Strange wav files. What filter can I use?

I am working currently on a few projects connected with audio f开发者_运维知识库iles recognition. However one type of files creates many problems.

From Audacity:

Are there any known filters/algorithms which can cope with this type of files and make them "normal" ?

The sound must be heavily distorted.

A possible solution to restore the waveform is to apply a high pass filter at 30hz. If you only care about voice you can then apply a low pass at 10khz to improve the thrashing that the distortion has introduced to the sound.

Note though that there is a possibility that this wav sound has a special encoding. In that case you need to convert or load it correctly instead of trying to fix the sound.