This document explains some basic concepts about file compression. This is necessary because audio files normally are quite big and not handy for download

First of all we must differenciate between compression with losses and without losses. Today the most populer audio format is mp3. This is MPEG Audio layer 3 compression. This technology is quite old but is is the most used even when there exist better technologies today like AAC (apples sort of MPEG 4 used in Itunes and therefore only available in the itunes player application)

The quality is measured in kb/s (kilobit per second) that means how many data is stored to play one second of music. Very strong compression is smaller than 64 kb/s and you should not go below that when you want that your audience can grasp the content.

Trackseller was designed to sell all file sizes and I personally think that CD audio quality is not the same as mp3 but I admit that 192 kb/s mp3 sounds quite good.

So here Is my proposal for mp3 : When you want to sell your files in mp3 use 256 kb/s compression rate, that is nearly no difference to an original file in CD quality.

The second way to compress audio files is to take a regular compression utility and compress an audio file as if it was a regular binary file.

I have done that with several compression utilities and found out that on they are fast or slow and compress better or worse.

I used the famous and most widely used winzip utility on a file of 219 MB.

The result was a zip file with 196 MB

Then I tested the BZ2 format, quite often used in the LINUX world and recieved a file size of : 186 MB

The next test was 256 kb/s mp3 file that yielded a file size of : 39 MB

The best results were obtained using winrar that is available here. It compresses the 219 MB down to 125 MB and that in an even short time

So this is what I propose to you when you think about compression :

First create a storage space where you store all your files that you want to sell locally.

Then download the free evaluation copy of winrar and compress all files.

Upload the files to your webserver and register them with trackseller.

The point about winrar is that the compressing mechanism is not licensed to other software manufacturers (that means you will not get a free compressor that uses the rar compression algorithm (no ? send me a mail to office [at] trackseller.com )).

But there exist many free compression utilities that can open the rar archive type (that is important for your customers!!!)

So you can compress once using the free evaluation copy, you upload all the files to trackseller, your customers can open the archives for free because they may use a free archive utility

Ok, winrar is only 29 $, so you may also buy it, when you make more use of it. It really is good.

The philosophy behind trackseller is that it works like an online record store, but you download the record, that means, all the data for me. When you think, 256 kb/s mp3 is ok and your customers will like it and pay for it, just do it, you know, trackseller sells everything that smells like a file.

If you really want to use lossy compression, Ogg Vorbisis said to be of better quality than MP3

There also exists a promising new trend that is FLAC which is a FREE! lossless audio compressor that compresses to 50% of the original size without loss of quality.

I tested it and it was not as good as winrar. The most important benefit of FLAC is, that it is a lossless format that is streamable. But unfortunately trackseller is a download site and does not support streaming