^ What's the point?
^ Basic steps
^ Detection parameters
^ Fixing options

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UnDistort Audio File

UnDistort Audio File is a powerful audio file repair tool, to fix pops, cracks, glitches and fix skips in audio files.
It does not remove humm or hiss for example, only sharp changes in the audio.

  • Automatically detect distortions in audio files with adjustable detection parameters
  • Display each detected glitch one-by-one visually on a sample display
  • Fix all distortions automatically or manually one-by-one
  • Apply the frequencies that are present before the detected distortion to the fix
  • Save the fixed audio file in MP3, Opus, Flac or WAV format
  • Multi-channel audio files are supported
UnDistort Audio File is a shareware software. Unregistered version is a fully functional trial version that adds beeps in saved audio files. If you like this software please register.

Basic steps
  • Select an input file and click "Load".
  • Click "Run auto calibration", the "Treshold" specifies how many distortions to detect minimally.
  • Click "Find distortions". If there are too many detections, adjust the "Detecting options" parameters and click "Find distortions" again.
  • Click "Next distortion" (multiple times) and check the detection results.
  • To fix all detected distortions automatically click "Fix all detected distortions" (not recommended).
To fix the detected distortions 2 ways are possible:
  • Go through all the detected distortions one-by-one and either fix or remove the detected distortion. If removing them, after removing all not needed detected distortions, click "Fix all detected distortions", this will apply the fix for all the distortions that were not removed. Click "Save" to save the new audio file with the fixed distortions.
  • Or if clicking on "Fix this distortion" for all the distortions, if finished, click "Save" to save the new audio file with the manually fixed distortions.
  • The audio samples are only modified if clicking on "Fix all detected distortions" or on "Fix this distortion".

Detection parameters

Use the sensitivity slider to quickly change the 2 most important parameters for detection. 100% is usable for audio files with average volume.
Set "Treshold" to specify how many distortions to detect minimally when using "Run auto calibration". When loading an audio file "Run auto calibration" should be the first thing to do. If there are only a couple of clicks for example in the audio, set "Treshold" to little above the number of clicks.
To fine tune the detection the parameters are as follows:
  • Check sample difference: spcifies the sample difference of one sample after the next, that triggers a check whether it is a sharp change occuring.
  • Forward check sample count: specifes how many samples to check after the trigger, to decide whether it is a sharp change really.
  • Forward check sample sum difference: specifes the average sum of the "Forward check sample count" samples' values. If the calculated average is higher than this value a detection start point is detected.
  • Check sample difference continue: specifes the maximal difference of the first detected sample's value, where the distortion started, and the sample's value that's the last sample value of the distorted part (where the distortions ends). So if the sample value is in this range it is considered as an ending point of the distortion.
  • Max. distortion length: maximal distortion size in samples to treat as a detected distortion. Detected distortions that are longer will be not treated as a detected distortion and will be skipped.

Fixing options
  • Waveform steepness scan length: number of samples to average when calculating the steepness of the start and end of the distortion. The suggested fix's shape is determined from the calculated steepness. Higher values result a more average fix shape, lower this value to have a flatter fix.
  • Start smpl and End smpl: if the detection is not precise, use these values to adjust the detection's start and end point. Only usable when doing manual fixing.
  • FFT modulation: 256 sample values are processed just before the starting point and their frequency distribution is calculated with an FFT, the slider specifies how much to apply these frequencies to the fix.
If using the "Fix all detected distortions" functionality all fixes will use the "Waveform steepness scan length" and "FFT modulation" values. If fixing the detected distortions one-by-one manually these values can be changed to apply the fix every time with specific values.