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--ms 15, Any quality gain?
westgroveg
post Feb 5 2005, 10:47
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The following is a quote from user's hq-audio


QUOTE
What's the matter with --ms 15 switch ?

Answer: --ms 15 is the most advanced joint stereo/stereo mode in MPC. Quality (q) 5 uses ms11; q6 uses ms12; q7, q8, q9 use ms13 , q10 uses ms15 by default.
So, if you want to benefit from the addional safety offered by ms15, you need to add this switch.
Is there any possibility, that ms15 would reduce the quality of sound ?
No. The developer of MPC, Mr. F. Klemm, has confirmed, that adding ms15 can only improve the quality.
Are filesizes increasing by ms15 switch ?
For common music you will see nearly none increase of filesize. The bitrates will increase about 1-3 kbit/s at a level of q7-q8, so the bitrate increase is neglectable.
(Only certain (not all !) mono-music will have a remarkable bitrate increase, if you compare the encoding at e.g. q7 with q7 ms15.)
If you add ms15 to a lower quality level like q5, you will see a higher bitrate increase, but at this q-level the functionality, advantage of adding ms15 has been proven clearly.
What is the advantage of adding --ms 15 ?
If you listen to your stereo music via 4-6 speakers by applying Logic7/DPL2, you could suffer from artefacts, especially at lower q-levels like q5, q6. Adding --ms 15 even to q5, solves the problem. And the bitrate of q5 ms15 is clearly less than pure q6 !
So, adding ms15 to q-levels below q10, helps in every case to avoid artefacts, which might result by stereo/multichannel processing, separation.

I wanted to know if it makes sense to use --ms 15? are there any known problem samples that improve with the use of --ms 15? is this as stupid as using full stereo with LAME mp3?
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guruboolez
post Feb 5 2005, 10:50
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It seems that you're quoting the answer to your question.
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westgroveg
post Feb 5 2005, 10:54
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QUOTE (guruboolez @ Feb 5 2005, 09:50 PM)
It seems that you're quoting the answer to your question.
*


I don’t see were it says there is ABX proof that using –ms 15 with --insane or --Braindead improves quality
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guruboolez
post Feb 5 2005, 11:09
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Did you asked for ABX tests?

>>The developer of MPC, Mr. F. Klemm, has confirmed, that adding ms15 can only improve the quality.

Are you suggesting that developers should also proof their claims by positive blind tests results?
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westgroveg
post Feb 5 2005, 11:14
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QUOTE (guruboolez @ Feb 5 2005, 10:09 PM)
Did you asked for ABX tests?
*

QUOTE (westgroveG)
are there any known problem samples that improve with the use of --ms 15?



QUOTE
>>The developer of MPC, Mr. F. Klemm, has confirmed, that adding ms15 can only improve the quality.
Are you suggesting that developers should also proof their claims by positive blind tests results?

My question wasn't if there would be any reduction in quality it was if there would be any gain.
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guruboolez
post Feb 5 2005, 11:19
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http://www.hydrogenaudio.org/forums/index.php?showtopic=4109
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h.tuehn
post Feb 6 2005, 00:00
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QUOTE (guruboolez @ Feb 5 2005, 02:09 AM)
Did you asked for ABX tests?

>>The developer of MPC, Mr. F. Klemm, has confirmed, that adding ms15 can only improve the quality.

Are you suggesting that developers should also proof their claims by positive blind tests results?
*

You forgot to wink. smile.gif


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h.tuehn
post Feb 6 2005, 00:06
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I have a cold and am on cold medicine at the moment, so consider that and that I derived great pleasure out of looping the Mahler Chorus sample guruboolez provided in the 1.15t thread. Anyway, it tested tranparantly for me whereas I had been consistently identifiying a chanel distortion before.

Settings: --insane --ms 15

Be sure to place the --ms as the last argument or it gets ignored.


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westgroveg
post Feb 6 2005, 13:12
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QUOTE (guruboolez @ Feb 5 2005, 10:19 PM)


I missed that thread & have always remembered this rule:

QUOTE (List of recommended MPC settings)
--quality and --xlevel are safe to use.
However, don't use further switches to "tweak" the quality.
Some of them no longer work (like "--ltq fil") or have undesired effects on quality (like "--ms 0")!
For example, "--ltq fil" now defaults to the ISO ltq (threshold in quiet), the worst of them all.
Just use the --quality switch for fine-tuning, that's the best way.



