First look: Digital Media Core, Audio Format: MP3

I wanted to throw this by readers before posting a final version to the SuperSite.It's an early version of what will likely be the first article in the "Digital Media Core" series, which will eventually cover various digital music, photo, and video topics, as well as backup and media sharing. I've got an outline of sorts that I can post if you think that's valuable, but the intention is to keep the articles in this series up to date over time so that they make sense and are relevant no matter when they're read (unlike, say, a review, which is by nature a slice of time). Anyway. Not everyone will agree with all of the advice here. And there's some additional material I'm trying to figure out how to incorporate (mostly tips) that aren't here yet. Any links within the article aren't "there" yet either. Anyway, let me know what you think. 

Digital Media Core
Audio Format: MP3

Background
Back around 2002 or so, I was convinced that Windows Media Audio (WMA) was the future of digital audio: It offered better compression, better fidelity, and smaller file sizes than the industry standard but ancient MP3 (MPEG-1 Audio Layer 3) audio format and Microsoft was pushing it hard with increasingly impressive releases of Windows Media Player, Media Center, and what seemed like a rich partner ecosystem for devices and services.

But then Apple happened. The company released its first iPod in 2001 and followed that up a year later with a Windows compatible version and then. Then, about a year after that, Apple released the first Windows version of iTunes, its iPod and digital music management system and, of course, front-end to the iTunes Store. Apple wanted nothing to do with WMA, for what I assume are obvious reasons, and was instead foisting yet another audio format on consumers. This format, AAC (Advanced Audio Coding), is the successor to MP3 from a marketing perspective but is, like WMA, really completely different technology.

The success of Apple’s iTunes Store--which, until recently, sold songs only in a proprietary version of AAC called Protected AAC--suggested that maybe Apple, and not Microsoft, would define the next generation of digital audio formats. And its iTunes software, not coincidentally defaulted to plain vanilla AAC for CD ripping whereas Windows Media Player defaulted to WMA.

Technologically, AAC and WMA are very similar. They use completely different lossy compression schemes but achieve very similar quality and file sizes at identical bit rates. WMA has the edge in compatibility when it comes to the variety of devices and software that work with either format. AAC, however, has the edge in sheer numbers, but only because the AAC-compatible iPod has sold so fantastically well.

The problem for Windows users--i.e. "the world"--is that AAC doesn't play nice with products made by Microsoft and its partners. AAC isn't compatible with Windows Media Player or Media Center, though you're welcome to buy expensive and balky third party codec packages if you really want that functionality. But even if you do that, you won't be able to access AAC content via a Media Center Extender. (Curiously, AAC is compatible with two recent Microsoft products, the Zune product line and the Xbox 360, but on the latter only through the comparatively primitive blade user interface.) AAC doesn't work with most third party media players, set-top boxes, or portable audio devices either.

WMA actually met these requirements before the iPod rocketed to success. And that's where today's technological stalemate begins. Both AAC and WMA are excellent. But neither is fully compatible across all the products you're going to want to use now or in the future. They're both non-starters. In my opinion, you, as a Windows usres, would crazy to back either format at this point.

Enter MP3
Fortunately, we have that age-old standby, MP3, waiting in the wings. MP3 is everything that AAC and WMA are not: It's compatible with every single software product, service, set-top box, portable media player, or other device you'd care to use. It is PC and Mac agnostic, works equally well in iTunes or Windows Media Player, and can even be configured as the default CD ripping option in both products. Heck, it works great with Linux too, if you should ever move in that direction, you rebel.

MP3 isn't perfect, but its biggest problems are very much offset by some recent developments. For example, MP3 doesn't offer the same sophisticated compression schemes found in AAC or WMA, so you'll need to rip songs in a higher bit-rate with MP3 than you would with either of the other formats in order to achieve the same quality. This results in bigger files, naturally, but thanks to the ever-expanding size of today's hard drives, the file size of individual songs is rarely an issue. Only the most Scrooge-like user would complain about the difference between a 3 MB and 4 MB song file.

Another surprising development has conspired to make both AAC and WMA passé. Now that the recording industry is finally beginning to begrudgingly embrace the sale of unprotected song files (that is, music files that are not protected by Digital Rights Management, or DRM, technology), online music services are dropping the proprietary formats of the past for pure, simple, and compatible MP3. (Well, everyone but Apple: For some reason, the iTunes maker has decided that its non-DRM tracks should cost more than the protected versions and should be encoded in Windows-unfriendly AAC.) As of this writing, Wal-Mart and Amazon.com are both offering millions of DRM-free MP3 audio tracks for sale online. Even Microsoft has gotten into the game: In November, it will relaunch the Zune Marketplace with over 1 million "pure" MP3 tracks (rather than pursue some lame non-DRM version of WMA). Other companies will no doubt offer MP3 options soon as well.

