A couple of years back MP3 was the most supported format for portable devices. Then Apple came along and wiped the floor of all the portable devices with the iPod as well as the iPhone. They clearly favour M4A (AAC).

When to choose, right now, the 'best' audio codec to encode music to, which would you choose to achieve maximal independence of portable device vendors: MP3 or M4A?

(I am well aware of Ogg (Vorbis): no market (maybe this changes with HTML5 and more WebKit on portable devices), I am also aware of FLAC: I don't want to discuss long term storage.)

  • 1
    Almost all Android devices can play Ogg Vorbis, FWIW.
    – staticsan
    Aug 20, 2012 at 7:14
  • 1
    Apple did not wipe the floor. Maybe their own floor but 90% of smartphones in the world are Android (yeah, its true. even if I don't like Android, its the truth). Every PC/Mac/Tablet supports mp3 and will continue to do so for generations to come. So yeah, mp3 is not going away just because Apple came up with something of their own. m4a is a good choice if you're using ALAC codec (lossless). Otherwise, mp3 and m4a are same for > 128Kbps. I doubt you care for anything lower than 128k.
    – Mrchief
    Aug 25, 2017 at 2:03
  • 1
    I'm voting to close this question as off-topic because which audio format is the “best” is seeking a highly subjective answer.
    – Ramhound
    Mar 5, 2019 at 21:14

6 Answers 6


If you plan to use your audio files on more than one portable player, especially if you want to use them on future players that you haven't bought yet (so you don't know what formats they will support), MP3 is more or less your only option. Even for players with support for other formats, that support is often incomplete and buggy.

Unless you make sure to only buy Rockbox-compatible players. Then you can use pretty much any format you like.

Of course, the only truly future-proof solution is keeping lossless copies of everything and transcoding to lossy formats for mobile players.

  • 2
    yah, sadly the last paragraph seems to be the only option in the long term.
    – akira
    Oct 9, 2009 at 6:56
  • 2
    +1 for mentioning roxkbox. I have never bought a portable audio player because of limited format support. I will have a look at it.
    – ufotds
    Jan 4, 2011 at 15:11

AAC is in very widespread use today. For example, Internet video streams are usually encoded in H.264, and usually uses AAC for its audio. Almost any modern portable media player is able to play back both MP3 and AAC.

However, there are two things to take into account:

  1. AAC is the more efficient codec, meaning that it takes less storage space (=bitrate) for the same audio quality (or the same bitrate for better audio quality). So, from a purely quality-oriented point of view, AAC is plain better and support is widespread enough to give it a go.
  2. AAC is slightly more complex than MP3, which may lead to a slightly higher computational load and hence, slightly decreased battery life especially on older devices. However, higher bitrates generally decrease battery life, too, so this is only a valid argument for MP3 files and AAC files of similar bitrates.

Overall, I would use AAC without hesitation.

(If you want to know more, I posted something about audio quality of MP3s and AAC files a while ago.)

  • 14
    MP4 is not an audio format - it is a media wrapper format that can contain video and audio streams or a variety of different types. When they questioner mentions mp4(aac) that is referring to an mp4 container with a single AAC encoded audio stream - you could equally store an MP3 stream in an MP4 file or many other audio encodings such as AC3. The confusion (people thinking MP4 is a distinct audio format) is due to the way some manufacturers market "mp4" capable devices. They are even calling some MP5 players now, which means nothing more than "it goes up to 11!". Oct 8, 2009 at 9:06
  • True. I was speaking about mp4audio, or *.m4a. Could you name it that way?
    – bastibe
    Oct 8, 2009 at 13:51

MP4/M4A (both are AAC based files) render much better at lower compressions. A 128kB range AAC file stomps mp3 in the dirt in sound quality. Above 220, a little less so, but still way better. If you are trying to cram thousands of songs into a limited storage space, AAC will put a smile on your face. If you have a huge mp3 collection and most of it is above 260kB, don't waste your time converting them; just go with what you already have for now. If you are starting from scratch or are working on a new database (taste in music changed over the years) go AAC. More devices will support them in the future. Several major music hardware manufacturers already include AAC decoding on their devices. AAC -IS- a better compression engine than mp3. There were lots of cassette tapes around at one time; where are they now? In museums. Bye bye mp3.


MP4 is the new MP3 (although as said by other posters, its just the container for AAC audio)

In addition MP4 supports many extra types of streams, including pictures, video and other rich content. True that MP3 supports lyrics and photos via the ID3-Tag, but now its built into the container specs, which means portable players can access the various types of rich content.

Vendor-independent wise I'd say its highly subjective, depending on the player you get, and what content you want to store. Only music? I say MP3 is a safer option... until they stop supporting MP3 on portable devices in 2 decades or so.

  • content: "audio codec"
    – akira
    Oct 8, 2009 at 10:53

The independence you're talking about is not restricted by a format but by the device you may (or rather may not) buy. The choice is entirely yours!

