A Cubase / mp3 question

[antonbanks]

I've got perhaps an ignorant question about mp3s and how Cubase handles them.

If I use a 128k mp3 sound file in Cubase (or any other platform) and save the new file as a 128k mp3, does the software compress the 128k audio again?

In other words, do I end up with a 128k sound file that has been compressed twice? (128k treated as the "original" and copressed again)

I imagine that the software is "smart enough" to know not to compress the file again but just wanted to be sure.

Thanks in advance,
Anton

[RDR]

AFAIK cubase converts mp3's to wav or aiff depending on your project format and then re-encodes it to whatever you set in the export options.

the mp3 format uses fourier methods and comb filters to work out which frequencies are not needed at certain points in the file as they are being masked by other sounds or are too quiet to be heard. Once those sounds are removed they cant be put back. MP3's themselves cannot be editted, hence the conversion.

The big question is which exact method of converting to mp3 did you use before cubase and which method does cubase use. The best mp3 converting is usually acknowledged to be the LAME encoder, but there are probably better other ones, so i suspect the differences between input 128kbs and output 128kbs from cubase is minimal.

you might want to ask on the cubase forums for a more detailled answer.

You could always check by ear as welll, and also 128kbs is shit.

[acidsaturation]

So in lay-man's terms, effectively it does compress it twice, as the unpacked file will still have the artefacts of the compression, however the heard effects of the second compression will be less than the first...

I've used compressed sounds in a track and once the compressed file is mixed in there is less difference as other things will fill the gaps so to speak.

But yes, 128kbs is shite.

[RDR]

So in lay-man's terms, effectively it does compress it twice, as the unpacked file will still have the artefacts of the compression, however the heard effects of the second compression will be less than the first...

I've used compressed sounds in a track and once the compressed file is mixed in there is less difference as other things will fill the gaps so to speak.

But yes, 128kbs is shite.

you can tell im a lecturer cant you.

ramble ramble ramble.

[acidsaturation]

Yep! :wink:

[acidsaturation]

I'm impressed anyway that I worked that out... After spending an hour swapping cables about on my HiFi amp last night convinced I'd blown a channel, then to realise I'd knocked that balance knob had been knocked off centre I was beginning to fink I woz fick.

[RDR]

I'm impressed anyway that I worked that out... After spending an hour swapping cables about on my HiFi amp last night convinced I'd blown a channel, then to realise I'd knocked that balance knob had been knocked off centre I was beginning to fink I woz fick.

quality!

[antonbanks]

Hmmm... wasn't expecting that. In this case that's probably for the best.

The audio in question is from my radio show. It gets recorded off the internet stream at 128k. I sometimes go back and do a little editing and save the file again. Basically, I record it that low so people don't rip tracks from there.

Thanks guys!

PS- So if I've understood you correctly, if I save the audio at a higher bitrate the second time around it shouldn't get compressed much more than it already is. True?

[RDR]

if you save it at a higher bit rate it wont make any difference. You cant go back up to 256kbs quality once the original is saved at 128kbs. it will always sound like a 128kbs file unless you compress it even further to say 96kbs.

is that what you meant?

PS: no worries, we try to help if we can :)

[antonbanks]

Not exactly. I know that I'll never get better than 128k.

I meant that if I save the file to a higher bitrate than 128k the second time around then the file will get compressed less than had I saved to lower than 128k, correct?

Bear with me, I'm trying to make sure I undestand correctly...

[acidsaturation]

The file itself will be less compressed, but some of the information will have been removed during the first compression and not replaced when the file is unpacked.