Playing back digital audio has turned into a regular experience for most computer users thanks in part to a variety of formats that helped make audio smaller in size, allowing simple methods of digital distribution. There are many different formats that serve many different purposes. Need to know FLAC from MP3? We've broken down each format and its main purpose in this audio formats primer.
MP3
The most popular audio format, and the one that largely changed music as we know it, is called MP3. MP3 is a relatively old format and part of the first set of MPEG specifications governing the playback of both audio and video. MP3 actually stands for MPEG1 layer 3, and because of the name some people often confuse it with the audio/video standards MPEG-2 and MPEG-4.
MP3 is a lossy codec, which means when files are encoded to MP3, the encoder chooses which parts of the audio are most important, and discards other less important parts. This process results in audio files that are passable, but less complete than the original file. Depending on the bitrate at which the file is encoded, more information can be kept or thrown out. This "lossy" nature, like all MPEG codecs, makes it an ideal candidate as a delivery format, meaning a format for mass consumption, rather than an archival format. MP3 doesn't have any sort of digital rights management (DRM) built-in, meaning most MP3s can be transferred to any device and be expected to play.
AAC
MP3's ideal successor is AAC, which stands for Advanced Audio Codec. AAC was largely designed to be the next version of MP3, and accomplishes things like better quality audio at similar bitrates. That means AAC will sound better than similarly sized MP3s. While AAC might be the successor to MP3, thanks to MP3's 10+ year lifespan as a file format, MP3 is supported with most devices whereas AAC doesn't have the breadth of support in hardware devices by comparison. However, that's not to imply that AAC doesn't have a broad install base. Most notably, iPods can play AAC files back natively, and every track purchased in the iTunes Music Store is an AAC file.
Unlike MP3, AAC has seen some DRM implementations, again most notably in the iTunes Music Store. While not defined as part of the AAC specification, Apple has forked AAC to try to thwart music copying. The implementation, known as FairPlay, requires listeners to be using iTunes, and have a computer authorized to play the music before being able to actually listen to the files. Apple limits the computer count to five total activated iTunes accounts at a time (check out our guide to deauthorizing all those iTunes accounts at once if you ever hit your limit and find the need).
OGG
Another lossy audio format is the OGG format. OGG is a "free" format, meaning the format is maintained by the not-for-profit Xiph.org foundation, and doesn't charge for licensing or implementation. OGG is a file format popular with open source computer users, since there is no corporation sponsoring the format and all of the format's specifications and encoding methods are open and public. OGG is a less popular format, one not sanctioned by any store selling legal tracks, however many users transcode their music collections into OGG typically using the compression format called Vorbis. OGG files do not typically have any implementation of DRM, since the idea of DRM is counterintuitive to the nature of open source.
WMA
One format known most notably for its wide variety of DRM implementations is WMA, short for Windows Media Audio. WMA was created by Microsoft, likely as a response to the rise of other lossy codecs like MP3. WMA's main use is in subscription and pay-per-download music services. Microsoft created WMA to have wide copy protection measures in the files, seemingly to lure music industry labels to its side and make money off of licensing fees. Music services like Wal-Mart's online store, as well as Napster and Yahoo!'s music store all use WMA audio, with Napster utilizing a subscription model, and the other two utilizing a purchased downloads model.
The actual WMA codec consists of four sub codecs. The original WMA codec is the lossy codec that competes with MP3. WMA Pro is an audio codec that has extended support for multi-channel audio, and also works with higher resolution audio. WMA Voice targets voice-only content and works at much lower bitrates by constraining the encoder to vocal frequencies only. Lastly, WMA Lossless is a lossless codec, meaning the complete data from the original master is maintained; however, the audio is compressed to allow ease of transfer.