The game's over, folks. MP3 won.

MP3 in the real world
I use MP3 exclusively for any audio tracks I create myself, typically by ripping audio CDs to disk, and I recommend that you do so as well.

That said, there are audiophiles and technology trolls out there who might recommend other courses of action, such as using lossless WMA or AAC formats, which take up dramatically more disk space than MP3 files, but don't lose any audio fidelity when compared to the original source. (Don't be confused by the term "lossless," however: These formats are still compressed as, incidentally, are the CDs from which most digital audio files are ripped.) This is a foolhardy idea, unless you will never use a portable media device or enjoy the thought of storing and managing two copies of your music collection, one in lossless and one in another format that's been transcoded from the lossless masters. I'm not sure about you, but in my opinion life is just too short to bother with that kind of silliness.

Others may recommend bizarre and unpopular formats like FLAC or OGG. These people are also misguided: While these formats may offer some vague technical advantages over other audio formats, they are even less compatible than AAC or WMA. The people who do use (and advocate) these formats are generally more concerned with religious issues surrounding their disliking of proprietary technologies or products made by companies like Apple and Microsoft. My advice here is simple: Avoid these formats.

Media management
As Windows users, your choices for managing MP3 and other audio files are nearly limitless. Honestly, many of these applications are at least good or excellent, so which one(s) you choose should be based on other considerations. For example, if you're going to access your media collection from a Media Center PC or Extender in the den, you should organize your content with Windows Media Player, since those products derive all of their song meta-data from that application. Zune guys, obviously, should use the Zune software. Those with iPods, iPhones, or even Apple TVs (all 6 of you--relax, I'm one too) will want to use iTunes. If your primary access point for music is another type of portable player, you'll want to use whatever software works with the device; typically, that's Windows Media Player, but it could be Real Player too. Either will work fine.

While there are some conceptual differences between these products--I use iTunes and Windows Media Player primarily at the moment, but plan to use the new Zune 2.0 software extensively when it ships next month--I don't believe many people will have issues moving back and forth.

Personally, I use iTunes to manage the "master" copy of my music collection. That is, I allow iTunes to organize my music collection into whatever folder structure it likes, which makes it easier to backup and copy from system to system. I use iTunes to apply album art to my song files (the automated system Apple has works pretty well but I end up having to manually copy many album art images). I rate songs in iTunes and on various iPods, which is handy (if time-consuming) for creating smart playlists. (For example: A greatest hits CD from a particular band is quite easy to make when you've rated all the songs.) It's great for finding song duplicates. It has pleasing visual styles like Cover Flow mode and has recently turned into a first class video player too. (We'll look at that in a different article.)

iTunes isn't perfect, and certainly there are some advantages to other players. Windows Media Player and the first generation Zune software both feature excellent "stacks" views of artists and genres, which are quite nice. And though you can't play DVD movies with iTunes, DVDs works just fine in Windows Media Player.

Frankly, there's no reason you can't use all three. Zune quite nicely copies over the meta data you've already configured in iTunes and Windows Media Player and is thus the friendliest of the three in that regard. (It even picks up iTunes ratings, which is key.) Otherwise, you should look into MusicBridge, which was my software pick of the week in Episode 35 of the Windows Weekly podcast. This wonderful and free utility lets you manage your music collection in either iTunes or Windows Media Player and then manually (but very quickly) apply meta-data like album art and even ratings to the song library in the other app. This is genius and it really solves some of the real world issues that arise when moving between these applications.

Ripping CDs in MP3
This is another area that's sure to cause some bickering from the audiophile crowd, even from those that agree that MP3 is the way to go. That's because many people actually have very strong opinions about which applications you should use to rip audio CDs to your hard drive. I have to be honest here: I really couldn't care less. I happen to use iTunes or Windows Media Player, in general, and have never really noticed a difference.

