Basic Operation Before you begin using MP3 Trimmer, we recommend that you read at least this section. The most basic functionality - trimming an MP3 file - is described here. When you feel comfortable with the basic functionality you may head on to the other sections. Loading an MP3 file Launch MP3 Trimmer and select 'File->Open new MP3' (Cmd-O), or drop the file onto the MP3 Trimmer main window (if you have registered MP3 Trimmer, you can also drop the MP3 file on the MP3 Trimmer icon in the OSX Dock). You may also drag an MP3 file directly from the iTunes window to MP3 Trimmer window. MP3 Trimmer will validate all frames in the MP3 file (with a large MP3 file this can take a while). If the file is damaged, an alert pops up and offers to repair it (if possible). A new, repaired file will be created.
Main window overview: ![]() MP3 Information area 1 This shows useful Information on the file:
Playback controls 2
Trim points The trim points are used to select the beginning and end of the part you wish to keep in the MP3-file. There are two different trim points; the In-point and the Out-point. When you first load an MP3 file, the In-point and Out-points are automatically set to the beginning and end of the file. Setting the In-point 4 ![]() The In-point controls are at the left side of the main window. Click the "Set" button to mark the In-point. The In-point time display will show the In-point time, the "Set"-button changes to "Clear", and the locator changes to green indicating it now marks the In-point. Auditioning/adjusting the In-point ![]() Click the "Try" button to listen to the current trim point. If the "Try" button is disabled (greyed out), no In-point has been set (see above). You can also initiate the audition window by pressing Cmd-T when you are near a trim point (the closest trim point will be the one auditioned). The test clip in the audition window will let you listen to the trim point (100% frame accurate) as well as audio fades and/or gain adjustments. When the audition window is up, the following keycommands are available:
An equalizer display allows you to monitor gain adjustments visually. If you wish to relisten to your clip, just drag the slider to the beginning, or press the Enter key. You can adjust the trim point. Stop the test and press the + or - buttons located at each side of the "Try" button. Each click moves the trim point one frame forward or backward. Setting the Out-point 5 The Out-point marks where the clip you wish to keep will end. The procedure is identical to the way you set the In-point. When the Out-point is set, the locator will change to red, indicating that it now marks the Out-point. Applying fade-in and fade-out 6 ![]() By clicking this button you enable the buttons to control the length of the fade-in and fade-out respectively. The length can be set in intervals of half a second (or 0.1 sec by holding the Shift-key down while clicking) and the longest possible fade time is 45 seconds. To listen to the effect of the fade-in or fade-out just press the desired Try-button. If the Try-button is disabled, no trim point has been set. You may easily select the type of fade curve to use by clicking on the fade curve symbols. The fade curves determines how fast and intense the fade action should be - you may try them out with the Audition window to find the most suitable one. Adjusting the over all gain 7 ![]() The Gain Adjust operation actually adjust the output gain of each frame, whichh is nothing like the 'adjust gain for this song' parameters in many audio playback devices/applications (they may only work for that specific device/application). The gain adjust performed by MP3 Trimmer is written to each and every frame of the song, which will allow it to work on all playback devices (hardware / software). It may seem pretty permanent, but you can always change the gain in opposite direction with no quality-loss (we're dealing with it binary here). A word of advice: It's easy to distort the audio if too much gain is applied. Use the audition feature to listen to the effect. In other words - use your ears....
Clearing a trim point ![]() To clear a trim point, simply position the locator at the trim point again (drag the locator until it stops in either direction). Now, the color of the locator will change and the Set-button will change to a Clear-button. Pressing it will remove the trim point. Saving your trim selection When you're satisfied with your trim settings - and have auditioned both the In- and Out-point - you can save your selection as a new MP3 file. This process is done by copying the selected frames, which means no re-encoding is done. Not even the fade parts are re-encoded, instead this is done by changing specific gain values inside the audio frames. Select 'File->Save trim selection' (Cmd-S) to bring up the Save dialog. Choose the desired location and name your file. If you have checked 'Create filename' in the Preferences, MP3 Trimmer will create a filename for you, based on the filenaming template chosen and the ID3 tag information in the file (if present). In addition, if you checked the option 'Keep ID3 tag' 8 (enabled if ID3 tag data is present) the ID3 tag data will be preserved in the saved file. After a few seconds (on an average sized MP3) your new, edited MP3 file has been saved! And with exactly the same audio quality as the original file...
Move the In-point to the Out-point With both In-point and Out-point set, you can easily exchange the current In-point with the Out-point (the old Out-point will be cleared) by pressing Cmd-M (in the Tools menu). This is a handy short-cut when you're extracting multiple songs from one large MP3 file. |