Getting to Know Your Audio Files

If you ever wondered what the heck a FLAC or an OGG file is, this guide will tell you everything you need to know, as well as compare and discuss the quality of audio file conversion rates.

This is a guide to all the different types of audio files out there, as well as a look at what variables are involved in making them. From turning audio files into the type of your choosing, to simply making better audio CDs, we’ll cover all the audio basics.

Many times I’m sure you’ve come across a .FLAC or .OGG file and wondered what the heck it is, well wonder no more.

TABLE OF CONTENTS:
AUDIO FILE TYPES
WHAT FORMAT IS BEST?
COMPARING AUDIO CONVERSION BITRATES
CONVERTING AUDIO FILES

To start, we’ll go over the basic audio files one usually encounters when downloading. We’ll cover the variety of types and forms and what they mean in terms of quality, size, and meaning.

wav
WAV (or WAVE), short for WAVE form audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. WAV files store music in exactly the same format as on a CD. They’re the highest quality sound files, but by far the largest in size. To note, Audio CDs do not use WAV as their storage format. WAV is a data file format for computer use only.

.aif/.aiff
Audio Interchange File Format (AIFF) files are the same as WAV files, but are read as such by the Macintosh OSX. Thus, for it’s profile and characteristics please see the WAV description above.

.flac
Free Lossless Audio Codec (FLAC) is similar to MP3, but lossless, meaning that the audio is compressed without any loss in quality. Unlike lossy codecs such as MP3 and AAC, it does not remove any information from the audio stream. Simply put, FLAC files are identical in quality to those of the WAV file format, but are smaller in size from their compression.

.ape
Monkey’s Audio (APE) is a lossless audio compression codec. Unlike lossy formats, such as MP3, Monkey’s Audio does not permanently discard data during compression. A file compressed with Monkey’s Audio sounds the same as the original file, no matter how many times it is uncompressed and reencoded. Monkey’s Audio achieves compression rates of around 40–50% without loss of data. So like FLAC , APE files are identical to those of the WAV file format, but are smaller in size from their compression.

.wma
Windows Media Audio (WMA) is a proprietary format developed by Microsoft. It can be either lossy or lossless. Though not as popular as MP3, some say that lossy WMA tends to outperform MP3 in the area of sound quality, particularly with files encoded at lower bitrates like 64 or 96 Kbps. This performance advantage makes it handy for applications like portable digital audio players, where total play time is limited by a finite amount of internal memory. The Windows Media Audio format features built-in copy protection abilities, unlike MP3, so one is faced with challenges if the file is copy protected. Currently there is no known software that exists which will allow non-licensed users the ability to “crack” the Microsoft DRM (Digital Rights Management) technology other than by using real-time recording to “convert” the file to another of your choosing.

.ogg
OGG refers to the audio file format Ogg Vorbis, that is, Vorbis-encoded audio in an Ogg container. It is a patent and royalty-free, lossy audio compression technology from the Xiph.Org Foundation (www.xiph.org), which is dedicated to open source multimedia standards for the Internet. Ogg Vorbis is considered comparable to AAC and better than MP3 in sound quality as well as providing lower bit rates and smaller file sizes.

.aac
Advanced Audio Coding (AAC), also known as MPEG-2 Part 7, is a digital audio encoding and lossy compression format. It was popularized by Apple computer through its iPod and iTunes Music Store. AAC offers the listener a better and more stable quality than MP3 at equivalent or slightly lower bitrates. AAC files encoded at lower bitrates (like 96 Kbps) sound as good or better than MP3s encoded at higher bitrates (like 128 Kbps) despite their notably smaller size. Thus, one can have smaller file sizes with comparable sound quality to that of MP3.

.mp3
MP3 (MPEG Audio Layer 3) is an audio compression technology that is part of the MPEG-1 and MPEG-2 specifications. MP3 compresses CD-quality sound by a factor of roughly 10, while retaining most of the original fidelity. For example, a 30MB CD track is turned into a 3MB MP3 file. Like other lossy files, MP3 files are much smaller than the recordings they’re made from. That’s because some less-audible information is discarded when the file is made. The encoding bit rate, measured in kilobits per second (kbps), is important to the quality of the sound. In general, the higher the bitrate the better the sound quality.