I do have some advice about the bit rate you should use when ripping audio to MP3 format, however. With the understanding that this is forward looking, I don't think it makes sense to rip songs in anything lower than 256 Kbps. Over the years, I've adjusted my thinking on this: Originally, it was 160 Kbps, and then I moved to 192 Kbps because it happens to be a preset in iTunes. And while I can't say I've ever done a serious "taste-test"-style listening comparisons, my argument about hard drive capacities (both on PCs and portable devices) above renders any concerns about file sizes moot. If there is a happy middle ground between supposedly "CD quality" 128 Kbps MP3 files and lossless WMA/AAC tracks, and I believe there is, it's 256 Kbps. Anyway, that's what I do.

The other debate you'll see around MP3 and other audio formats is whether to use Constant Bit Rate (CBR) or Variable Bit Rate (VBR) encoding. CBR files are generally larger in size because VBR files literally use fewer bits to encode less complex passages in songs. So whereas a 256 Kbps CBR MP3 file utilizes a constant 256 Kbps encoding rate, a VBR version of the same file will use a variable bit rate that can reach as high as, but not exceed, 256 Kbps. The end result should sound virtually identical to a CBR version of the song, depending on the sophistication of the encoder you're using, so the primary advantage of VBR files is the disk space savings.

My take on the VBR/CBR debate is one of absolute indifference. As noted previously, the disk space issue doesn't seem like an issue to me unless we're discussing lossless files. So I do use CBR, which is typically the default setting in most media player applications. You may want to experiment with VBR, however, and calculate how much space you can save over the course of ripping your CD collection to the PC.

Converting files from another format
So let's say you've foolishly squandered a lot of time and energy ripping songs to your hard drive in AAC or WMA format. (If I had a dollar for every person whose written me because they accepted the AAC defaults in iTunes by mistake and then were later surprised those songs didn't work anywhere else, I'd be a rich man.) You may be tempted to try and convert, or transcode, those songs from AAC or WMA format to MP3. In general, my advice is to avoid doing so unless the original tracks were encoded at 160 Kbps or higher. The problem is that all three of these formats use completely different compression schemes. And when you transcode a file--or recompress a compressed file, but using a different type of compression--the end result is always substandard. The songs I've transcoded in this fashion are generally tinny sounding and lack depth. They're a mess.

If you absolutely must do this, make sure that your transcoding into a high quality MP3 format: The higher the bitrate, the less information that gets lost in translation. (Likewise, higher quality source songs will result in better transcodes.) The Windows version of iTunes, for example, will transcode imported WMA files into whatever file format you've configured in the application's Importing setting. So choose Custom and shoot for 256 Kbps or above before importing those files.

Another tack to take is to actually create audio CDs of your WMA or AAC songs and then re-rip them back to the hard drive in MP3 format. This admittedly time consuming process will result in the same tininess noted above and is more time consuming. But if you are going to do such a thing, here's one bit of advice: Keep a CD-RW disc handy: You can create an audio disc, re-rip it to the hard drive, and then erase it and start all over again. I keep a single CD-RW around just for this purpose.

Backing up
While I plan to write a separate Digital Media Core article solely about backing up, it bears at least mentioning here: Too often, people don't begin rigorous and regular backups until they suffer a catastrophic hard drive failure and lose something important. With more and more of us storing all kinds of personal and professional data on PCs--years of family photos and home movies, for example--you don't want to be a statistic. Back up early and often.

Windows Vista actually makes this process easier, thanks to a decent backup application, and Windows Home Server is even better. But you don't need the latest and greatest software to perform regular backups. And forget recordable optical disk media: Go with USB, Firewire, or network-attached storage, and make sure you keep a copy offsite in the case of theft or a natural disaster. (My parents happen to live in the same town as I do, so we swap out a 1 TB Firewire drive there every week or so.) Keep multiple copies of data around too; I typically copy my entire photo collection to every PC in the house just in case.

