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Author Topic: MP3, VBR, CBR explained...  (Read 1148 times)

BadDog

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MP3, VBR, CBR explained...
« on: December 05, 2003, 04:04:07 pm »

No, I cannot explain it!  I have a 45 GB library that is mostly 192 and 160 MP3 files.  I am looking at buying a portable jukebox player such as the Creative Labs ZEN and thought I would try to fit a little more onto it.  Will there be a decrease in sound quality going from 192 or 160 to VBR High or VBR Normal/High?  What else do I need to know that I did not ask?

The files will be played back in a boat that has fairly high end auto audio equipment.  Once they are converted if there was a sound quality issue in the conversion back to original will the original quality return?  Is there a comparison between 192 to VBR High and 160 or 128 or Normal/High
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rocketsauce

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Re:MP3, VBR, CBR explained...
« Reply #1 on: December 05, 2003, 04:17:50 pm »

It's best to leave your files as they are or re-rip them from the cd, if possible. Converting from 160 and 192 kbps to VBR will pretty much guarantee a loss in sound quality and actually probably wouldn't save you that much space in the long run. And no, the original quality will not return if you convert your CBR files to VBR and then back to CBR. In fact they will sound even worse than the first CBR to VBR conversion. Think of it in terms of making a copy of a copy of a copy, etc. Each successive copy is worse than the one before it.

Rob
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xen-uno

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Re:MP3, VBR, CBR explained...
« Reply #2 on: December 05, 2003, 04:31:55 pm »

From an earlier experiment I did...

MJ setting / ~ LAME equiv
VBR Normal to Normal/High / --alt -preset standard aka -aps
VBR High / --alt -preset extreme aka -ape

Most of my files are -q 8 ogg's...but of 180 files I have aps'd (LAME 3.92), the average bit rate is 175 to 180 (low: 123 | high: 211). You should stick with the presets for they have been tested and will give you the best sound quality possible with the mp3 format. Conversion?..from an mp3 to wav and then back again? Probably not...if the original mp3 is an -aps or -ape, then you might not notice sound defects...unless you did a direct comparison (ie ABX).

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modelmaker

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Re:MP3, VBR, CBR explained...
« Reply #3 on: December 05, 2003, 07:04:59 pm »

You certainly are not going to regain enough space to make the time and effort worthwhile. VBR High files generally average 170 - 220 bps (with lows of 60 & highs of 300), so storage-wise not much different than the pretty good (for lossy)160 & 190 bps you already have.

You would have to re-rip everything to get the small increase in sound quality which I'm not sure you are going to be able to hear on a boat anyway no matter how good the stereo is. You're going to have some ambient(background) noise ie surf/waves/wind/engine/wine/conversation/more wine.
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Jay.

"Life is what happens when you're making other plans"     John Lennon.
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