FLAC
Another lossless audio codec is the Free Lossless Audio Codec, commonly referred to as FLAC. FLAC is popular with the audio enthusiast scene, as the files created are smaller than WAV files, though the files still maintain all the audio fidelity of a WAV file. FLAC files can also be paired with "cue sheets" that define individual tracks inside of one larger FLAC file. FLAC files cannot be played back with most portable audio hardware, requiring either modified iPod firmware or custom portable players, but several notable players support it such as several in the Cowon line (including the Cowon A3, and iAUDIO 7) as well as the iriver SPINN, the SanDisk Sansa slotMusic player, and a number of Samsung PMPs including the YP-S2. FLAC's other primary advantage is that it is free, and any device manufacturer can implement FLAC at no charge. If you're looking for components to handle your FLAC collection, an updated list of many of the devices that support FLAC is kept at Sourceforge.
ALAC
One lossless format implemented on the most popular portable media player, the iPod, is the Apple Lossless Audio Codec (ALAC). ALAC allows users to take audio straight from CDs, convert it in iTunes to ALAC, and play it back in full fidelity on an iPod. ALAC files can only be played in Apple's music ecosystem (iTunes, Quicktime and iPod) and therefore the format is mainly suitable for audiophiles who enjoy listening to lossless music on an iPod exclusively.
WAV and AIFF
Most lossless audio comes from an originating source that has a bit-by-bit file that actually maps all the points on a sound wave. The two main formats of choice for complete recording are WAV (pronounced wave) and AIFF (sometimes pronounced "Aee-ph"). Both file formats are devoid of any sort of compression, making an average pop music song three or four minutes in length a hefty 50MB. While not as large of an issue in modern computing, 50MB file sizes in the mid to late 90s made the transfer of audio files extremely difficult, which is why lossy codecs were born. WAV is typically the Windows standard for audio storage, while AIFF is the Mac standard, though in modern usage both work interchangeably on either operating system. The WAV and AIFF formats are typically seen as "master" or "archive" formats, meaning they aren't typically distributed to the public since the file sizes are large, though the audio quality is much higher than any lossy codec.
Close cousin: MIDI
Lastly, one format that isn't specifically an audio format but should likely be mentioned is MIDI. Short for Musical Instrument Digital Interface, MIDI files don't actually contain any audio data, but rather contain references to timing and volume of notes, which can be interpreted by any MIDI capable device. Before MP3 took its throne as the format du jour of music pirates, MIDI files would be swapped around the internet in the same way that MP3s are traded. MIDI files are extremely small, often ranging in size from eight kilobytes up to a few dozen kilobytes on the "large" end.
Hopefully you're up to speed on audio formats now, and know which one to use for each project. If you've got any questions about any of the formats, be sure to sound off in the comments. If you've got an idea you'd like demystified, be sure to get in touch with us at on our tips form; we're happy to answer any tech questions you may have.
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Comments (41)
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Mat Bitner (5:18 PM on Fri Nov 7, 2008)
I hate it when people brag that they ONLY listen to their music in WAV, ALAC or FLAC formats to "preserve the quality," but listen to their music using Apple's default earbuds. Oh, the smugness! I'm as much an audiophile as anyone, and until you get some shure, klipsh, or certain bose or sennheiser headphones or earbuds, typically in the $300 + range, you can't tell the difference between the audio quality of simple 128 kpbs music files to any uncompressed files. It also depends on your player, though, not nearly as much as the hardware you put on/in your ears.
Just so you know, I think iTunes is pretty horrible at ripping music, in almost any format...that's my biased opinion anyway.
Stephen Schenck (2:41 AM on Sat Nov 8, 2008)
What do you think about Grados? I'm in love with my SR60s, but have been thinking about trading up to SR80s. Are the +$300 models THAT much better?
Mattia Fiumara (4:52 PM on Fri Mar 6, 2009)
You can tell the difference between 128 kbps and 320 with headphone from €60. You're talking about people bragging about listening to wav / flac to "preserve te quality", while you're bragging yourself about your 300 dolllar headphones.
Brian (6:29 AM on Tue Mar 10, 2009)
I have a pair of Grado Lab's SR60's and Sr 125's
The 125's are noticeable better but the the sr60's are still incredible and one hell of a deal, I have
also auditioned SR1's and SR2's and they both are noticeably better than my sr 125's so yes, there is a clear difference, but the difference between, the 60's and 80's is pretty minimal. Just as the difference between the SR1's and SR2's is similarly minimal. That being said the difference between the SR2's and my 125's is huge. So yes, to answer your question there is definitely a difference, But even running my Sr 125's through a DAC and Headphone amplifier I still cannot hear the difference between Lossless and 256 bit rate Mp3. And for the record I am a musician with a very refined ear.
stimpy77
(7:25 PM on Sat Mar 7, 2009)
I hate it when people splurge on too-expensive audio hardware and brag about it as if it qualified them to be named "audiophiles".
