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a response to a growing rumor...
Dibrom
post Feb 14 2002, 00:03
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Pio2001,

It's a shame you didn't post your response to my graphs on this board here, but since I'm not registered at r3mix.net I'll just respond to it here.

Originally written by Pio2001
QUOTE
The pictures shown by Dibrom are interesting, but their interpretation is not easy.


Really? It seems as if they're not so easy to interpret in the context I discussed them in, only if you wish to interpret them that way (being difficult). The evidence is clear enough I think... how can you attempt to spin that?

QUOTE
[b]I'm not sure that APS shows more HF content than r3mix, because it rather shows a large band and large time of very low HF level, while r3mix shows short burst of high level HF (especially on the them sample).


Umm... so? Low level HF or not, it's irrelevant. The fact of the matter is that it is HF, and it is audible in some of these cases. Saying that you "aren't sure" is a bit rediculous. In all but the "them" sample, it's a very clear cut case. In "them" the sum of the high frequencies across the file are encoded more often in --aps than in --r3mix. There's more stability and accuracy in terms of quality in the --aps file.

QUOTE
To know wether R3mix or APS shows more HF content, a global spectrum analysis of the sample should be made, instead of a sonogram.


--r3mix may at times show higher peaks in the one sample, but remember that this is by .5khz at 19khz, which is, again, not going to be significant in any case compared to the artifacting shown in the --r3mix sample.

QUOTE
But I don't think that the RMS level of HF content means anything. Remember that those are nearly unaudible frequencies, therefore only yellow plots should be taken into account. Grey parts are surely completely inaudible. From this point of view, r3mix shows more HF content than APS in the "them" sample, and the other sample show no (audible) HF content at all.


Sorry, but I beg to differ. Having spent a large amount of time tuning LAME and at times using sonograms to determine the point of error, I can say with confidence that these frequencies you deem to be inaudible, are actually quite audible in some cases.

Have you ever heard of the artifact termed noise pumping? This is caused by a failure to encode enough (high frequency) background noise, usually in a quiet file. This is the type artifact you will get if you do not encode this to a high enough frequency, and from personal experience and that of many people on this board, --r3mix does not. This is at least partially due to the ATH in --r3mix being too high (which also leads to other artifacts such as ringing which is actually very rapid and short bursts of the "noise pumping" or "dropout" type problem).

Other than that, I find it a bit ludicrous that you would say that the --r3mix sample shows more high frequency content and that the problems would be inaudible. Fatboy, spahm, and many others show the exact same problems and as with them, they are certainly audible. Yes, this is on impulse samples, but the same effect induces different artifacts in other cases.

The point then remains, that --alt-preset standard encodes more high frequency content, and with higher accuracy, than --r3mix, especially on difficult samples.

QUOTE
But remember, graphs mean almost nothing. EG the HF part could in fact be some impulse content. In that case, the lack of HF content doesn't "muffle" the sound at all, but creates pre-echo instead.


True, but I never said anything about "muffling" at all, I only ever discussed high frequency content by itself. So then, just change the statement. "--r3mix shows high frequency pre/post-echo in addition to many other artifacts due to its failure to properly encode high frequency content in many cases".
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user
post Feb 14 2002, 00:45
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Hi,

in r3mix and here people are referring to some graphs.

Are they published ?

If, where ?


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JohnV
post Feb 14 2002, 01:05
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Uhm, user.smile.gif About 7 messages above your post.
Here: http://www.hydrogenaudio.org/forums/showth...d=8878#post8878


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JohnV
post Feb 14 2002, 02:38
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I'd say you really can't tell absolutely which one of the presets is objectively better at high freqs.
Just by looking at different spectrals, it seems that APS is almost always better with consistency of somewhat below 16kHz (less dropouts,ringing), and some of the test samples seem to verify this (bloodline,serioustrouble etc.)
But sometimes APS seems to have a bit more isolated frequency spikes above 16kHz which could mean ringing, if audible. Then again sometimes r3mix looks less defined above 16kHz..

I'd say it depends pretty much on the case. But to me there's not very noticeable audible difference in very high frequency production. There are very noticeable differencies in other quality areas though, in favor of APS of course.

I would be interested if anybody is able to hear more ringing type of artifact (above 16Khz) with APS using 1400.wav.
http://sivut.koti.soon.fi/julaak/1400.flac


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Pio2001
post Feb 14 2002, 13:09
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QUOTE
Originally posted by Dibrom
Pio2001,
It's a shame you didn't post your response to my graphs on this board here,

You're right, sorry

To make it short, I don't like to discuss sound quality analyzing graphs, Listening tests are way better in my opinion.

I must say that, exept for test samples, I don't hear the difference between r3mix, APS and the original on music chosen at random among well recorded CDs.

