Shorten (.shn) Technology and CD-R Burning 

I wrote this page to help others along the path. When I first got into CD-R burning using a PC, it took me a little while before I really understood how to record music discs in the best possible way. If you're new to this sort of thing, this doc will help.
 

First Things First...

Here are some terms and concepts you should be aware of:

  1. File Formats/Extensions: - Under the Windows operating system, every file has a 3-digit file extension which the operating system uses to identify what type a file is and how that file should be treated. Here are some music-related file types that you should be familiar with:

    • .cda - CD Audio Tracks (also called "audio files" for short) - Regular music compact discs like Pink Floyd's "Dark Side of the Moon" contain files with this kind of format. Obviously, audio discs were originally designed to be played by stereo-component CD players which employ sophisticated hardware.

      Audio discs, however, can also be played by your computer, but PCs have different kinds of hardware than stereo-component CD players. To bridge the gap between these different hardware components, most of the work needed to play audio discs on a PC is done using software. In short, the software mimicks or emulates the hardware of a regular CD player. That's why the software-simulated CD player's performance is usually not as good as if you just played the CD on a regular CD player. Hardware is fast. Software is slow.

    • .wav - Wave Files - audio files in a format that your PC can treat like other data files.

    • .shn - Shorten Files, often called "shin" files, are lossless compressed wave files. Lossless means that even though the wave file has been compressed, the original wave information can be "regenerated" if need be.

      Please Note: The process of going from .shn to .wav is called decompression. That is, we decompress .shn files to wave format.

    • .mp3 files, on the other hand, are "lossy" compressed wave files. Lossy means that much of the original wave information gets lost as a result of the compression process and cannot be "regenerated." This is the main gripe among RoIO traders and audiophiles about this kind of music format - digital information gets lost and cannot be retrieved. This loss of digital information results in an inferior sound quality.

    • .md5 - File Integrity Signature List - the critical checksum file used to verify that wave files compressed properly to shorten format. (These types of files are created as a kind of by-product when converting wave files to shorten format.)

  2. Burn - To burn a CD means to copy a CD's data onto a CD-R. There are two types of burns:

    • data burns (also called "binary to binary" burns) - e.g. when burning .shn files, the format stays the same on the burned media. That is, the files are copied exactly, both the source and target media have the same bit configuration.

    • audio or music burns - e.g. when burning .wav files, the format changes to .cda on the burned media. You're basically making an audio disc with this type of burn. A file format conversion takes place, so the source and target media will differ - the source being .wav and the target being .cda. This conversion is needed so you can play the disc on a regular stereo-component CD player.

  3. Ripp - Ripping is the process of reading an audio CD's information and converting it to .wav format. The wave files are copied onto your computer's hard drive during the process. Ripping is also sometimes referred to as grabbing. Think of ripping as transforming audio files (.cda files) to wave files (.wav files).

    Please Note: This is a non-destructive process. That is, the original audio files are left intact while new files are generated as a result of the ripping process. Shinning wave files (or compressing wave files) is also a non-destructive process.


The tools of the "trade"...

  1. EAC - Exact Audio Copy - the best audio "grabber/ripper" in cyber-land and it's totally free. EAC's homepage is located at: www.exactaudiocopy.de.

  2. mkwACT - The "Michael K. Weise" Audio Compression Tool is used to convert wave files to shorten format and vice versa. This tool creates the necessary .md5 files needed to perform verifications. Be sure to check out: www.etree.org for more info about this tool and free downloads. etree.org also has info about EAC.

  3. Easy CD Creator (or some similar CD-R burning software) can be used to do the actual copying (burning) of CDs and CD-Rs. Burning a CD is no big deal really. What I mean by this is that very few errors occur during the burning process, that's why we can burn at such high speeds (32x, 40x, 48x, and so on).

Discussion...

In my mind, it all comes down to EAC. That is, getting a good ripp is the most important step when it comes to copying audio tracks successfully. It goes without saying that your source disc must be clean and free of defects.

The beautiful thing about EAC is that it does a lot of error checking to make sure that it copies and converts audio files properly. Most other commercial rippers do not implement error checking well. Hence, if you use a program other than EAC, many errors will most likely be introduced into the target media as a result of the ripping process. That is, the resultant wave files will contain errors which will reduce the sound quality of the tracks. This, of course, spells disaster for the serious RoIO trader. If repeated bad ripps occur, digital degradation of the tracks increases and the sound files become worthless over time.