A true audiophile will notice discrepancies between audio file formats *regardless* of the audio hardware. That said, while I agree that the earbuds sound absolutely horrible, you don't need to spend much more than $75 to get a very good set of headphones whereby the difference between audio formats matters significantly.
Brian (6:32 AM on Tue Mar 10, 2009)
Are you kidding me? How could a "True" audiophile hear a difference in formats on hardware not PHYSICALLY CAPABLE of reproducing an actual difference. I suppose you are a "true audiophile" you can come over to my house anytime and try to distinguish between lossless and 128mp3 on my cellphone.
stimpy77
(2:17 AM on Wed Mar 11, 2009)
Well if you were a true audiophile then you'd know ;) :) :D that indeed a $75 pair of headphones with a frequency response range of at most 100hz on the low end to at least 15kHz on the high end and a fairly flat profile, first of all will work fine for casual listening to most music, but depending on the quality will also sufficiently reveal artifacts and the imbalance of certain frequency thresholds. Even in my cheap car speakers that cost me maybe $30 I have found myself angry with myself for compling a music CD consisting of 128 kb/s MP3s rather than 192 kb/s WMAs because the dynamic ranges just don't come through and some frequencies clearly sound distorted and littered with artifacts. In fact, this is a case in point where sometimes cheaper speakers/headphones can bring about the deficiencies of lower-quality encodings of audio files than higher-end speakers, because I didn't the problem until I got out to my car.
The fact is, lower-quality encodings of files has to do wih compression, not frequencies. If you take a JPEG image and compress it heavily, you will end up with an image that looks blurry and littered with artifacts. The same is true of compressed audio; when you heavily compress an audio file in MP3 or other format, you end up with audio where the detail is all mushed together and strange distortions and unwanted noises begin to show up in the music. Typically the mid-level price range of headphones of speakers ($75 headphones, et al) will *function* in reproducing audio that the human ear can comprehend and that conforms to the signal source moderately well. The only real advantage you get with the higher quality phones is a flatter EQ response. You don't need to spend a lot of money to actually hear these artifacts or droppages in detail and quality in compressed files.
You do, however, need good, trained ears and an attention span.
Jon
stimpy77
(2:44 AM on Wed Mar 11, 2009)
BTW a cell phone is not a $75 pair of headphones. Don't waste our time with rhetoric.
Brian (3:25 PM on Thu Mar 12, 2009)
"A true audiophile will notice discrepancies between audio file formats *regardless* of the audio hardware"
That is what you said, "Regardless" of hardware, that's total crap, hardware plays an important role in sound reproduction since it actually reproduces the sound. I never said that a 75 dollar pair of headphones wasn't sufficient to detect the differences between formats/bitrates. I just disagreed with the the statement that a "True audiophile" should be able to detect these differences on ANY hardware, because Clearly that statement is invalid, since any hardware includes 10 dollar jvc earbuds, Coby brand Wal-Mart stereo equipment, talking children's toys, and yes, even my cell phone. I stand by my previous statement that if hardware cannot replicate a level of detail sufficient to produce a difference in sound quality between two Mp3 encodings of different bitrates, than you will not be able to tell the difference, regardless of your high opinion of your own ear.
Albee (11:33 PM on Mon Jun 8, 2009)
Look, I love good quality music and headsets. I have used several different types that were very expensive and I could here some differnece in some brands. Bose ear buds were the best at about $100. I chose the $29 JVC becuase they sounded great and if I lost them oh well. True Audiophiles would not use any of this crap and expect true sound. He would be at home with his record player and some giant studio headphones all alone with the lights out.
Vinas (9:26 AM on Mon Mar 9, 2009)
128kbps was good in the 90's but I can (sometimes easily) tell the difference between that and 192kbps or higher. I agree though about the equipment. Don't brag about ALAC or FLAC until you upgrade your equipment to actually hear the difference. Up until recently my minimum standard for mp3 is 192kbps which is still pretty good. I think it's probably time to get more into higher bitrates upwards of 192kbps though. My 80GB of mp3s are starting to show their age, mostly because I've recorded the bulk of them at 128kbps. The last twenty or so CDs I've recorded are @ 192kbps but I'm considering moving up to 320kbps instead of a lossless or VBR mp3. Lossless just doesn't appeal to me all that much. I think because of the storage considerations and compatibility issues. Plus, I can't be bothered with DRM so I guess I just hit on the reasons people still use MP3. It works and it's not broken! =)
Me (9:19 AM on Mon Mar 9, 2009)
128kbps was good in the 90's but I can (sometimes easily) tell the difference between that and 192kbps. I agree though about the equipment. Don't brag about ALAC or FLAC until you upgrade your equipment to actually hear the difference. Up until recently my minimum standard for mp3 is 192kbps which is still pretty good. I think it's probably time to get more into FLAC to be honest. My 80GB of mp3s are starting to show their age, mostly because I've recorded them at 128kbps. That is about 15,000 songs folks. =)
Dave
(3:25 PM on Fri Nov 7, 2008)
On a recent trip I was chatting with Elliot Shiner and guys from Panasonic they said there is absolutely no discernible difference in audio quality from a 320 kbps MP3 from a CD. Encoders have just gotten a lot better these days and 320 is almost as big as FLAC. Plus compatible with everything unlike FLAC.
Eli Gundry
(12:03 PM on Sat Mar 7, 2009)
As someone who rips in both MP3 and FLAC, I can tell you the file size will differ greatly between those two format. I rip MP3 at VBR 0 (takes up less space with highest possible quality) and the size is about 6-10 mb. FLAC, on the other hand, is about 20-40 mbs a song. That is a pretty big difference.
Anonymous (2:06 PM on Wed Nov 19, 2008)
Dave,
it's not the size of the file that makes it closer to the original... mp3 is lossy, even at 320, so you cannot remaster a CD from your 320 mp3s, and re-rip it to 320 mp3s and expect to get the same files and quality. Full stop. And FLAC _is_ definitely going to be supported every day a bit more. mp3 was the first and therefore more popular, but with nowadays large media, file size isn't an issue anymore.
Just my 2c
Al
AndrewS (6:28 PM on Fri Mar 6, 2009)
File size *is* an issue for me, since I like to have as much of my music stored on my laptop as possible, which has a mere 120GB HDD. There still aren't many laptops that exceed 250GB storage, and I don't really want an external HDD hanging out of a USB port every time I want to listen to my lossless formats.
I'm as big a fan of FLAC as anyone, but I don't have the space for 300+MB per album.
I'd rather sacrifice a little quality (it's really not discernible at all with 224kbps MP3s and greater, and even difficult to see in a waveform graph) and get more of my music library on my laptop or iAudio rather than feel all smug and superior (as Mat Bitner says) with far fewer FLAC encoded albums.
I don't agree with 128kbps MP3s (or OGGs) sounding the same unless you have $300+ buds. I find 128kbps lossy formats intolerable on my Sennheiser PX100s, basic iAudio buds and even my laptop's Altec Lansing speakers. I find 160kbps is the bare minimum I can stand.
Paul
(10:06 PM on Thu Mar 5, 2009)
FLAC and other lossless formats are nice, but most of the time the differences aren't noticeable. Most people can't really tell the difference from 192kbs and up for MP3s. For bitrates beyond that, good headphones/stereo equipment are definitely going to make the largest difference.
Even though filesize isn't as much of an issue, it's still not negligible. 6,000 songs at decent MP3 bitrates can easily fill up about 50 gigs. When combined with other media and applications, that's not negligible unless you have multiple hard drives.
Anonymous (6:06 PM on Sat Mar 7, 2009)
AAC as a successor to MP3? Are you KIDDING me? Proprietary Apple-only DRM-laden format that is ONLY used for iPods? What the hell are you smoking?
