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LAME + Dibrom's presets/switches + remarks
xmixahlx
post Jan 5 2002, 05:19
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ok...i have read and read and read trying to learn the technical details of the "--alt-presets" but i still have some questions:

1. what are the current switches in each of the presets [i.e. extreme, standard, and their "fast" counterparts].

2. could someone explain what the non-obvious switches do for those that aren't involved in programming/developing LAME

i think it would be a good idea, and probably save some newbie questions [not unlike this post, *tears*] to sticky all the information conceivably possible in regards to the "--alt-presets" and why these switches are used. i don't desire "the history of the presets" just what they do in the current/recommended compile. also, differences in the "fast" and "non-fast" presets [i.e fast standard vs standard] would be GREATLY appreciated [why? because, well...they seem pretty much the same to me audibly]

3. and could somebody explain to me the reason for writing or not writing the Xing Header?

4. what is a good program for analysing mp3's [i.e. to see the differences between encoding switches and the quality they produce within the same sample] that is exhaustive...

5. can anyone REALLY hear a difference between a CD track and their LAME "alt preset standard/extreme" counterpart?


ok...now for some remarks


1. this forum is awesome, i am learning just a phenomenal amount of information in minutes/hours/etc. thanks for this resource and don't let the "powers that be" get you down...[i.e. the official developers of LAME]

2. if LAME is open-source, and their are quite alot of people creating compiles, why is there still an "official" version...why not just release versions like "3.90dm1.1" and "3.90mitiok1.1" etc...this would clear up alot of confusion/egos/etc. and allow those that use certain aspects of LAME [i.e. dibrom's presets in dibrom's compiles] for those that desire them without all this feminine, drama...[damn flaccid ninnies]

3. to dibrom [and other devs w/ PM]: don't let this opposition worry you. anyone who is even *slightly* knowledgeable in regards to encoding/LAME/mp3 would use this site as their primary resource for EVERYTHING [compiles/information/forum]...i am sure that the opposition derives from lowly emotions, "if you know what i mean"

4. in no way shape or form do i think that releasing 3.90.2 was in bad taste, disrespectful, unbecoming, etc. and all who think so have some sort of issues...as far as i am concerned compiles from this forum ARE the official versions and i use and inform others only of this site.

5. man, 700+ posts in a couple months...geesh Dibrom...why do i have such a comfortable feeling that this post will be responded to quickly...thanx, again...

i don't really expect a complete response to all of this...it was more to just post my questions/comments. but responses to the questions would be greatly appreciated


and just a side note, it sucks having to "un-learn" everything from r3mix.net...man does that guy has issues...he seems like some sort of deluded fool after coming to this site, oh well...


issues, issues, issues, issues, and more issues...geesh

[btw...i have been reading these forums for about a month now, but this is my first post and i just registered not too long ago...i hope my questions seem more than retarded...just slightly more...]


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Dibrom
post Jan 9 2002, 08:30
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QUOTE
Originally posted by xmixahlx
thank you JohnV for responding to my post, and thanx for your comments...

from JohnV: Define non-obvious..
 
well, if i knew the commandline i could explain what i mean better...but switches like bitrate and quality and vbr modes i understand, but things like npsytune? what is that? and why use a lowpass when you can just encode the whole file? doesn't that produce an inexact "replica"?


To start off, FAQs are in the planning, they just haven't been implemented due to a lack of time yet. I'm hoping that can change soon.

As for non-obvious switches, I'd request that you ask on a switch by switch basis to make it easier to respond. In regards to the ones you mentioned:

--nspsytune uses a different psymodel than the one defaulted by LAME. In fact, it is the same psymodel but modified and improved. It usually performs better in the area of joint stereo handling, noise measuring, pre-echo, dropout prevention, etc. I use --nspsytune and then build upon it with my own modifications, further improving it, to provide a better overall psymodel than what LAME normally uses.

A lowpass is used to save bits. MP3 will never provide an "exact replica" so in regards to that, the issue is moot to start with. A more ideal solution however would be to use an adaptive lowpass (using different frequency cutoffs per frame). Maybe this will be implemented in LAME at some point, but I don't know.

QUOTE
from JohnV: ...(fast uses vbr-mtrh, non-fast uses vbr-old)

i understood this to be the main difference between the two modes, but on my comp [with both standard and extreme] "non-fast" does ~2x-2.5x but "fast" does ~3.5x-4x so i guess my question was..."why use non-fast when fast is 75% faster?" and "is the only significant difference between the two modes the vbr setting used?"


Because vbr-old is still on average, higher quality than vbr-mtrh. This assertion is based on extensive testing of difficult clips with and without my custom modifications implemented.

It is true that the quality difference is usually small to unnoticeable but given the fact that I'm already trying to tune quality down to such a precise level, it doesn't make sense to forsake a higher quality option. At the same time, I realize that this last little extra bit of quality may be irrelevant to some and that they would prefer speed instead... thus you have a choice smile.gif

QUOTE
NOTE: with sgt pepper's track 13 [dog whistle] doe s this sample indicate that the vbr-mtrh is a more accurate than the standard mode vbr-old?


Apparently so. This is not directly related to the vbr modes themselves though (I think), but instead to another code level difference between --alt-preset standard and fast standard.

At any rate, the difference seen here is, in my experience, not indicative of common behavior. Obviously there will be a case or two where fast standard is better, but it's the average that is more important here, and it is the average that the normal standard mode has, again in my experience, performed slightly better.

QUOTE
and also...are there any settings that are widely used in addition to the "--alt-preset" switches? [e.g. "--alt-preset fast standard -X...etc."]


Nope, and there shouldn't be. Many of the experimental switches do not perform in the same manner with the --alt-preset switches as they do without. Furthermore, the --alt-preset switches are constantly updated to prevent this sort of situation from becoming a necessity.
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