And FLAC (or Monkey's Audio) is not about 'long term storage' but all about quality and decent "portable devices" that do support these formats are plenty.

(I certainly do not care much for this 'floor wiping' corporation you felt inclined to mention. :)

  • the point of the question was to find out the greatest common denominator, codec wise, so one can go and buy almost any device and it 'will just work'. flac: the amount of items you can store with flac compared with the amount of items you can store with the lossy codecs is rather small. if storage size is not relevant for you, the 'right' answer to my question would be 'wav' because 'lossless' (analog->digital loss aside) and bigger support on a number of devices.
    – akira
    Oct 9, 2009 at 6:50
  • and that is exactly why you should make such a question CW, it's about personal preferences, and as for the future support of any format, may i refer you to my crystal ball? :)
    – Molly7244
    Oct 9, 2009 at 9:28
  • oooo, you have a crystal ball? can i borrow? Nov 2, 2009 at 5:27

Strictly speaking of music, mp4 sounds better than mp3 at the same bit rate (commonly 256 Kbps). Why? because the slices of the mp4 file are spaced more closely together. This results in more slices over the length of the audio file. The result is cleaner high frequencies, cleaner mid frequencies, and cleaner low frequencies.

An mp4 file is larger in size for a 3 minute recording than an mp3 for the same recording. The result is higher fidelity.

Consider this: More sampling per second gets you better fidelity. Because the sampling occurs more frequently, more bits for any one second results in cleaner sound. For a 3 minute song, the file size will grown about 10-15%. That difference makes for smoother transistions and less loss. THerefore, the sound quality improves.

However, built in to mp4 is the ability to sample both audio and video. A video in mp4 vs the same video with AAC video and mp3 sound, is somewhat smaller (not much), but the mp4 video contains both the video and the audio and you still get noticibly better sound (but not as much for an audio only file). Stil, the quality fo the audio can be heard, but not as much as you'd get for an audio only file.

So, the bottom line: For the best audio only sound, use mp4. For a little bit better audio in a video, use mp4 again. The trade off is the file size, but with today's Terrabyte sized solid state drives, there is more than enough room for the extra size in the mp4 file. WHAT REALLY MATTERS is the sound that reaches your ear. File size means nothing. Sound quality is everything.

If you compare the same Mp4 file against a recompile at mp3 at the same bit rate, you WILL hear a difference. Though it is barely noticable, it is noticable.

To get the best, get mp4 files. To get the very best, get AAC files (uncompressed) or Wav files (uncompressed). But you'll find that there is barely noticable difference between the uncompressed and the mp4 compression. But if you compare the uncompressed to and MP3 (highest bit rate possible is 256 KBps), you will hear a noticable difference.

Bottom line: MP4, because it takes more samples than an mp3 in any given time period, produces the better audio. The other choices that are uncompresssed result in the best sound quality (depending on type of sampling [SAAC is preffered]), you'll have file sizes that are considerably larger with no hardly any discernable difference in sound quality over the 256 kbps mp4, but a huge difference compared to a 256 kbps mp3 file.

So, when in doubt, always choose the mp4 file. You can save extra space by converting to mp3, but if you start with the mp3 and convert it to mp4, you'll gain nothing because the mp3 is already degraded.

Your best source for mp4 is iTunes. Amazon sells variable bit rate (ugh) mp3 files in their digital downloads, and these sound terrible! I know. I've been there, done that.

Re: Older songs and albums at iTunes. Don't. Just plain don't. It is my experience that these files are mp3s that have been converted to mp4. If you can find a remaster, then the tapes used to make the album have been cleaned, and the new file starts with mp4 format. Get these. Avoild older music that does not say 'remastered', or your audio will suffer and you'll soon be watching for the remaster.

A personal experience: I was strapped for money, but wanted to replace my 128kBps Sgt Peppers album, so I bought the album from Amazon which uses variable bit rate. Two songs had the vocal buried. These were "I Get By With a Little Help From My Friends" and "When I'm sixty four". So I fired up my audio converting software and it told me that both of these tracks downgraded the sampling to 64 kbps! That is unacceptable. Would amazon replace thes tracks? No. They could not. So I hopped over to iTunes and got these two at fixed bit rate 256 kbps mp4. This solved the problem. Still, the rest of the album suffered because variable bit rate mp3 was used. I eventually replaced the whole album (spending nearly twice as much) by buying it from iTunes which always uses mp4. The result, in comparison by track to track, was incredibly superior.

So always look for fixed bit rate mp4 files. This is itunes' standard, albeit some of the older music has not been cleaned on the tape, and these suffer because that tape has not been cleaned (of noise and hiss and pops). But if this is your only option, get the album, then wait for a remaster from tape. You'll have the album and can upgrade it soon enough.

Mp4 wrocks over mp3. There is no question about it. Why? More samples per second (video sampling slices are used along with the audio sampling), and the audio improves considerably.

Not the answer you're looking for? Browse other questions tagged or ask your own question.