The rest is a matter of words, I think.
I of course agree that APS is proven superior to r3mix, but I wouldn't draw any conclusion by myself based on graphs only, without having encoded and listened to the samples themselves.
I still remember your old blind test sample with all frequencies encoded up to 22000 Hz biggrin.gif

PS : seriously, DJ actually remove the counterweight when they mix on a vehicle that is driving, like in a train or in parades.
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JohnV
post Feb 14 2002, 18:00
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QUOTE
Originally posted by Pio2001
To make it short, I don't like to discuss sound quality analyzing graphs, Listening tests are way better in my opinion.
Ooooh, really??!! How surprising. How can somebody actually prefer listening tests, unbelievable, never heard anything like that before, certainly not people here at least....biggrin.gif


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tangent
post Feb 14 2002, 18:34
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QUOTE
Originally posted by Pio2001

To make it short, I don't like to discuss sound quality analyzing graphs, Listening tests are way better in my opinion.

It is true that listening tests are better to discuss quality, but graphs are not completely useless. You have to realise that Dibrom was not using the graphs to discuss quality, but to discuss BEHAVIOUR of the encoder. Now graphs are the perfect tools for this purpose. The right tools for the job, remember? Many people looked down on EAQUAL as a decider of quality, but I think it's silly. Although you can't use EAQUAL to replace listening tests, EAQUAL is useful for many other purposes too (e.g. those Ogg bitrate vs quality graphs).

In the case above, you have to realise that Dibrom did not use the graphs to say that one setting is better than the other. He used the graph to support his findings that one setting encodes more HF content than the other. This is plain fact, and the conclusion he draws is correct. Did he say that one sounds better than another because of the conclusion? No. But he proved a valid point, and that's the important part.

Anyway, the conclusion is just because --r3mix lowpasses higher doesn't mean it will encode more HF content than --alt-preset standard. It is not hard to figure out why: In most cases, HF frequency content falls below the ATH curve (which is already very high in the HF region) and don't get encoded at all. In this case, the ATH curve combined with the noise measuring algorithm of --alt-preset standard decides that more HF content needs to be encoded than --r3mix's algorithm.

The second thing is that graphs seems to indicate that ringing is occuring in the --r3mix samples. Although we cannot be sure we can hear it without the listening tests, we can recognize the ringing syndromes from the graphs. You may want to visit http://ff123.net/ringing_graph.html to understand it better. In this case the graphs are useful in showing that the --r3mix encode shows the syndrome and signs of ringing. But we cannot conclude that this is audible in the sample itself without a listening test.

Therefore: Don't underestimate the usefulness of graphs. It cannot replace listening tests, and probably is not as useful as listening tests. But it is a very useful tool when used properly. Unfortunately, it has been given a very bad reputation because graphs have often been abused in the past.
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Gecko
post Feb 14 2002, 19:52
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Apart from discussing the point of the high cutoff why not just change it if you think you must? It may do more harm to the mid and lower range so I can't recommend it, but that's not the problem here.

--alt-preset standard --lowpass 19.5

There. Tested on "RMB - Love is an Ocean" which raised the respective bitrates from 212 to 216 (values from Winamp. Encspot says 213/217). This song has a very high amount of high frequencies which go up to 22kHz. A quick listen revealed no obvious difference or flaws (but that's only me listening). Spectral view also showed that more hf were encoded (no visible drop-outs; also, I didn't bother to look at r3mix).

So if you persist on having a higher lowpass just use it for all I care and still have the benefits aps offers over r3mix! Noone forces you to stick to one particular lowpass. But be aware that it may have some negative side affects.
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Dibrom
post Feb 14 2002, 21:01
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QUOTE
Originally posted by Pio2001
To make it short, I don't like to discuss sound quality analyzing graphs, Listening tests are way better in my opinion.


I wholeheartedly agree with this, and it's the very reason that I've never used graphs to judge quality in such a manner. If you look at every method I've used along the way to improve the dm-presets, and then the --alt-presets, it's [b]always
been based on listening tests. I of course understand that cannot gauge relative quality. But that wasn't my point here either. tangent pretty much covered it I think... but basically it was just to state a fact, and that was the point about the lowpass 19.5 vs 19 being mostly irrelevant and misleading, and that it would be more appropriate to use --aps if one was concerned with high frequencies in any case.

QUOTE
[b]I must say that, exept for test samples, I don't hear the difference between r3mix, APS and the original on music chosen at random among well recorded CDs.


Of course you won't always hear a difference.. but it certainly is there. It has been noted by myself and others on a very wide range of music. I'd say that perhaps the areas where --r3mix fails very regularly though is in quieter music (ath is too high as you see) and electronic music (many other reasons).

QUOTE
[b]I of course agree that APS is proven superior to r3mix, but I wouldn't draw any conclusion by myself based on graphs only, without having encoded and listened to the samples themselves.


