Stopping overs with MP3

jamescater · 20th June 2008

I've noticed that mp3's created from WAVs that have been mastered to 0db produce overs when analysed in Wavelab

In this age where everyone rips their own MP3 from CD's onto their iPods should we produce masters that peak at -0.2db to stop this issue ?

Or do we just get max level out of the CD and not care about the home ripper ?

mworks · 20th June 2008

It's always smart to set your max level to -.2 or even -.5 for a few reasons - it allows for processing downstream such as lossy compression encoding that might create the overshoot you are seeing. It also means that a sh*tty consumer DAC that's designed with zero headroom in the analog stage won't sound quite so bad when playing your record.

Alexey Lukin · 20th June 2008

When compressing with low bit-rates, even -0.5 dB may be insufficient to prevent overs. I wish that players would have built-in limiters (or replay gain feature) to turn clipping into smooth limiting.
iZotope RX has a 32-bit float decoding mode to preserve mp3 overshoots from being clipped (QuickTime required).

Andy Krehm · 20th June 2008

Quote:

Originally Posted by Alexey Lukin

When compressing with low bit-rates, even -0.5 dB may be insufficient to prevent overs. I wish that players would have built-in limiters (or replay gain feature) to turn clipping into smooth limiting.
iZotope RX has a 32-bit float decoding mode to preserve mp3 overshoots from being clipped (QuickTime required).

Do you mean when making mp3's from iZotope RX? I don't know if I am understanding you correctly but would welcome any .wav to mp3 conversion program that would not clip audio during conversion.

Alexey Lukin · 20th June 2008

Oh, no. I just meant decoding of mp3 to wav. I don't know any programs allowing to escape clipping during mp3 encoding; the safest way is to keep some headroom margin when creating a master for mp3.

3rd&4thT · 21st June 2008

I've discovered recording spoken word, mp3 overs can depend on frequency as well as level. If you're going for low bitrate/small file size and can get away with it, things are much cleaner rolling off some below 150Hz. Be careful above 12K, and your splat rate will go down. And the impression of loudness will go up, even if it's mostly midrange.

Barbarous, but there you are. mp3 sucks. Always did. Always will. I hate it.

3rd&4thT

siddhu · 21st June 2008

I remember that there was a PDF floating around that showed how lossy compression raised the Db of program material.

Everything from low bit rate MP3s to Dolby and DTS.

I've looked for it far and wide and have been unable to find it.

Does anybody remenber where it can be found....I've Googled for it to no avail!!

20th June 2008	#1
jamescater Gear nut Joined: Sep 2007 Location: London Posts: 92 Thread Starter	Stopping overs with MP3 I've noticed that mp3's created from WAVs that have been mastered to 0db produce overs when analysed in Wavelab In this age where everyone rips their own MP3 from CD's onto their iPods should we produce masters that peak at -0.2db to stop this issue ? Or do we just get max level out of the CD and not care about the home ripper ?

20th June 2008	#2
mworks Gear maniac Joined: Oct 2006 Location: People's Republic of Cambridge Posts: 211	It's always smart to set your max level to -.2 or even -.5 for a few reasons - it allows for processing downstream such as lossy compression encoding that might create the overshoot you are seeing. It also means that a sh*tty consumer DAC that's designed with zero headroom in the analog stage won't sound quite so bad when playing your record. __________________ m-works.com hear here

21st June 2008	#6
3rd&4thT Lives for gear Joined: Oct 2007 Posts: 761	I've discovered recording spoken word, mp3 overs can depend on frequency as well as level. If you're going for low bitrate/small file size and can get away with it, things are much cleaner rolling off some below 150Hz. Be careful above 12K, and your splat rate will go down. And the impression of loudness will go up, even if it's mostly midrange. Barbarous, but there you are. mp3 sucks. Always did. Always will. I hate it. 3rd&4thT __________________ "Batteries Not Included." "Safe When Taken As Directed." "Available at All Fine Stores." "Check Our Website." "Ask Your Doctor." "Now on DVD." "Member FDIC." "Except in Nebraska." ---------------- Voiceover Tag Team

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20th June 2008	#3
Alexey Lukin Lives for gear Joined: Dec 2007 Posts: 640 Verified Member	When compressing with low bit-rates, even -0.5 dB may be insufficient to prevent overs. I wish that players would have built-in limiters (or replay gain feature) to turn clipping into smooth limiting. iZotope RX has a 32-bit float decoding mode to preserve mp3 overshoots from being clipped (QuickTime required).

21st June 2008	#7
siddhu Lives for gear Joined: Nov 2006 Location: Paris Posts: 623	I remember that there was a PDF floating around that showed how lossy compression raised the Db of program material. Everything from low bit rate MP3s to Dolby and DTS. I've looked for it far and wide and have been unable to find it. Does anybody remenber where it can be found....I've Googled for it to no avail!!