I have some CDs that when ripped to MP3 and analyzed with MP3Gain show clipping. I allow MP3Gain to process the files and clipping is gone.

My question is this, if clipping is present in the ripped file, does reducing the gain via MP3Gain actually fix the clipping or just mask it by lowering the volume?

Thanks for your time!

When the signal is clipped digitally, the wave above the clipping point is lost. There is no way to recover the data that was meant to be there, but there are techniques to reduce the distortion introduced by the clipping. MP3Gain doesn't apply any of these (it doesn't change the actual data at all).

To answer you question: the clipping is not 'fixed', it is merely made to sound better by lowering the volume.

There is no clipping in the encoded .mp3 file. Clipping occurs when the waveform is reconstructed using the information stored in the mp3 file and the resulting values are out of 16bit range (+/-32767). Lowering the volume using mp3gain (or replaygain when using decoders that use floatingpoint data and don't convert to fixedpoint before the gain change has been applied - like foobar2000) can be seen as multiplying all sample values by a number < 1.0, so the ones that are out of 16bit range before fit in the range afterwards. So mp3gain fixes the clipping by lowering the volume. I'm not sure what you mean with "mask".

If the clipping is already there in the CD, then mp3gain can't fix that.

If the clipping is caused by the mp3 having gain values outside of the range that can decoded properly, then mp3gain will fix it. This sort of "added clipping" can be audible:

http://ff123.net/norm.html

ff123

is there a FAQ of recommended settings for mp3gain? the HA one seems to be really out of date.

you don't need a FAQ for mp3gain

for concept albums with low-volume intermissions: album scan+apply album gain
for single tracks or compilation CDs apply track gain

Thanks for the replies. I come from the telephony world, and when we boost signals to clipping, nothing downstream from that equipment is going to recover the signal.

So, when I rip a CD and see 'Clipping Y' in MP3Gain I worry that the original info was lost in the rip and no amount of level reduction would correct it.

But it seems from these posts that unless the source CD was 'bad' the MP3s will be fine after being processed through MP3Gain.

I thought that mp3gain clipping sign means when you play your mp3s in harware mp3 player device it might happen to distort becouse of the amlifier's supply limitations...
..so is it wrong???

mp3 tracks can clip digitally (and is this the same auible experience than analog distorsion)???

and another question:
where can I find tools to fix mp3 distortion (when mp3gain is not able to help)
(i mean when your mp3 is quiet enough but the peaks are "missing"?


Üdv

So when MP3-Gain says "Clipping" , how do I know, if this is "added clipping" caused by the encoder or clipping that was already on the original cd?
Is there a way to check if a cd has clipping or is there a tool similar to MP3-Gain for WAV-Files?



Greetz, Frankie

If I suspect clipping on the cd I analyze the waveform with EAC. If you zoom in and see peaks where the top is cut flat then there was clipping applied before or during mastering. It's important to zoom in as a noisy track can appear to be constantly hitting +/-32767 but zoomed in you might find that the peaks actually end properly just below the maximum. This type of clipping cannot be fixed. I've seen tools that try to correct it by guessing where the peak should end but there is no guarantee and it will still not be perfectly as it should be.

Clipping comes from 2 different "sources":
1) The CD is already clipped by mastering and there's no way to correct the damaged peaks.
2) The clipping is introduced by MP3 decoder which outreaches the full (digital) scale and the peaks are cut-off (clipped).

No, the artifact is a little bit different, try to search the HA. I know there's somewhere an answer!

As I've written above, you can fix the source of MP3 - Wave file in an Audio Editor, apply ReplayGain Tag (Foobar2000 or MP3Gain Analysis) or apply the actual gain by MP3Gain, so there will be changes in the MP3 stream...

I hope this will help you!

Some useful links:

Wavegain vs. MP3Gain
Clipping!
mp3gain