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[Health Nut]

Hi,

Opinions on the highest quality lossy mode appreciated.  Also, how much space do you save when using VBR, and how much of a quality hit do you take when using VBR instead of CBR.  I would imagine that CBR should give overall higher quality since it uses max bitrate of 320 all the time (but takes more space).  Any opinion on MP3 320 vs AAC 320?  Also, why can't I enable VBR with 320 AAC?  I'll probably use lossless, but I'm curious to know what the highest quality lossy mode is....

[pank2002]

This is really questions for Hydrogen Audio. They'd go nuts and start a rant of 10 pages (AT LEAST!)

Anyway, I like lame --alt-preset standard because 1) it's portable (it will work on any machine and any mp3-player) and 2) I mostly can't tell the difference. Least of all on the move!

On high bit rates lame mp3s beats aac.

I wouldn't say you save space using vbr. You just get a higher quality. Fx a --aps file will usually be between ~160-260 or so. Depends on the track in question. Rather than having all the bits in the same bit rate you get the bits which will sound best in full quality in full quality whereas the bits which can be played back in a lossier quality gets a lossier quality. So a CBR 160kbps is the same as a VBR 160kbps.

Unless you have really, really ridicules good headphone you won't gain anything by using lossless. That's my experience at least.

Cheers,
Rasmus

[Alex B]

CBR 320 kbps MP3 keeps the bitrate constant. VBR tries to keep the quality constant. It can go up to the 320 kbps bitrate when needed, but most of the time the same quality doesn't need that much bitrate. VBR Extreme is the best VBR MP3 quality in MC and also in general. The general consensus is that the LAME encoder is the best MP3 encoder, especially at high bitrates. MC uses LAME. The MP3 encoder in iTunes is not usually found to be as high quality. Apple has given priority to its own AAC format.

I would say that LAME CBR 320 kbps and iTunes AAC 320 kbps are on par. LAME VBR extreme is as good most of the time (99,9% or so).

Sometimes VBR encoding can make wrong choices on difficult passages. I read this thread at Hydrogen Audio forums: http://www.hydrogenaudio.org/forums/index.php?showtopic=37003. After quickly testing the sample file and hearing the obvious encoding error I decided to encode the sample with several lossy encoders using a few different settings and bitrates. I used LAME 3.90.3 (CBR and VBR), LAME 3.97 beta 1 (CBR and VBR), Vorbis aoTuv beta 4 (always VBR), Musepack 1.15v alpha (always VBR) and iTunes 5 (CBR and VBR).

Here are my 27 test files in a zip package (6.9 MB): herding_calls_sample.zip. The original lossless file is available at HA.

If you have a high quality sound system you could try to find differences. With lesser systems it might be impossible to distinguish them. Each sample is 11 s long, so it is easy to make a playlist of them and let MC play through the list. You could select random play and close your eyes. Keep in mind that this is only a rare extreme sample. Most of the time finding differences is more difficult.

By the way, Apple added AAC VBR to iTunes 5. However it is not a real VBR. It works like LAME ABR (average bitrate). iTunes AAC VBR doesn't change the average bitrate according to the complexity of the encoded tracks.