Zack Rippy

This is certainly not a definitive guide to archiving or storing digital audio. This is just an overview of what I do with my library.

Since I first started storing music digitally, MP3 has been my format of choice. It is not open source, but a.) it is the ubiquitous digital audio format and b.) I don’t care. Everything can play it for the most part. That cannot be said of closed format like Apple’s M4A and Microsoft’s WMA.

MP3 is a lossy format, meaning that data is actually sacrificed to decrease file sizes when audio is encoded. There is naturally a trade off between file size and audio quality. Audio can be encoded at different bitrates. Standard, uncompressed audio has a bitrate of 1440kbps. There are three basic kinds of mp3 encoding:

• Constant Bitrate (CBR) - maintains a constant bitrate throughout the entire file. There is no variation.
• Average Bitrate (ABR) - allows the encoder to fluctuate the bitrate, but with goal of an overall average bitrate
• Variable Bitrate (VBR) - this method allows the encoder great flexibility to attempt optimized compression

Traditionally, I have always encoded my mp3’s at a constant 256kbps bitrate using the LAME encoder. LAME is my preferred compressor for mp3’s. This process cuts the file size in a sixth (approximately) and maintains very good-sounding audio.

Due to relatively recent changes in the LAME encoder, I have started using variable bitrate encoding for my mp3’s. There are a couple reasons for this. First of all, variable bitrate allows the encoder to dynamically adjust the bitrate for different audio frames. Complex musical segments are encoded at a much higher bitrate, while vocal audio and less complex data is encoded at a lower bitrate.

My new encoding process of choice is to use LAME with the -V 0 –vbr-new switches. This tells the encoder to use variable bitrate encoding level 0 (highest) using the new, faster encoding scheme. LAME will create a file with a bitrate that varies between 220 and 260 kbps. I have seen a little bit of saving in disk space and the quaility is just as good, if not better, than my old constant bitrate process. If you want to see how well your encoder is dealing with your audio, I highly recommend EncSpot. It will analyze mp3 files and present you with very useful information.

Note: I still recommend using a constant bitrate when encoding audio for podcasts. I have observed strange results when podcast audio is encoded at a variable bitrate.

There is another audio format that I am loving lately, and that is flac. FLAC (free lossless audio compressor) is just what it sounds like - a free (open source) lossless audio compressor. I know, it boggles the mind.

Lossless encoders compress audio with no loss of audio data (if done correctly). This presents a perfect format for digitally archiving audio. MP3 is not a desirable option for this because actual audio information is discarded, meaning you can never return to the exact, original state. I have started archiving my rare, irreplaceable CD’s in flac format. I already have around 300GB of flac audio of various live concerts, etc. Some bands allow fans to record their shows and flac is the format of choice for exchanging these shows online. In fact, if the major audio applications supported flac natively, I would probably replace all my mp3’s with .flac counterparts.

Finally, the application used for actually ripping audio from CD’s is very important. Over the years, I have found Exact Audio Copy to be the most accurate audio ripper on the market. It can also be used to pass custom parameters to the compressor of your choice (LAME/MP3 or flac in my case) to rip and compress all at once for you. I will post a simple walk-through soon on configuring EAC for the most accurate, error-free rips.

Digital audio is unquestionably where music is going (has gone). I’d hate to see CD’s and physical medial disappear completely, but there is no doubt that people want the convenience of portable, digital music. This is how I deal with mine. What about you? I’d love to hear how you store your digital music.

Info:

LAME @ Hydrogen Audio - A good overview of LAME
MP3 @ Wikipedia
FLAC @ Wikipedia

Download

LAME Encoder
FLAC Encoder
Exact Audio Copy
EncSpot

This entry was posted on Tuesday, January 15th, 2008 at 10:20 am and is filed under Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.