Discuss this Article 8

joemaruschek
on Oct 5, 2007
This little statement made me sign up on your site just so I could ask you about it. What do you mean when you said: "These formats are still compressed as, incidentally, are the CDs from which most digital audio files are ripped?" I was under the impression that audio CDs carry pure 16-bit 44.1kHz stereo digital audio, of course with added error correction codes, sub-codes, etc.
mdsharpe
on Oct 5, 2007
These Pingback comments are really very annoying. Anyway, joemaruschek: the audio stored on CDs is compressed (a lot, typically, these days) in terms of dynamic range, rather than in terms of data compression. I think that is what Paul is referring to. I enjoyed this article. However, I seem to fit into one of your minorities, because I rip all my CDs to Lossless WMA. This works fine for me, because I have the following scenario: - I often listen to music whilst at my PC, and enjoy knowing that the songs I have ripped are the same quality as the original - It streams perfectly well to my Xbox 360, both whilst playing games and when using the Media Centre Extender - When I want to sync some music to my portable music player, I don't mind waiting the extra few minutes whilst Media Player converts it to a lower bitrate
joemaruschek
on Oct 6, 2007
mdsharpe: I guess that's the point I was trying to make: there are two different meanings of "compression" and I think that Paul was getting them confused. You got data compression on one hand (lossy or lossless) and dynamic range compression on the other. They are independent of each other, so Paul should be very clear about which type he means. For example, even though the CD might actually use some dynamic range compression, the data on the CD doesn't use any data compression techniques; it is just PCM audio. And I'm not really sure what the purpose of this article is supposed to be. A tutorial about using digital audio? How Paul stores his digital audio? Best practices?
joe-dokes
on Oct 6, 2007
Paul, Please stop with the FUD. AAC is .mp4 it was created by the same body that created .mp3 The only reason .mp4 or AAC is "windows unfriendly" is because Microsoft refuses to support it. .mp4 is an open codec just like .mp3 microsoft just needs to pony up the cash and pay the fee, which is something they are loath to do. Is it smarter to encode in .mp3 or .mp4 I'm not sure. Since I use iTunes exclusively to manage my music, I encode in .mp4. Am I afraid that someday I will have a portable music device that won't support .mp4 not really. Approximately 90% of all portable music devices now support .mp4 I would argue that it will be 100% by the end of 2008. Regards Joe Dokes PS fix the pingback crap.
peterkirn
on Oct 7, 2007
I'm completely, totally lost. AAC is Windows-unfriendly, except for: Videolan VLC (which is free) iTunes for Windows (which is also free) Winamp (still one of the great media players of all time, free) MediaMonkey (which is cheap) Yahoo's media player (free) Rhapsody (free) Windows Media Player, via free plugins like this: http://www.orban.com/plugin/ Not so much FUD as just plain wrong. Don't get me wrong -- buying MP3 files is convenient, and I think you do run into hardware compatibility problems off Windows. So, you know, if you have AAC-compliant hardware (and there are at least a few Windows-centric portable players that offer either AAC, or OGG, or both), you go with AAC. If not, you go with MP3. But by the count above, you've got a lot more choices as far as media players on Windows than on the Mac. In fact, the only orphaned, useless format I see is generally WMA. MP3 won as the lowest common denominator for download sales, but that doesn't mean anything for PC playback of files you're ripping, or web distribution (look out for which codecs wind up in video players), or anything else. This whole thing seems like a non issue.
SVJDesigns
on Oct 8, 2007
I ran into some of these issues recently when I was looking to reconvert my CDs to a compressed format. Over the years, I've ripped my CDs in a variety of bitrates of MP3, starting with 128kbps (sounded good to me at the time) and finally ending up with 192kbps. As a result, my collection was a mish-mash of lower-quality and higher-quality tracks with variable levels of tagging and artwork. So, then the issue of how not to repeat the mistakes of the past came to the forefront. If I was going to invest the time of re-ripping all those CDs, I wanted to do it as "right" as I could. Further complicating the issue was the fact that I have an m-series Sandisk portable player (no AAC), an iPod (no WMA), and an Audiotron (no AAC, no lossless of any kind). Ideally, going lossless would be the way to go. At home, where I have better equipment, I could enjoy the same quality as the original CDs. (Let's face it, any kind of lossy compression is a compromise between size and quality, and if you don't need to compromise quality in certain situations, you shouldn't) What I wanted was a way to rip the CDs easily into a format that can store the audio in a lossless format that could be easily converted into whatever format I needed right now, plus any format that I might need in the future. Converting from a hard drive is a lot quicker than re-ripping all those CDs. What I found after doing some research was dBpoweramp: http://www.dbpoweramp.com/ It handles the ripping to WMA Lossless with good tagging abilities, including artwork, and does secure ripping for judging the integrity of the rip (scratches, etc.). For those with multi-core or hyperthreaded CPU's, the registered version of the software goes to town, using the multiple CPU's to speed the