» U2SHN.com » SHN FAQ

taken from the excellent Dig's DMB Archive

What is SHN?
SHN is a file format. SHN is short for "shorten". SHN files are compressed ("shortened") WAV files. SHN uses a lossless compression method.

What is good about the SHN format?
The biggest benefit of SHN is that it uses lossless compression, which means no data is lost when it is compressed. MP3 files are also compressed WAV files, but they use a lossy compression method, which means some of the data in the original WAV file is lost.

SHN files are popular with people who collect recordings of live performances because these people will know what they are getting. SHN files can be copied and passed around endlessly and still maintain the same quality as the original. Compare that to MP3s, which are lower quality to begin with (due to the lossy compression), and are often subject to generational loss -- the quality continues to deteriorate each time they are converted to WAV, ripped from a CD, or downloaded over Napster (files from Napster are often cut off due to either the remote person disconnecting or bugs in old versions of the Napster software).

What is bad about the SHN format?
There are very few bad things you can say about SHN, but there is one particular problem: Even though SHN files are compressed and much smaller than the original WAV files, they are still very large. A typical full concert in SHN format is often over 1 gigabyte. This takes a long time to download even on fast connections. People on modem connections beware -- a 56K download of 1 gigabyte will take over 50 hours to complete.

Can you mail SHN format on CDR if you have a slow net connection?
If you don't have a fast net connection, the best way to get SHN files is good old snail mail. A full concert typically fits on 2 CDRs in SHN format, and although you can't play SHN files directly in your stereo, all you need is a CD burner and some free software to make your own music CDs from the SHNs.

What do I do with them once I've downloaded them?
Since the files are very large, you probably don't want to leave them on your hard disk for long, so the first thing you may want to do is create a data CD-ROM using your favorite CD-writing software. You will also probably want to create an audio CD so that you can listen to the show using your CD player. If you don't have the ability to write CDs, but you want to collect a lot of DMB performances, you should definately consider purchasing a CD burner. Many decent burners are available for $100-$200.

How do I convert SHNs to MP3?
Whoa there, bucko. Before you do this, you need to make sure you are allowed to. Check the info file that came with the SHNs (you downloaded the info file too, right?). Usually there is something in there prohibiting you from converting the SHNs to MP3 format. Even if there is no such statement in the info file, you really should not convert the SHNs to MP3, because of the loss of quality, and the fact that once MP3s of a show start to be created, it becomes more difficult to find original, non-mp3-sourced copies of the show. If you do create MP3s from the SHNs, you should never distribute them (don't share them on Napster!), and you should never, ever use your MP3s to create a music CD.

How do I convert SHNs to WAV?
Any of the SHN software listed at the bottom of this page should be able to do this. Exactly how this is done varies by software, so please check your software's documentation for instructions.

How do I make CDs from SHNs?
First ask yourself: what kind of CD do you want? A music CD that you can listen to, or a CD-ROM with archive copies of the SHN files? There is good reason to do both, especially if you want to trade your show with others.

How do I make a music CD from SHNs?
First, you need to convert the SHNs to WAV files. Then, use your favorite CD writing software to burn a music CD from the WAV files. We list our preferred bruning and extraction tools on our software page.

How do I make a data CD-ROM from SHNs?
A data CD-ROM has a couple of advantages over a music CD. First, you can put the info and md5 files on the CD along with your SHN files, thereby preserving the source info and authenticity info to go along with your SHN files. Second, you can make perfect copies of data from a CD-ROM easily. To make a copy of an audio CD, your computer will have to use an audio extraction process which is often not perfect. The extraction process is where clicking and popping sounds are often introduced into WAV files.

OK, enough about why you would want to make data CD-ROMs -- how do you do it? Well, you just need to create a data CD-ROM using your favorite CD burning software. Of course the process varies with each different software product, but it's usually a matter of just selecting all of the SHN files (and associated md5 and info files), then creating the CD.

What is MD5?
MD5 is a type of checksum that is used to verify that a file is unaltered. It can be used with any type of file, and is very popular in conjunction with SHN files, since the whole intent of SHN is to have an unaltered copy of the original recording. SHN files will normally have an MD5 file associated with them. An MD5 file is a very small text file containing the MD5 checksums of each of the SHN files. Some of the software listed at the bottom of this page includes the ability to verify that SHN files match the MD5 checksums, so that you will know that you have an unaltered copy of a performance.

Can I listen to SHN files in Winamp?
Yes, you can do this with the SHN Winamp Plugin available at Etree.org. Keep in mind though, that, unlike MP3s, SHNs were not designed to be played directly, so this may not work as well as playing MP3s in Winamp.