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Subject:clipped peaks
Posted by: brianejones
Date:9/8/2000 12:50:00 PM

I have a recording which peaks are clipped that are not
above -20db.

What can I do to eliminate this or repair the peaks within
Forge? I tried the parametric EQ, and tried resampling the
sound (which reduced the noise generated by the clipping,
but the sound quality was degraded considerably.

Regards,

Brian

Subject:Re: clipped peaks
Reply by: ATP
Date:9/8/2000 8:48:00 PM

Maybe you could try SF Noise Reduction 2.0. It's a DirectX plug-in
that also installs a "Clipped Peak Restoration" plug-in. That might
help you. I don't know however, since I've never used that particular
feature.

Brian E. Jones wrote:
>>I have a recording which peaks are clipped that are not
>>above -20db.
>>
>>What can I do to eliminate this or repair the peaks within
>>Forge? I tried the parametric EQ, and tried resampling the
>>sound (which reduced the noise generated by the clipping,
>>but the sound quality was degraded considerably.
>>
>>Regards,
>>
>>Brian

Subject:Re: clipped peaks
Reply by: MacMoney
Date:9/11/2000 7:59:00 AM

ATP
You are right! I use that plugin quite abit for small stuff like
that. Also there are some other plugins that come with Noise
Reduction that help out removing other type of noises like Click and
Crackle Removal, Noise Reduction, Vinyl Restoration along with
Clipped Peak Restoration. I Hope this helps.

George Ware
Mac/Money Studio


ATP wrote:
>>Maybe you could try SF Noise Reduction 2.0. It's a DirectX plug-in
>>that also installs a "Clipped Peak Restoration" plug-in. That might
>>help you. I don't know however, since I've never used that
particular
>>feature.
>>
>>Brian E. Jones wrote:
>>>>I have a recording which peaks are clipped that are not
>>>>above -20db.
>>>>
>>>>What can I do to eliminate this or repair the peaks within
>>>>Forge? I tried the parametric EQ, and tried resampling the
>>>>sound (which reduced the noise generated by the clipping,
>>>>but the sound quality was degraded considerably.
>>>>
>>>>Regards,
>>>>
>>>>Brian

Subject:Re: clipped peaks
Reply by: DJohn
Date:1/9/2001 8:51:00 AM

Here's a post I made to the suggestion box, that might help
you:

I ran into an interesting problem with NoiseReduction 2.0
that you may want to address. I recorded sounds onto a
minidisc and later transferred them digitally to my
computer to edit them with SoundForge. To my surprise, I
had some clipped peaks, so I downloaded the demo of
NoiseReduction 2.0 to see if it solved my problem. To my
surprise the peaks weren't restored.

After sometime I realized the problem was caused by the
interaction of the minidisc lossy compression with your
algorithm to detect clipped peaks. It looks like you detect
a clipped peak by looking for data equal to +32767 or -
32768, but because of the lossy compression, the peaks,
although close to the limit of +32767 and -32768, are not
exactly that. Consequently you don't detect the peak.

If I were you I'd include an option with your clipped peak
algorithm that works for clipped peaks using lossy
compression. Ideally, you'd look at the shape of the peak
for a flat top near the 16 bit limit instead of exactly
the maximum or minimum values. Alternatively, you could
allow an option to explicitly set a "clip limit" slightly
less than the limit of a 16 bit number.

Fortunately, I was able to work around the problem by
increasing the volume 0.6 db, and then apply clip
restoration.

I also tried out Cool Edit's clipped peak reconstruction
feature, which worked correctly on lossy compressed clipped
peaks. Unfortunately, they require you to specify an amount
to scale the sound so the new peaks fit into the 16 bit
number range, rather than automatically scaling it to best
fit the 16 bit number range as you do. So, in the end I
bought your product instead of theirs.

Unfortunately, most minidisc users presented with your
product and CoolEdit would probably conclude yours didn't
work and buy CoolEdit instead.


Brian E. Jones wrote:
>>I have a recording which peaks are clipped that are not
>>above -20db.
>>
>>What can I do to eliminate this or repair the peaks
within
>>Forge? I tried the parametric EQ, and tried resampling
the
>>sound (which reduced the noise generated by the clipping,
>>but the sound quality was degraded considerably.
>>
>>Regards,
>>
>>Brian

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