And where the bleep is Ogg in that list? It's actually an open standard! The only problem is Windows users getting screwed over a virtual lack of Ogg players, but I've noticed there's been a lot of Ogg-capable hardware players out there. Linux users would be happy, though.
And don't bring up ANY Microsoft formats, they're worse than AAC. Imagine all the disadvantages of AAC, except now it's as bloated as everything else Microsoft makes, and only Windows Media-enabled players (Both software and hardware.) can play it!
Randall Bennett
(7:17 PM on Sat Mar 7, 2009)
It's not AAC's fault. It's the MPEG4 variant of MP3 (which is MPEG1). Ogg isn't in the list because... it's not a format that needs explaining. :) People who know what ogg is don't need it explained.
stimpy77
(7:19 PM on Sat Mar 7, 2009)
OGG was listed. Its quality, however, was not described. OGG sounds very good, comparable to AAC.
Anonymous (5:27 AM on Sun Mar 8, 2009)
the most lossy audio format is WMA .
Anonymous (6:07 PM on Sat Mar 7, 2009)
AAC as a successor to MP3? Are you KIDDING me? Proprietary Apple-only DRM-laden format that is ONLY used for iPods? What the hell are you smoking?
And where the bleep is Ogg in that list? It's actually an open standard! The only problem is Windows users getting screwed over a virtual lack of Ogg players, but I've noticed there's been a lot of Ogg-capable hardware players out there. Linux users would be happy, though.
And don't bring up ANY Microsoft formats, they're worse than AAC. Imagine all the disadvantages of AAC, except now it's as bloated as everything else Microsoft makes, and only Windows Media-enabled players (Both software and hardware.) can play it!
shoaib2k2
(5:08 PM on Sat Mar 7, 2009)
Informative sutff but one does not take note to these things while listening to music i mean one does look for the best quality available but for me indulging in this geeky stuff is not worth the time
Anonymous (12:25 PM on Sat Mar 7, 2009)
What about OGG?
Anonymous (7:52 PM on Fri Mar 6, 2009)
Dave: Encoders have just gotten a lot better these days and 320 is almost as big as FLAC.
lol @ you, 320 will always be 320kbps
dave c
(2:23 AM on Mon Mar 9, 2009)
Excellent list! I've often wondered about the differences between all the different formats. Thanks for taking the time to gather them and then explain them! As for the post by Mat Bitner, what a joke! Anyone, I mean anyone (except for the totally deaf), can tell the difference between poorly ripped and excellent copies of a song. It doesn't matter what speaker system you have. If the copy is copied poorly, it's going to sound bad no matter what. Do you understand now? child?
Vinas (9:35 AM on Mon Mar 9, 2009)
I think I should point out that for playback I believe MP3 will remain king. If you need to do remastering then make sure you use lossless or better yet 1 to 1 wave (hope you have a couple TB disks). Yeah, I think the point is that MP3 will remain king for the foreseeable future.
reldoc (9:33 AM on Tue Mar 10, 2009)
Music good, noise bad. More music in small space-good. It's still music, even with cheaper headphones. At home I have a nice room good speakers and nice equipment. No headphones.Everyone in the room can enjoy the music....kinda like in real life. I enjoy music even from my cellphone. Sheesh, get a life. BTW, Vinas is right, MP3 owns the marketplace.
donut (6:51 PM on Wed Mar 11, 2009)
This list might be a bit outdated, i don't know. Anyway OGG is widely used in commercial business, most notably in the spotify project. Spotify's public beta started november 2008 and has already a million subscribers. It's expected to grow exponentially to at least five million users this year.
Oh, and you can use spotify for free if you want.
ilkay (3:41 AM on Fri Mar 13, 2009)
I' like to add Trekstor Vibes to the list of players that support FLAC. This is the main reason I bought it. Sound quality is good, menus are a bit weird, but overall I am still impressed by it.
