a while to transfer. This is the type of file that is created by Window's Sound Recorder and can be manipulated rather easily with software. MP3- MP3s are the most popular digital audio files mainly for their compression capabilities. MP3s are very small files when compared to a WAV file and still maintain high quality sound. There are many different compression rates which affect the overall recording of the song but anything above 128 kbit/s is going to be pretty good quality. AAC- This format is equivalent to an MP3 however some would say it offers better quality. You can get the same quality sound out of 96 kbit/s AAC as you can with a 128 kbit/s MP3. This allows AAC files to be just a little smaller than MP3s and still have just as good of quality. AAC has recently become popular with the addition of iTunes to the digital music market. iTunes music comes in the AAC format and Apple's iPod is the only audio player that can play this file format. AIFF- An AIFF file is a Mac's version of a WAV file. They tend to be larger files used to store audio data. RA- This file type is most widely used for streaming audio. It can only be played on RealPlayer (free software) as well as other products from RealNetworks. The quality of a RA file is not as good as, say, an MP3 because it is intended to be streamed and therefore needs to be lower quality so there aren't any transmission problems. WMA- Short for Windows Media Audio, this is the file format commonly created by Windows Media Player. It is a compressible audio format that is ideal for streaming and downloading. They are smaller than MP3s and have about the same sound quality. More and more audio players are able to play WMA files but its use is not widespread. For a more side-by-side comparison of the different formats, Check out This Site. Although it hasn't been updated since 2002, the information is helpful to understand the difference between all the formats. As far as protected and unprotected formats go, these stem from the recent addition of online music stores. Now, whenever you download music from iTunes, Napster or any other online music source, the files are protected so that you can only play them on a certain number of machines or MP3 players. This was part of their agreement with the Recording industry so that they could actually sell the music online. If you were to copy a CD onto your computer, these files would most likely be unprotected and allow you to transfer them from computer to computer (although it is only legal on your computers!!). many of the files you download from the internet are protected and therefore might restrict the programs you can use to play them. If you know which program downloaded the song, the best option is to burn it to an audio disc through that program and then rip it back onto your computer as an unprotected copy. Another option would be to convert the file to a format that you can actually play (if it is protected, more than likely you can't do this). There isn't a universal converter available but This Converter seems to cover most formats. Finally, whenever you open a file whose format your computer does not recognize, the computer will prompt you to either 1) choose from a list of possible programs to open it with or 2) connect to the internet and find out what type of file it is. The internet will normally tell you what program created the file and might even offer a plugin (or codec) to use so that you can play the file. Windows Media Player will also prompt you sometimes to download a codec (information the program uses to play the file) and install it to play a certain file. If worse comes to worse, Google will usually return some helpful results.