So now that you know a little more about the audio files you’ve downloaded, the question arises, “Which format do I want my audio files to be in?”

All things considered, more often than not, the MP3 audio file format is the one that you will want to use. From simply conserving storage space on your computer, to ease of transfer to a portable music player, it’s the format of choice. As such, the process of turning different audio files into the MP3 format will be our next task.

Our first step is to determine the desired quality and size of our MP3, as better the quality means bigger the size. This means we must decide at what bit rate, or the number of bits that are conveyed or processed per unit of time, we will reencode the audio file. We will discuss the 112 to 256 kbit/s range, which represents an 8%(1:12) to 18.2%(1:5) compression size of a CD-quality, or WAV, audio file.

In this picture here we see an MP3 file converted at a bitrate of 112kbit/s. Notice the extreme dropoff in the 15KHz range. This bitrate should be avoided, obviously, unless circumstances dictate otherwise, i.e. radio show(podcast) for use on a portable music player of minimal storage space.

This next picture is of a an MP3 file converted at a bitrate of 128kbit/s. It is 9.1% of the original CD quality file size, or a 1:11 ratio. Notice again the sound quality dropoff, though this time in the 17KHz range.

This picture is of an MP3 file converted at a bitrate of 160kbit/s. It is 11.4% of the original CD quality audio file size, or a 1:9 ratio. This bitrate shows marked improvement in sound quality, for if you notice, the results mirror CD quality fairly well, dropping of gradually towards 20KHz.

Now for the 192kbit/s conversion bitrate. Notice the improved quality through the 20KHz range over 160kbit/s. It is 13.7% of the original CD quality audio file size, or a 1:7 ratio. This means an increase of 150% over the 128kbit/s conversion bitrate and 120% over the 160kbit/s conversion bitrate, so increased quality comes with a price. But note, for uploading audio files to the major BitTorrent file-sharing sites like OINK, for instance, this is the minimum bitrate that is deemed acceptable. So for continuity of your audio files this may be your preferred choice, as it strikes a healthy balance between size and quality, not to mention “acceptability.”

The last picture here is of a 256kbit/s convesion bitrate. It is 18.2% of the original CD quality audio file size, or a 1:5 ratio. It is nearly identical through the 17KHz range, and even after that follows the original closely through 21KHz. A dropoff in this range will be imperceptible to to all but only the most fervent of audiophiles. So if you want the best of the best and have ample storage space, this may be your bitrate of choice.

Now that you’ve had a chance to see the difference in bitrate conversions, it’s time for a quick run through on reencoding them. Now keep in mind that you can only go “down” in birate converions, as once audio data is discarded it cannot be recovered.

We’ll use NERO, a popular all-in-one media tool that offers everything from DVD authoring to DATA disc creation.

To begin OPEN NERO.

Then select ENCODE AUDIO FILES from the AUDIO TAB.

The next step is to “DRAG AND DROP” the desired file to convert in the main conversion utility window and select PowerPack Lame MP3 Encoder as the desired “Output file format.”

For the desired settings, i.e. conversion bitrate, select the SETTINGS TAB.

Here it’s time to choose at what what bitrate we wish to convert our audio file, in this case a WAV file as pictured above, into an MP3 at. We’ll select 192kBit for the reasons previously mentioned in terms of minimum acceptability by file-sharing websites.

Click “OK to finish.

And then “GO” to go convert (ha ha).

Presto, you should have successfully converted a WAV file into an MP3 file at a bitrate of 192kbit/s.

Well, we’ve come a long way in this guide, and hopefully you find it useful when both downloading audio files from the internet and then putting them to use. Whether it be simply archving your music or making those “phat beat” discs for the car, this guide should give you an extra dose of good ol’ fashioned know-how. Good luck and have fun.

SOULXTC: “walkin’ the streets of P2P”

Jared Moya
I've been interested in P2P since the early, high-flying days of Napster and KaZaA. I believe that analog copyright laws are ill-suited to the digital age, and that art and culture shouldn't be subject to the whims of international entertainment industry conglomerates. Twitter | Google Plus

Getting to Know Your Audio Files

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