Sure. But I've already drawn all my conclusions from all of the vast amount of listening tests I've done and many other people have done in verification. At this point I already know (and so do most people) what I stated, I didn't need to draw conclusions from it biggrin.gif

QUOTE
[b]I still remember your old blind test sample with all frequencies encoded up to 22000 Hz biggrin.gif


smile.gif
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fewtch
post Feb 15 2002, 08:43
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QUOTE
Originally posted by tangent
Really? Most of the time what they say is "My setting is better! Use '-v0 -q0 -ms -k --lowpass 22.05'. With this setting the sound is no longer muffled, stereo image is conserved, and it doesn't sound so bad with those artificial sine sweeps I create using CoolEdit/SoundForge"

I plead guilty to making such a statement before smile.gif ... but i am also a recent convert to the --alt-presets. After doing some research (and listening tests) it was enough to convince me.

If it were possible to do, I would like to see a way to raise/lower the default lowpass, without affecting other frequencies too much (e.g. code level tweaks that would raise/lower the bitrate or tweak other parameters to compensate) -- maybe that would quiet some critics, and it could be useful in other respects.


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cd-rw.org
post Feb 15 2002, 10:28
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Just by showing up again Roel has already done more for the audiophile MP3 community than some of the posters in this thread. He re-initiated the discussion about optimal LAME settings and that's always a good thing.

The imaginary "JS-collapsing" pops up every now and then. It think it's still mostly due to the misunderstanding JS and the fact that mp3 scene people tend to promote stereo encoding. Usually the complaining users disappear when someone asks for a ABX.

To the APS lowpassing - it naturally is a trade-off. Lowpass is always "lose some win some"-situation. But so far it has been a very succesful trade-off, since APS has performed so well in peoples' testings, and I think it is the wrong end to start tweaking from - there's not much to fix there...


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Dibrom
post Feb 15 2002, 11:29
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QUOTE
Originally posted by cd-rw.org
Just by showing up again Roel has already done more for the audiophile MP3 community than some of the posters in this thread. He re-initiated the discussion about optimal LAME settings and that's always a good thing.


There's only one problem. The discussion he "re-initiated" appears now to be nothing more than to debate the points of the --alt-presets (or why they aren't right for --r3mix, etc, etc).

Basically, we're now back to the same old situation as before with the --dm-presets. Roel doesn't think the benefits are worth it because he can't hear them, and it doesn't matter how many other people do, it simply doesn't matter. He'll continue to state --r3mix is CD-Quality (incorrectly) and continue to advocate, if nothing else, a technically inferior preset.

I think the nature of the discussion now is actually more harmful than useful because continuing down this course is pretty much useless judging by past trials (I'm sure you remember...). Forward progress is what is necessary, and downplaying the merits of real improvements which cannot be denied serves no constructive purpose that I can see.

It would be nice to see some agreement from the other party on something which has been doing extremely well on all fronts and which has been proven multiple times to be superior, but I seriously doubt that is going to happen. Instead, I fear that the discussion will regress back into 2 divided camps and nothing more. It's a pity really, because in the end, its the users that suffer.
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johnicon
post Feb 15 2002, 13:25
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My $.02:
I found the r3mix website in May of 2001. For the first few months, I loved it. I was reading every post I could, even posting myself, though not much posting (I was a newbie back then:) ). But after around September, I lost interest because the forum was already bogged down in the same old (old by that time) issues about competing presets and command lines and what not. I came here as soon as you guys opened the site and was (and still am) pleased with the "free thinking" in these forums. Anyway, I think the point should be agreeing to disagree and pushing foward with improving things that we care about in the audio world as well as discussing new issues, instead of getting bogged down with no progress.
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brosselle
post Feb 15 2002, 14:46
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You know, I kind of liken this to the old vinyl LP vs. CD debate. For a long time, a lot of audiphiles were so concerned about this new digital thing, and how the "essence" of the music would be lost.

Well, I'm glad to say that most of them came around finally. Just try to find a Led Zeppelin album at Best Buy. And, just like r3mix, some audiphiles never came around. But so what, who cares. Let them keep listening to their scratchy albums on $1000+ turntables.

The point is, given enough time, I think the --alt-presets will become the standard....the norm. The r3mix preset will still be there for those that want it, but I don't think anybody will, save for a select few. It will eventually die out on it's own, due to it being an inferior technology. Evolution, ya know ;-)
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fewtch
post Feb 15 2002, 15:28
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For some reason, I suspect Roel will "come around" too. Dunno why, just intuition. He can still have his "special" --R3mix switch with a tweaking or two he might want to add himself... when he finds a good one, he'll probably decide to use --alt-preset standard with a few tweaks rolleyes.gif .

P.S... this "audiophile" uses LPAC for archival purposes (as in really backing up a music CD) and MP3 for general listening... that could potentially change to MPC if it catches on, but for now it's MP3 smile.gif.


