Repair Effect

From Audacity Manual

Jump to: navigation, search

Flag_of_Holland_small.png

The Repair effect removes a very short selection of damaged or destroyed audio, replacing it with an estimated section of audio based on what is happening either side of the selection. It may be used for example to repair a click on a vinyl record, or a tape drop-out.
Accessed by: Effect Menu > Repair

Requirements

The Repair effect can only be used on selection regions up to 128 samples long (for most audio, only a few thousandths of a second). Above this length, it becomes too hard to guess what should be going on in the section under repair. You will get an error message if you select too much audio to try and repair. In general, the shorter the section of audio you select to repair, the better the results will be.

The Repair effect is unusual because it requires there to be audio outside the selection on at least one side of the section to be repaired. Examining this audio lets Audacity interpolate (make an informed guess about) the bad section. If the surrounding audio in the track is very short or non-existent there may not be enough information to make the interpolation, and an error message will be shown. For example, it is not possible to select a region up to 128 samples long in one track, paste or duplicate it into a new empty track and then repair it, because there will then be no audio either side of the region to examine.


Usage

  1. Select the damaged region of audio. Zoom in close and only select the shortest possible piece of audio that has to be replaced.
  2. Select Effect > Repair to replace the selected audio with the repaired audio.
  3. Zoom back out (or grab the handle on the horizontal scrollbar and drag leftwards), click a few seconds before the region you were repairing, and play from there to hear if the repair sounds OK. If not, click Edit > Undo and try a different selection. Include a little more on either side of the problem if the original damage is still obvious, or less if the repaired region sounds different, but incorrect.

Notes

  • When trying to repair a section of audio that has been clipped (got too loud), use Effect > Amplify... first to make the entire track quieter. This gives some headroom for Repair effect to work in.
  • If only one channel of a stereo track is damaged, you can repair only the relevant channel by clicking on the Track Drop-Down Menu and selecting "Split Stereo Track". After repairing the single channel, you can rejoin the channels by using "Make Stereo Track" in the upper track's Track Drop-Down Menu.
Views
Help Location