There are two ways to change a file in MP3 Diags: saving ID3V2 tags in the
tag editor and applying a "transformation" (or a "transformation list"); there are some configuration settings that determine what happens with the files when transformations are applied, and, because saving from the tag editor is treated internally as just another transformation, these settings also concern saving ID3V2. (Well, there's also a third way to change files, the
normalization, but that's done by an external program, so it's a different story. All that MP3 Diags does with the files when asked to do a normalization is rescan them after calling the external program.)
There are more than 20 transformations that can be applied to an MP3 file or to a group of files. There are 2 ways to apply transformations:
- Pick a single transformation from the menu that opens when clicking on the "Apply a single transformation" button
- Click on one of the four buttons corresponding to the four "Custom transformation lists"
Normally transformations are applied to all the files that are visible (well, or can be made visible by using the vertical scrollbar.) However, if you press SHIFT while clicking, the transformations apply only to the files that are selected. The same can be achieved by clicking on the right button after clicking on the left one and before releasing it. This is similar to "rocker gestures" in web browsers, about which I only found out (believe it or not) some time after implementing this functionality in MP3 Diags. For the "single transformation button", opening the menu with the left button and making the selection with the right button does the trick. (I assume that left-handed people already know that "left is right" when it comes to mouse buttons.)
You can get an idea about what the "custom transformation lists" are good for by looking at the default values (either by holding the mouse over the buttons, to show tooltips, or by going to the
configuration.) The point is that for some of the 20+ transformations it makes sense to apply them sequentially to a file to achieve a "higher goal". In the default configuration, the first custom button fixes the audio part of a file, the second takes care of the ID3V2 tag, while the third cleans up the rest of the file.
So why use three lists when one could do everything? Well, because I feel more comfortable this way. Personally, I like to review the effects of some changes before going any further, and this grouping seems to work best for me. Anyway, the fourth list is empty by default, and you can configure it, as well as the first three, to do whatever you want.
Several points need to be made about the custom transformation lists:
- You shoudln't blindly use the default lists. Try to understand what each transformation does and how it may affect your files.
- Review the order in which transformations get applied. Sometimes it doesn't matter but usually it does.
- Look at what the other transformations are doing, and change the lists to better suit your needs. Then test your changes.
- The same transformation may be added multiple times, but usually there's no need for such a thing.
There are a number of files involved in applying a transformation to a file. Besides the original file and the modified one, "comparison" files may be created in some cases and "temporary" files may be created too, their name containing the name of the transformation that created them. These are disabled by default, but may be enabled in the
configuration dialog to gain a better understanding of what is happening, or for debug purposes.