Eliminating clipping from overloaded audio
Clipping occurs when a piece of equipment or a medium carrying a signal is unable to handle a high level presented at its input, and will usually be heard as a harsh distortion that increases in intensity as the clipping becomes heavier. In all cases of clipping, it is the portions of the waveform near its extremities that are affected, while portions of the waveform closer to zero are unaffected. Examples of clipping include:
- Digital clipping
The signal contains many false samples. Viewing the audio waveform would reveal 'flat tops', at which points the genuine signal is destroyed and replaced by false samples at the maximum amplitude.
- Clipping of analogue equipment and media
There are many different types of analogue clipping. These will usually be less obvious than digital clipping, with the hard edges visible in the former case replaced by a more rounded profile.
Declip-2 replaces and greatly improves upon the original Declip algorithm supplied up until CEDAR Cambridge V10. As before, the process identifies and removes most instances of clipping in a single real- time pass but now, with its new, adaptive Auto mode (which identifies the clipping point and even tracks changes in the amplitude at which clipping occurs) eliminating the distortion and restoring the original dynamic range of the signal is as simple as clicking on the Auto button to obtain optimum results. Manual controls are also supplied for tweaking the results if desired, and multiple display modes can then help you to analyse the audio correctly.
Declip 2 is a further development based upon the Sparse Audio Declipper algorithms developed by Inria - Panama research team.