encoding process. I then manage the lossless tracks with Windows Media Player, just in case I need to tweak some tags, import new artwork, etc. To provide something that my portables and my Audiotron can play, I then use the dBpoweramp converter to convert the lossless files into 192kbps VBR MP3's. The converter can also take advantage of multiple CPU's to speed things along, and I just let it run overnight to convert the entire lossless collection into a lossy collection on another part of the hard drive. Everything that I have now is able to play my music collection, and I'm prepared for the future for when the market changes and my players have different capabilities. When I replace the Audiotron with something like the Squeezebox that can play lossless files, I've got a great collection of my music in the highest quality format possible. The time invested is not much more than it would have been if I just used iTunes or Windows Media Player to do the ripping. The biggest issue that this setup has is that the ratings assigned to tracks in Windows Media Player are not saved in the lossless file. It doesn't appear that iTunes stores its ratings in the file either, so ripping to Apple Lossless and managing the library through iTunes would help with that situation. Since neither player is able to manage different libraries, I am forced to manage the lossless and lossy libraries with separate programs. Aside from this small glitch, I feel like I have a very workable system, and I recommend it to anyone looking to have the most flexible music library capable of the highest quality possible for the given scenario. Without a program like dBpoweramp, however, it wouldn't be worth the hassle and you would just have to use some program and hope for the best, with the knowledge you'll probably have to redo your work at some point down the road.
Amp300
on Oct 8, 2007
I'm not sure I completely agree with your recommendations. While I agree that MP3 is the most compatible format, it does have it's share of problems, some of which were fixed in both WMA and AAC. While you stated that you are not inclined to do listening tests to determine the best format and bitrate (and I think this makes you like most normal people) there are those on the Internet (like the quality zealots at http://www.hydrogenaudio.org/) that have done extensive testing. In a double blind test, most people can't hear the difference between 128 VBR MP3 and CD and even people with "golden ears" have trouble once the bitrate is 192 VBR (except for certain problem samples). While HD space is cheap... and I agree with using 256 VBR if you are primarily listening on a HTPC with decent speakers, it doesn't make much sense to use such a high bitrate if you are primarily listening on the go. For those of us that have an iPod Shuffle or similar Cowon or SanDisk 1 GB player, it makes much more sense to rip at 128 VBR. Between the fact that you're using headphones on a portable device and the amount of background noise that exists when you're on the go... you probably won't notice the missing bits... and you'll fit double the music on the player. I'd also like to note that not all MP3 encoders are created equally. Extensive testing has shown that the LAME MP3 codec sound noticeably better than the FhG codecs included in iTunes and WMP. Further, AFAIK, your description of how VBR works is inaccurate (at least for the LAME encoder) as using VBR allows the bitrate to go above or below the setting to achieve a constant quality, i.e. the selected bitrate is not a bitrate cap as you described.
Waethorn
on Oct 8, 2007
"Extensive testing has shown that the LAME MP3 codec sound noticeably better than the FhG codecs included in iTunes and WMP." That's not so with some of the older, slower versions of Fraunhofer's MP3 codec. In the older versions, 112Kbps CBR MP3 was actually considered indecipherable from 128Kbps, and had a full-range response frequency (22Khz). Many new "fast" codecs use a lower response frequency that minimalizes down to 16Khz. The only program of note that actually allows a full response frequency (even including LAME) is MusicMatch Jukebox's MP3 codec at high quality mode. "your description of how VBR works is inaccurate (at least for the LAME encoder) as using VBR allows the bitrate to go above or below the setting to achieve a constant quality" There are different types of VBR. I think Paul was thinking of Peak VBR, not Quality VBR. Most programs use Quality VBR, as they will often ask what percentage of quality you want, and perform only single-pass encoding. The other encoding format is two-pass, and is designed around particular bitrates. With two-pass encoding, you can specify an average bitrate, optionally specifying a minimum and maximum, depending on the capabilities of the codec of course. Each method has it's own pro's and con's. In Windows Media Encoder, I've found that 2-pass CBR gives you higher audio quality at predictable storage sizes than 1-pass, without causing any incompatibilities that VBR can (car WMA players anyone?). Windows Media Audio 10 Professional is also often overlooked, and for devices that are compatible, it will offer even much higher quality than the standard Windows Media Audio 9.2, however, there are limited choices for 2-channel 16-bit audio in WMA 10 Pro VBR format (only 64 and 48kbps unfortunately), which will limit compatibility with devices - you should use CBR in WMA 10 Pro for more options. The differences between 2-pass CBR and 2-pass "Bitrate" (average) VBR in Windows Media Encoder at the same actual bitrate isn't all that much different.

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