The conversion from CD audio tracks to wave format is necessary because your PC cannot "work with" audio files directly. What I mean here is that you cannot copy audio files using a tool like Windows Explorer. However, once audio files have been converted to wave format, your PC can then treat these files like any other PC file (.doc, .xls, .htm, etc.). The important side-effect being that you can then use programs like Windows Explorer to cut, copy, and paste your waves files. You'll want to move them around and in some cases rename them and so on.

Enter mkwACT. This tool simply "caputures" the ripp. That is, mkwACT transforms (compresses) the wave files to shorten format and in doing so, generates the precious checksum file (.md5) also called the file itegrity signature list. It is this checksum file that is used to verify whether or not you have the correct SHN files. This is a critical point.

You see, when you copy SHN files from a CD-R to your hard drive, you'll want to verify that the copy procedure was done properly (i.e. that the copy didn't corrupt the SHN files somehow.) Once the files have been transferred to your hard drive, you then use the MD5 file to perform a checksum (verfication operation) on the SHN files. If the verification process comes back "succussful" this means that the SHN files were copied on to your hard drive intact - no data was lost. In other words, your copy operation (using Windows Explorer) was succussful.

A Side Note: The MD5 checksum file is needed to decompress the SHN files to wave format so be sure you copy this file as well when copying SHN files on to your hard drive from a CD-R.

Now here is a critical point: Once a disc has been converted to shorten format, there is never any need to use EAC again for that disc! In fact, that is the whole point of the mkwACT tool. It freezes the ripp and generates a checksum in doing so. As long as you have your master .shn and .md5 files safe somewhere, you can always burn audio discs from them. This keeps your music safe and lossless.

Check it out: If we receive a shorten disc in the mail and want to burn it we have two options:

  1. We can simply copy the disc exactly using a "data-burn" and send it to your friend in the mail. (Be sure to copy the .md5 checksum file, the shins are useless without it.)

  2. We can also make an audio CD from the .shns, but first, we need to decompress the shorten files to wave format and then perform a "music-burn."

    As you can see, EAC is not involved in either of these two steps. We only need to ripp once. And that is really the whole point of the "shin" game. Once you find the best source possible for a show, EAC it, then "shin" it to preserve the EAC ripp and the wave data.


The Ripping-Burning Process...

Using the following diagram, let's trace the two different paths (steps 1a, 2a, 3a, 4a and steps 1b, 2b) to accomplish our ripping/burning goals.

The Ripping-Burning Process

Path A: Create a .shn disc from a CD Audio disc...

  1. Insert the audio disc in your CD-ROM player, then Ripp the audio files using EAC.
  2. Compress the wave files to shorten format using mkwACT. (The .md5 file will be created during this process.)
  3. Verify that the .shn files compressed without error.
  4. Perform a data-burn using Easy CD Creator or some other similar kind of burning software to copy the .shn and .md5 files. It doesn't matter if you use DAO (Disc-at-Once) or TAO (Track-at-Once) for a data-burn, but I suspect that TAO is the better option.

Path B: Create a CD Audio disc from a .shn disc...

  1. Copy the SHN files and MD5 file from your CD-R to your hard drive using Windows Explorer. Then decompress the .shn files to wave format using mkwACT.
  2. Perform a music-burn using Easy CD Creator or some other similar kind of burning software. In this case, it is imperative that you use the DAO (Disc-at-Once) option, not TAO (Track-at-Once). If you use TAO, you will not have smooth transitions between tracks. The reason being is that during TAO the CD laser is lifted between each track which creats a brief 2 second gap upon playback. (Very bad.)

    As the above diagram shows, a second option here is to burn the wave files using a data-burn, but this is not terribly useful unless you just want to play the disc on your PC.

One more thing... From the diagram, you can see that you can go from .cda to .wav to .cda (step 1a to step 2b). This is how you'd just copy an audio disc. (Sorry for stating the obvious.)
 

In Summary:

To convert an audio disc to shorten format, we ripp once with EAC, compress with mkwACT, and perform a data-burn with Easy CD Creator or other burning software. To reiterate, once audio files have been converted to wave format and the waves have been compressed to shorten format, there is never any need to ripp the audio tracks again. That's where the beauty lies in this whole schema - we don't have to worry about introducing new ripping errors because we only ripp once and we ripp with EAC.

To convert shorten files to CD audio tracks: Decompress the shorten files to wave format using mkwACT, and burn using Easy CD Creator. This time, however, be sure to burn the disc as a music-burn with the DAO option turned on. And voila, that's it! Your audio disc is ready to be played on either your stereo or on your PC.
 

Closing:

I hope this little article helps demystify some of the jargon and concepts needed to become a productive member of the trading community. Thanks very much and be well.

Gabriel Perry
Boulder, Colorado
www.flupe.com   (Your source for the best online guitar lessons.)