I've converted a wav file to .mp3 by LAME 3.98.4 (64-bit),
using the command "lame.exe input.wav --preset insane".
Then, I checked the details of the mp3 file by MediaInfo.
It showed the encoding settings are "-m j -V 4 -q 3 -lowpass 20.5"
It's quite weird, as there is a "-V 4" switch even when the file is encoded in CBR 320k.
And I've heard that "--preset insane" gives the best quality possible in LAME,
but why it uses "-q 3" instead of "-q 2"?
Isn't "-q 2" supposed to be better?
Is the information provided by MediaInfo accurate?
Probably “-V 4” was a guess. Either way, it’s not true and nothing to worry about.
-q values from 0–3 are equivalent in the default VBR mode (as are 4–6 and 7–9, if I remember correctly).
For my -V 2 encoded MP3's MediaInfo correctly reports "-m j -V 2 -q 3 -lowpass 18.6 --vbr-new -b 32", can you check your file(s) with the brilliant Mr QuestionMan (http://www.burrrn.net/?page_id=5)?
Presets are fine tuned by devs also based on and audiophiles/experts input and therefore I wouldn't override the -q setting manually, anyway from the official LAME docs:
=======================================================================
algorithm quality selection
=======================================================================
-q n
Bitrate is of course the main influence on quality. The higher the
bitrate, the higher the quality. But for a given bitrate,
we have a choice of algorithms to determine the best
scalefactors and huffman encoding (noise shaping).
-q 0: use slowest & best possible version of all algorithms.
-q 2: recommended. Same as -h. -q 0 and -q 1 are slow and may not produce
significantly higher quality.
-q 5: default value. Good speed, reasonable quality
-q 7: same as -f. Very fast, ok quality. (psycho acoustics are
used for pre-echo & M/S, but no noise shaping is done.
-q 9: disables almost all algorithms including psy-model. poor quality.
from the official LAME docs
…which are very outdated—even more so than I already thought! These quotes are from last year (click either small arrow to view the discussion):
LAME uses -q 3 by default at least since 3.94beta (december 15 2003).
Right. I've got that now. Which means that parts of the documentation are almost seven years out of date.
Thanks for all your help.
I've checked my file by Mr QuestionMan.
It correctly identified the setting as "MPEG 1 Layer III LAME 3.98r [alt-]preset insane (?)".
I think I would just stick to "--preset insane" and ignore those details shown in MediaInfo, which might be inaccurate.
I think I would just stick to "--preset insane" and ignore those details shown in MediaInfo, which might be inaccurate.
Is there a specific reason you want to use that preset? Some ABX testing may reveal that you don't need that, and could use one of the VBR modes and never notice the distance (apart from saving space.)
The wiki here has good info on LAME presets:
http://wiki.hydrogenaudio.org/index.php?ti...lt-preset.22.3F (http://wiki.hydrogenaudio.org/index.php?title=LAME#Hey.21_What_happened_to_.22--alt-preset.22.3F)
To summarise, presets used to activate specific tunings not used by normal encoding methods, but these were later incorporated into the main code and thus presets are now equivalent to basic settings; in this case, simply -b320.