[vorbis] What quality should I use?

[John Morton]

On Wed, 08 Jan 2003 16:00, Corey Miller wrote:
> I am considering archiving my entire music collection using Ogg.  I do
> not have any set limit on space, but my movies are going to be held on
> the same hard drive as soon as tarkin is final ;) so I don't want them
> to take up too much space.  I'm by no means an audiophile, but I can
> tell the difference between a q3 and q4 ogg easily.  Is there any q
> level that would give me the best quality for not taking up too much
> space?  How much does q10 usually use?

q10 is pretty massive for lossy, and there hasn't been quite as much 
attention to tuning going on up in the ridiculously high quality levels, 
so the difference between q9 and q10 is probably not that significant, even 
if you had the ears and the gear to discern. 

I suggest you grab some passages from songs you're very familar with, and a 
sample of the common 'hard to encode' passages [1] Encode them at, say, 
quality 4, 4.5, 5, 5.5 and 6 and see if you can spot any differences that you 
can ABX[2]. I'd recommend using a good pair of headphones for this.

I then add about .5 to the quality level where I can no longer pick a 
difference as insurance against either better gear or training revealing 
artifacts down the line, or running into an album that contains hard to 
encode passages. Given that the amount of time you'd need to spend working to 
buy double your current storage space in a years time is going to be 
massively less that re-encoding a large collection of albums, it's well worth 
the fairly miniscule size hit.

You might want to consider using two different quality levels, too. I tend to 
use q7 for live stuff as I find q4.99 produces noisy, scratchy applause on a 
lot of live tracks. 

HTH,
John

[1] Google for hihat, fatboy etc to find pages full of them.
[2] Monty wrote a wee perl script to automate this; anyone have the link?
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