This has come up a few times on the Audacity4Blind mailing list, so I thought I’d write a plug-in for it.
The issue is to show the peak amplitude of a track.
There is a “trick” for getting the peak amplitude using the Amplify effect, but it would probably be easier to just have a tool in the Analyze menu that will give a direct reading of the peak amplitude, so here is such a tool.
show-amplitude.ny (2.4 KB)
To install the plug-in, place the show-amplitude.ny file in the Plug-Ins folder inside the Audacity installation folder.
- On Windows computers, this is usually at C:Program FilesAudacity. On 64-bit Windows this directory will be “Program Files (x86)” then as appropriate.
- On Mac OS X, it is usually under /Applications.
- On Linux this is usually /usr/share/audacity/ if you installed a repository package of Audacity or /usr/local/share/audacity if you compiled Audacity. Note: You must log in as root to access /usr. Repository packages of Audacity may overwrite this folder. An easier alternative may be to create ~/.audacity-files/plug-ins/ in your home folder (the “.” in the path means it is a hidden folder).
Restart Audacity, then the plug-ins will appear as "Amplitude…" underneath the divider in the “Analyze” menus.
To use the plug-in, Select the audio that you want to analyze, then from the Analyze menu select “Amplitude…”
There are two available controls:
Show amplitude as: [choice: Peak dB, Peak Linear, or dB and Linear] The default is to show the peak amplitude in both dB and as a linear value.
Decimal Places: [0 to 5] The default is 2 decimal places.
Note that setting decimal places to zero is not likely to be useful when displaying the amplitude on a linear scale (0 to 1).
If the peak level is equal or greater than 0 dB, a warning will be shown to alert the user that the audio may be clipped.
This plug-in can also be customised. Open the show-amplitude.ny file in a text editor for details.
On Windows it is not possible to copy the display text. If you need to copy the display text, use the “Debug” button instead of the “OK” button to run the plug-in. When the display message shows, activate the “OK” button and a “debug window” will then appear with the same text as the display message. The text can be copied from the debug window in the usual way (Ctrl+A to select the text them Ctrl+C to copy).