What is VBR in iTunes import settings?

[chebby]

I am thinking of ripping some 'not quite so critical' stuff to iTunes in 320k AAC (with correction ticked) instead of my normal Lossless settings.

When I went into iTunes preferences to set it to 'custom' and 320k I was presented with a tickbox for 'VBR' (variable bit rate).

Is it likely to affect quality? Will I not actually be getting 320k with VBR ticked?

Thanks

 

[Andrew Everard]

Yes, you'll get the maximum bit-rate - it's just that VBR will reduce the bit-rate if the signal being ripped is less complex, then up it again when things get busy. In very rough terms, of course...

 

[John Duncan]

I think it basically uses lower bitrates when the music is less complex, thus saving space - eg silence is recorded at 128. Have never tried it though.

 

[chebby]

Thanks for the quick replies chaps.

So VBR is not necessarily another drop in quality then?

I have some CDs of old (1930s, 1940s) big-band/jazz stuff like Benny Goodman, Glenn Miller, Hot Club de France etc etc.

Being such old recordings they don't really benefit from being lossless but I don't want this VBR setting to take them below an acceptable level of quality.

 

[John Duncan]

Yeah basically I think you get 320 when you need it, less when you don't.....

 

[Xanderzdad]

Based on my experiments over the last year or so, VBR will not just reduce the bit rate, it also increases it in complex sections. The average bit rate for me, when using 256 VBR is often 280-290kbps. It also sounds better than straight 256.

It is an excellent compromise.

BTW VBR is not available at 320kbps, only up to 256kbps using the AAC encoder in iTunes.

 

[chebby]

OK iTunes has just made my query null and void.

I set it to 320k and ticked VBR and it immediately informed me that VBR cannot work with 320k !!

Sorry. Did not mean to time-waste.

(Why doesn't the blooming tick box disappear when 320k is selected? Pah! Rubbish software.)

[Edit] Thanks Xanderzdad. Was typing when you posted.

 

[chebby]

Well I set it on 320K and did a test track.

I chose an Elvis track ('Don't be cruel') as it was the first CD out of the first box.

I ripped it at 320K and switched between the Lossless and 320k versions.

I did not think the difference would be that big! The 320K version sounds thinner with less body to the bass and the 'acoustic' or space was reduced. It sounded like a big radio.

Not good.

Also the size only went down from 6.6MB to 4.7MB (for a 2.05 minute track)

So pretty pointless exercise really.

I am not going to bother with 320k in future. Too noticeable a drop in quality for very little gain in space.

 

[fatboyslimfast]

That's weird Chebby - I found the same thing when listening via my Classic, but it's not as noticeable through the AE/Beresford (maybe the Beresford has a "way" with lower bitrates...?)

 

[Peter Larsen]

I have tried using VBR in iTunes at 256kb (max at VBR), and I'm not impressed. Especially when listened to through headphones, the sound level is not consistent when compared to the original CD (it often fades and then comes up again when going from simple to complex passages in music) and a lot of the more complex tracks sound slightly distorted. I know that iTunes got an update recently where it supposedly addressed a quiality issue with encoding on some Macs. I haven't done any ripping since that update, so I don't know if thats what caused the bad quality on my MacBook Pro or if it has been fixed.

 

[professorhat]

chebby:Also the size only went down from 6.6MB to 4.7MB (for a 2.05 minute track)

That's a very small lossless track - mine are around the 20 - 40Mb size for a 3 - 4 minute track.

 

[chebby]

professorhat:
chebby:Also the size only went down from 6.6MB to 4.7MB (for a 2.05 minute track)

That's a very small lossless track - mine are around the 20 - 40Mb size for a 3 - 4 minute track.

They vary of course. A two minute, 1950s, Elvis recording (mostly acoustic) is not that complex.

The bit rate (lossless) on that particular track is 473kbps. Most of my lossless material is up around the 800 - 1000kbps mark. (Sometimes higher)

 

[professorhat]

Understood. In which case, agreed - for the sake of 2 - 3 MBs, it's not really worth it.

 

[chebby]

OK I have just found a good use for VBR and 256K AAC.

Just took delivery of my own complete set of BBC Eyewitness (A history of the 20th Century in sound) CD boxes.

There are 10 boxes - one for each decade - and all but one box contains 4 CDs (39 discs in total)

If I had used lossless these would have all taken out a fair old chunk of my HD. (I estimate about 15 - 16 GB)

So I switched the import settings to AAC 256k with VBR and 'Optimised for Speech'. (Correction on of course.) The quality is fine (actually very good) as it is all spoken word.

So far (11 discs loaded) I have not dented the HD space noticeably (the HD was 15 percent used before I started and is still 15 percent used). I think the whole 39 disc set may end up taking 1 percent which is OK. (Lossless would have taken up to 5 or 6 percent.)

My experiments earlier in the week with 320k AAC proved that going below 'Lossless' quality for music was unsatisfactory, even with low complexity music. But with speech it is fine at 256k AAC VBR.