Also tests performed by Frank Klemm don't seem to favor the use of --ms 15:

QUOTE (CiTay @ 4109)
Got an email from Frank Klemm (you too, user, thx):

He thinks that a new recommendation for surround encoding isn't necessary. For instance, he held another listening test where people didn't favor --ms 15, it was more like the opposite. People concerned with best "imaging" for their surround files should first try a higher quality setting, i.e. --quality 6 or --quality 7.


QUOTE (h.tuehn)
I have a cold and am on cold medicine at the moment, so consider that and that I derived great pleasure out of looping the Mahler Chorus sample guruboolez provided in the 1.15t thread. Anyway, it tested tranparantly for me whereas I had been consistently identifiying a chanel distortion before.

Settings: --insane --ms 15

Be sure to place the --ms as the last argument or it gets ignored.

So you tested with --insane, where able to ABX artifacts & --insane --ms 15 was transparent?

This post has been edited by westgroveg: Feb 6 2005, 13:17
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h.tuehn
post Feb 6 2005, 13:38
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QUOTE (westgroveg @ Feb 6 2005, 04:12 AM)
So you tested with --insane, where able to ABX artifacts & --insane --ms 15 was transparent?
*

Yeah, something like 72% probability after looping and 16 tries compared to .6% with insane alone. I'll be testing it again in a few days. It would be a nice fix. Only added a few bytes.


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Vertigo
post Jun 14 2005, 07:07
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QUOTE (h.tuehn @ Feb 6 2005, 04:38 AM)
QUOTE (westgroveg @ Feb 6 2005, 04:12 AM)
So you tested with --insane, where able to ABX artifacts & --insane --ms 15 was transparent?
*

Yeah, something like 72% probability after looping and 16 tries compared to .6% with insane alone. I'll be testing it again in a few days. It would be a nice fix. Only added a few bytes.
*



Yes, I would like to see some ABX results, as well as some ms 15 on and off multichannel tests, to see if it really is safe to use. Frank's backpeddling is really throwing me off here.
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user
post Jun 24 2005, 14:44
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QUOTE (Vertigo @ Jun 14 2005, 07:07 AM)
..., to see if it really is safe to use.  Frank's backpeddling is really throwing me off here.

Which backpeddling ?


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Vertigo
post Jul 1 2005, 17:37
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At first, it is said it provides better quality....but in multichannel tests the results do not reflect that. Sounds like --ms15 is not safe for midbitrate multichannel.
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Yaztromo
post Jul 1 2005, 18:28
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Possibly -ms 15 would benefit quality 5 and below I think. Maybe even Q6. Xerophase noticed and proved deteriation of soundstage at these levels.

This thread is amazing: http://www.hydrogenaudio.org/forums/index....topic=11278&hl=

Unfortunately he didn't test -ms 15 much, so the jury is still out as far as stereo recordings go.
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user
post Jul 1 2005, 22:32
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@Vertigo: Can you provide a link, please ?


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Vertigo
post Jul 2 2005, 20:21
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user, all information is provided in this thread. Read back.
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user
post Jul 3 2005, 13:54
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Vetigo, I read all links in here. If you have read the topics, you find me even participating in the old and relevant topics.
So, where is "F. Klemm backpeddling" ?

This post has been edited by user: Jul 3 2005, 13:55


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Vertigo
post Jul 5 2005, 17:03
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It was stated by Mr Klemm, that --ms15 only improves quality. Yet, in regards to his multichannel listening tests, he goes against this by stating --ms15 was not favorable for imaging.

Now, not in regards to Mr. Klemms, comments, it was found that in some instances q5 had a narrow sound stage. Testing with --ms15 did help with the situation (as I recall). Now, this test was not multichannel, but stereo.

To me, I see this as conflicting. The independant tests provided by Frank disproves his --ms15 statement, while the ones proformed on HA shows that it does help.

To futher add to confusion, we are told not to use switches aside from --xlevel, which is hardcoded now (but I keep anyways cause I am paranoid).