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user
post Feb 15 2002, 23:08
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Hi,

during playing around with mp3gain, I found following:


- a mp3 song as source encoded with --alt-preset extreme or dm xtreme, containing very much only stereo frames, but this is not important.


1. maximize this song lossless ! with mp3gain, so that it does not clip.
Re-Encode it eg. with alt-extreme

2. lower the gain of the source.
Reencode it with same preset.


Result after reencoding:

1. the maximized song will contain mostly joint stereo frames.
2. the same song with lossless lower gain/volume will contain less js frames, more stereo frames !

Looking with Encspot:
Both songs have after reencoding nearly same bitrate, nearly same bitrate distribution.
Of course only nearly, but nearly exact the same....
That would be well....

But: the distribution of js and ms is very different.

My interpretation:

In alt preset extreme (i tested) there has been achieved that all songs result into a comparable average bitrate aorund 256 kbit, independent from gain.
But this was achieved by a compromise in stereo/joint stereo frames.
Loud songs have much joint stereo,
quiet songs much more pure stereo frames.

Even if it is the very same song just changed with lossless gains...

Of course I understand why it is like it is:
the gain change is lossless for one mp3, but reencoding works via wave.
And the 2 resulting waves of same song in my test are very equal, but have different gain....

And encoding these waves is different, because of ath and so on, , so if the quiet song gets encoded with alt extreme, that means target bitrate 256 kbit, and there is plenty space for quiet songs, encoder thinks: quiet parts are under ath....
so encoder offers bitrate for stereo instead of js.

Otherwise
loud song:
relative ath is different, quiet parts of loud song are listenable...
so much bitrate is required....
so use of js instead of stereo,
I think, that's it.


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Dibrom
post Feb 15 2002, 23:30
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QUOTE
Originally posted by user
1.  maximize this song lossless ! with  mp3gain, so that it does not clip.
Re-Encode it eg. with alt-extreme

2. lower the gain of the source.
Reencode it with same preset.


Result after reencoding:

1. the maximized song will contain mostly joint stereo frames.
2. the same song with lossless lower gain/volume will contain less js frames, more stereo frames !

Looking with Encspot:
Both songs have after reencoding nearly same bitrate, nearly same bitrate distribution.
Of course only nearly, but nearly exact the same....
That would be well....

But: the distribution of js and ms is very different.

My interpretation:

In alt preset extreme (i tested) there has been achieved that all songs result into a comparable average bitrate aorund 256 kbit, independent from gain.
But this was achieved by a compromise in stereo/joint stereo frames.


Sigh...

Ok, I'll try to explain this again.

First, I'd like to ask you a question, user. Are you hearing a deficiency in the stereo field? Are you hearing an error that you can verify repeatedly? If not, then why the incessent assertion that there must be something wrong because you don't think enough stereo frames are being used?

If you can actually hear a problem, I'm interested, if not, then you are rehashing this same issue needlessly once again.

Anyway...

There is one major flaw in your "interpretation". That is the fact that you completely disregard (or simply do not acknowledge) psychoacoustic effects in your statement that joint stereo is compromised. I've been seeing this a lot lately though.. people are making assumptions based on standard audio perception (and how they think things should work), without taking into account psychoacoustic effects.

It's a simple fact that the masking effect is more powerful at louder volumes. If you'd like, you could easily test this with one of the many samples which have shown "dropouts" with LAME in the past. What happens is that the louder you turn up the music, the less you can hear these dropouts. This is because the masking effect is increased and the flaws are actually hidden.

Now, in the case of dropouts, this is a bad thing.. and the --alt-preset solve that. However, the principle is the same with joint stereo. The --alt-presets have been tuned by ear, and verified by others, to coincide with what makes sense from a [b]psychoacoustic
point of view. They are tuned to sound good while being as efficient as possible. One of the ways the extreme preset is efficient is because it uses the athadjust to modify joint stereo thresholds in some cases. This does not mean that it compromises the stereo image. Again, this has been verified by others as well as myself via blind listening tests, not unsubstantiated assumptions that "there must be a problem because there are too few stereo frames".

So I'll state it once again. Either you hear a problem, or you don't. If you do, then let me know, otherwise stop worrying about it because for all intents and purposes the presets have been tuned to sound good, and that's what matters.
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user
post Feb 16 2002, 00:07
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Thank you, now it is clear.

yeah, as I spoke in simple model, I forgot masking in louder songs.

You see, for me it was/is still amazing that you and perhpas other developer have managed it to make routines more flexible.

Some days before Christmas there was everytime the same distribution of js/ss frames, independent if song was loud or quiet.
But at that time the bitrate changed a lot corresponding to gain.

I assume that altogether resulting quality has grown by this behaviuor, because now the quiet songs get more bitrate and if they are played more loudly then artefacts will be minimized.


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