Declipping/Peak Limit Restoration

dallasjustice

Member Sponsor
Apr 12, 2011
2,067
8
0
Dallas, Texas
I want to know whether this is something which can be done with any success. I tried a vst plugin called perfect declipper and it sucked. I've heard a few demos of the izoptope rx declipper which sounds much better to me. Has anyone figured out the best way to "restore" those lost dynamic peaks due to the loudness wars?

The problem is that there's some great music which is unlistenable due to crushed dynamics. My theory about fixing them is best explained by Bob Dylan.
"When you've got nothing, you've got nothing to lose."

Michael.
 
Last edited:

amirm

Banned
Apr 2, 2010
15,813
37
0
Seattle, WA
I have not tested any of this but did look at the web page for perfect declipper and it goes way outside of what is possible to reconstruct the waveform. I think the right solution only attempts to restore small amount of clipping. More than that may be akin to guessing where the stock market will go tomorrow :).

A side-effect of any such fix is that the levels will have to be pulled down to create enough headroom for reconstructed waveform. As such, the comparison should be done with the levels re-adjusted to be the same as the original in analog domain.
 

dallasjustice

Member Sponsor
Apr 12, 2011
2,067
8
0
Dallas, Texas
Yes. It seems like I could expect to see a -6db or so reduction. I noticed harman has the clari-fi declipper. Is that just for car stereos? Why is it pateneted?

I have not tested any of this but did look at the web page for perfect declipper and it goes way outside of what is possible to reconstruct the waveform. I think the right solution only attempts to restore small amount of clipping. More than that may be akin to guessing where the stock market will go tomorrow :).

A side-effect of any such fix is that the levels will have to be pulled down to create enough headroom for reconstructed waveform. As such, the comparison should be done with the levels re-adjusted to be the same as the original in analog domain.
 

Tam Lin

Well-Known Member
Mar 20, 2011
96
36
923
79
North Texas
A side-effect of any such fix is that the levels will have to be pulled down to create enough headroom for reconstructed waveform.

But when you pull the level down to create headroom you lose resolution and add quantization noise to the entire track because you have cut off the least significant bits of every sample.
 

dallasjustice

Member Sponsor
Apr 12, 2011
2,067
8
0
Dallas, Texas
But when you pull the level down to create headroom you lose resolution and add quantization noise to the entire track because you have cut off the least significant bits of every sample.

If you didn't dither, that would be true. I am talking about tracks with very limited DR. So I'm not too concerned about "losing" any bits. They aren't being used anyway.
 

amirm

Banned
Apr 2, 2010
15,813
37
0
Seattle, WA
But when you pull the level down to create headroom you lose resolution and add quantization noise to the entire track because you have cut off the least significant bits of every sample.

Presumably the application here is on compressed soundtracks so losing resolution is the least of our worries :).

Clipping is far more of a problem than resolution loss anyway.
 

Bruce B

WBF Founding Member, Pro Audio Production Member
Apr 25, 2010
7,006
512
1,740
Snohomish, WA
www.pugetsoundstudios.com
If you lost part of the waveform due to clipping, you will never get it back. Unless you went back to the original source, you (and software restoration tools) are just making a wild ass guess!
Same with compression.
 

amirm

Banned
Apr 2, 2010
15,813
37
0
Seattle, WA
Hi Bruce. If the clipped section is highly correlated to what is before clipping, then reconstruction can be pretty good. Here is an extreme example done manually in photography:

Original:


Reconstructed:


In this case the background was predictable so it was expanded. And the wing tip was also so and same treatment has gone there.

Of course the above is the work of a human. Computer version is harder although Photoshop's delete tool works reasonably well in recreating what is not there.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing