Managing Your Digital Media Part 1: Lossy Audio

Every day, digital media spreads from person to person, from computer to computer. Sometimes it's done legally, sometimes it's not. But regardless of how you've amassed your digital audio collection, you need to keep things organized. Part 1 of our "Managing Your Digital Media" segment is all about lossy audio.


The Basics

First, it's a good idea to understand the difference between lossy and lossless audio. Look at the root of the noun: lossy means that some material is lost and lossless means that no data has been lost from the original source material. I'll give you an analogy for a moment.

You've got a bunch of bricks (the data that contains your song). You need to store these bricks somewhere, so you look for a box to put them in (the codec or file format). You can throw all of the bricks in a big box and they'll fit just fine. All the bricks are in there, so this is an example of being lossless. But let's say that the box you put the bricks in takes up too much space in the garage (your hard drive). You know you can probably do without a few of your bricks, so you toss those out and put them in a much smaller box. Now you’re taking up less room in the garage. You’ve had to give up some of your bricks, but you might not even care. This is an example of being lossy.

You can visibly see the difference in the image below.


Of course, there are different ways of storing your information in a lossy format. Almost everyone is familiar with the term "mp3" and it"s one of the most popular codecs out there, but do you know what other options you could use? Perhaps we will compare a few to the MP3.


Alternatives to the MP3 Dinosaur

1. AAC – Advanced Audio Coding. This is the default format for anything and everything Apple, including the iPhone, iPod, and iTunes, but it's supported on pretty much every portable player out there. This format was developed in part by Fraunhoffer IIS, who were the original developers of the MP3 algorithm, and has been touted as the successor to the MP3. It's deviation from MP3 includes:

- Supports 48 channels of audio, whereas MP3 supports 2 channels in MPEG-1 mode and 5.1 channels in MPEG-2 mode.
- Has a wider bandwidth of sample frequencies. Where MP3 can range from 16 kHz to 48 kHz, AAC can range from 8 kHz to 96 kHz. This is very good for getting an accurate digital representation of the original source.
- Higher coding efficiency for both stationary signals and transient signals.
- Handles audio frequencies above 16 kHz significantly better than MP3. - Supports a bit rate between 8 and 529 kbit/s.
- Supports Digital Rights Management.

2. RA – Real Audio. This format was developed by RealNetworks, the makers of Real Media Player, amongst other things. It's most commonly used in streaming media from the internet. Real Audio supports several different codecs of varying sample and bit rates. It hasn't been widely adopted as a method of transferring digital audio outside of the occasional streaming audio website. The likely cause for this is that there aren't many media players that support the format outside of RealNetworks' own player.

3. Ogg – Ogg Vorbis was initially developed as a response to the MP3 when it was announced that there were plans to charge licensing fees for the MP3 audio format. It is an open-source approach, meaning it is completely free and unrestricted by patents.

- Ogg is extremely flexible in the sampling rates it supports, ranging from 1 Hz to 200 kHz.
- Ogg also supports a wide variety of bit rates. If you assume a sampling rate of 44.1 kHz (the standard CD sampling frequency), an Ogg encoder will output a variable bit rate between 45 and 500 kbit/s, depending on the quality setting that is specified.
- Independent listening tests have suggested that at mid to high bitrates Ogg has better quality than MP3 encoded audio.
- Ogg is largely DRM free.

4. WMA – Windows Media Audio is a proprietary format developed by, surprise, Microsoft. There have actually been a few revisions of the original format to create WMA Pro, WMA Lossless, and WMA Voice. This is considered one of the most supported formats, in direct competition with MP3 and AAC.

- WMA Standard supports stereo output (ie. two discrete channels).
- Offers a sample rate of up to 48 kHz.
- At lower bit rates, WMA has been interpreted as better than MP3, although not quite as good as AAC in terms of quality.
- At higher bit rates, the differences become less distinguishable.
- Supports Digital Rights Management.


So you can see the alternatives to the MP3 format are out there. They were all developed as an alternative to MP3 due to perceived disadvantages of the format. But why is MP3 still the most common format?



MP3 – King of the Castle

MPEG-1 Audio Layer 3, which is more commonly known as MP3, is definitely the most popular lossy audio format out there. Development started in 1987, led by members of Fraunhofer IIS in Germany. It quickly became the unacknowledged standard for lossy audio encoding as it provides high compression rates while still retaining relatively respectable quality. The MP3 format applies a series of filters that remove some upper frequency content. This is often acceptable to the human ear as the upper limits of a human's hearing is considered 20 kHz, with a much lower cutoff frequency being fairly standard particularly as we age.

The MP3's biggest advantage is the acceptance it has already achieved. While other formats are trying to gain ground, more audio is being encoded in MP3 format every day. It is widely supported in almost all relevant software and hardware. It also provides fast decoding which is key for efficient playback. Still, it’s performance is a little sub-standard when compared to other more modern formats. It does have a maximum bit rate at which it can rip which may fall below your desire (320 kbit/s) and it’s sampling rate does not lend well to high definition audio (doesn’t support sampling at a rate higher than 48 kHz).



The Future of Lossy Audio

Lossy audio is pretty much standard across the internet. As of late, it has seen some considerable popularity as the bandwidth each user has access to increases, as does the storage space available in both computers and portable devices. The large number of transcoded lossy audio files on the internet is very astounding, especially in mainstream peer-to-peer file transfer programs like Limewire, Kazaa, etc. This has led to a push from legal vendors and illegal file traders alike to seek out lossless audio files.

How is lossless a viable approach? What are the real advantages to lossless audio? Keep an eye out for Part 2 of our Managing Your Digital Media segment. If you have any questions or comments about the more technical side of how each codec functions or just want to show support for your preferred format, be sure to register if you haven’t already and leave us a comment.