Anonymous (10:13 AM on Fri Mar 13, 2009)
Try this test guys. http://mp3ornot.com/ I could hear the difference on my relatively cheap 5.1 sound in my study($700 Au). Format isn't quite as important as bitrate really, but try listening to a nice acoustic guitar ie john butler in 128 vs 256 or 320 mp3. Even on crap headphones you should be able to hear the difference. The worst problem with apple/itunes/ipod is that default settings in itunes are aac in low quality, 128. This is still lower than 192 in mp3. Nearly everyone who uses itunes doesn't change the defaults and end up with substandard cd rips. People don't understand formats and bitrate so I commend this site for information. My best mate installs car audio at a large australian retailer and laments the fact that people spend thousands of dollars on car audio and connects their ipod to play 128k files. Its a tragedy of not getting the frequencies they are paying for. A good car audio system with tweeters, splits, and sub should really show up what you dont get. Mp3 rules, DRM sucks ***, pity most popular alternative formats are tied up with corporations who have their dollar at stake rather than our listening pleasure. My 2 cents worth..................J
Anonymous (2:08 PM on Fri Mar 13, 2009)
Talking about which digital format sounds best , is like talking about who has the nicest smelling farts.
Neno (11:41 PM on Wed Mar 18, 2009)
Buy **********audioengine a5********* for your music collection and you will hear big difference in sound quality. My mp3 archive sucks even in 320kbps !!!!!!
Chris S (9:27 PM on Sun Mar 22, 2009)
You might want to add Monkey's Audio (extension .APE), a lossless audio format. (http://www.monkeysaudio.com/index.html)
Also, popular for legally traded digital concert records is the Shorten (extension .SHN) format. It's a lossless format available on most platforms. (http://wiki.etree.org/index.php?page=SoftwareYouNeed)
ntec
(10:27 PM on Thu Mar 26, 2009)
It boils down to personal preference more than anything else. Most of the current portable players based on flash memory are still limited in capacity & compatibility. My take is certainly 192kbps MP3 for the best ratio in terms of file size, audio quality, & compatibility with players.
And I'm certainly no audiophile.
Lucas
Noble.SG
Anonymous (12:30 AM on Sun Apr 12, 2009)
Was hoping to find some really useful info on this thread, but alas, yet again, too many one-eyed MAC loving kiddies sprouting forth about AAC.
What I'd like to know: I, like many others have a rather large collection of aging MP3s, WMA, AAC all at differing bit rates. I'm looking for a format and bitrate which will give me a degree of longevity i.e. great sound (a no brainer), will be compatible now, and in the future with, car audio systems, new home audio systems, cell phones players etc.
Any unbiased (i.e. not secretly in love with Steve Jobs) advice would be welcomed.
Edward B (6:23 AM on Thu Apr 16, 2009)
I have all my cd's collection in mp3 files but I wanted to improve the sound quality, one choice is recording again in wav format, but itunes allows me to convert the mp3 files to wav format, can I get the same sound quality in this way?Will be exactly the same as if I record originally in wav format?
Randall Bennett
(9:49 AM on Thu Apr 16, 2009)
No, it won't. You need to rip the original CDs to Wav (though I'd recommend ALAC or FLAC.) You can't magically get more quality out of a compressed file, it has to come from the original.
Edward B (1:34 PM on Thu Apr 16, 2009)
Thanks, your comment has been very useful
Chris Doney (4:24 AM on Wed May 6, 2009)
Hi Guys,, Stumbled Upon this site..
Very interesting stuff
I have an ipod so mp3 still wins for me.. i have my full library in mp3 format (most ripped at 320kbs) so i can use with itunes then i also have a flac library of my fav albums that i can play on the computer.. if i'm burning a cd for use in stereo i will always burn from flac as its a igher quality source.
I feel flac sounds much better than mp3 but its hard to tell when using average speakers.
Just my views
catmonkey (8:04 PM on Tue Aug 25, 2009)
MP3 320 v WAV 1411 for music download? Informative page and wow!! some heated debate. But I wanna know which choice to make when I buy from say Beatport, inorder to burn to disc and play through a cdj on a 6k soundsystem. Thats my question boys and girls. Plus as a result of some of the above comments does burning the track from my i tunes library effect the quality and if so why?