[vorbis] quality settings

[Greg Wooledge]

Erik Fuller (Phaedras at gmx.net) wrote:

> ARGH! I am at a complete loss as to which OGG quality settings to use: 8?
> 10? 3?

Take a look at
<http://www.lammah.com/~xercist/vorbis/qual_vs_bitrate.png>.

There's a sudden jump (discontinuity) in the bitrate/quality graph at
-q 5 because that's when Vorbis uses lossess channel coupling (a big
hit in size).

> With LAME, I at
> least used to know 192 kbps with -q0 was a perfect size/quality proportion.

... for you. ;-)

For me that would be overkill, since I can't tell the difference even
with lame --abr 160 -q0 --nspsytune.

For you, I'd say listen to oggenc -q 4 and see if you can find any
difference at all.  If not, then -q 4 should be good enough.  If you
can hear differences, then keep increasing the number until you can't.
A few people on the hydrogenaudio forum seem to think that -q 4.99999
is optimal (because it slides in underneath the -q 5 bitrate spike).

Personally I'm using -q 3.5.  -q 3 is transparent for me and I figure an
extra .5 may be a safeguard against a track that's a bit more challenging
for the encoder than what I've ABX-tested so far.)


-- 
Greg Wooledge                  |   "Truth belongs to everybody."
greg at wooledge.org              |    - The Red Hot Chili Peppers
http://wooledge.org/~greg/     |


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