So, what I think what now must be done is a multichannel listening test for q5, q6, and q7, alternating with --ms15 to correct the confusion with conflicting statements.

Oh, and one last bit, I use 4 channels, and q6, no --ms15 switch, and the imaging does seem intact for casual listening.
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Vertigo
post Jul 5 2005, 17:04
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And I know of your involvement user, and I greatly respect you. =)
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Vertigo
post Jul 5 2005, 17:10
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QUOTE (guruboolez @ Feb 5 2005, 02:09 AM)
Did you asked for ABX tests?

>>The developer of MPC, Mr. F. Klemm, has confirmed, that adding ms15 can only improve the quality.

Are you suggesting that developers should also proof their claims by positive blind tests results?
*




I remember when 128 kbps MP3's were CD quality. rolleyes.gif





....sorry, I had to make a audiophile funny...I am in that kind of mood.
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user
post Jul 6 2005, 19:08
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westgroveG: Also tests performed by Frank Klemm don't seem to favor the use of --ms 15:


QUOTE(CiTay @ 4109)
Got an email from Frank Klemm (you too, user, thx):

He thinks that a new recommendation for surround encoding isn't necessary. For instance, he held another listening test where people didn't favor --ms 15, it was more like the opposite. People concerned with best "imaging" for their surround files should first try a higher quality setting, i.e. --quality 6 or --quality 7.






Now I see, to which statements you were reflecting, Vertigo, by "Klemm backpeddling", that was the reason, I wanted to be sure, which statement you meant, or you even had more informations, which I didn't know so far.

well, my problem with the listening test, which lead to the contradictional minds, is following: It is not published, no test environment, no AB or ABX, or ABchr tests, any descriptions published ever. The only statement, which had evidence for me, is Klemms clear sentence, that --ms 15 cannot reduce quality.
Even the kind of surround, which was tested by Klemms friends, is unknown, stereo, DPL, DPL2, Logic7 ? there is only written "surround".

And then we have the things opposite to this "surround --ms 15 test":
- Klemms own theoretical statement from his own developer knowledge, "--ms 15 cannot harm quality"
- that surround/--ms 15 test in that HA topic, where even 1 guy listened only to rear channels, though this test method isn't totally valid either, of course.
- Though at that time , years ago meanwhile, I played a lot with my Harman Kardon AVR 5000 with Logic 7 decoder, and came to the result, that --ms 15 does good, have made archive backups of my music in Lossless and as small doubled security backup, for laptop, too, in MPC qualities 7-8, but always with --ms 15 added. Haven't listened any flaw.
Because I had the usage as backup for a lot of music in mind, and I have a great listening room with 4 identical speakers in a lot meters distance to each other with the new Harman Kardon and the cool Logic7 (not to compare with old-fashioned DPL), I wanted to be sure, what happens, if enhanced joint stereo mode --ms 15 is used, to be safe, not to get artefacts introduced by --ms 15 at q-levels below q10.

well, maybe at mid-bitrates, ie. q5, music might sound different by --ms 15 or not, but what version would be "better" ?
Read the rather unclear wording "people didn't favor --ms 15, it was more like the opposite." Which indicates, that the people had divided opinions, maybe 1/3 vs. 2/3 of the testers, even 51% vs. 49% would be possible by these words ? Well, due to the "short", unsufficient test description, that test cannot claim to contain the 1 and only truth.
Additionally this statement has to be seen in its context, as it was written during a discussion with Citay, Klemm, me, whether we should mention the --ms 15 in the recommended settings topic regarding surround encoding/decoding.
The recommended settings topic about MPC with the hint, not to add other switches than xlevel, is made for newbies, who have found luckily MPC, and to give them a quick start with some sort of warranted success. So, that they don't waste time, and reduce quality by trying out various switches.
People who know more, will find the MPC extras, well there aren't many, due to the extraordinary quality of MPC.
In the end, we decided to leave --ms 15 away from the beginners' topic, as due to the high MPC quality, improvements are always small. And yes, who isn't satisfied with q5 due to listening artefact training, good HiFi, good ears (no damage by concerts, discos, hehe), will go for q6, q7, q8 anyways, to reduce his listened problems, and the joint stereo mode is more advanced by default anyways, going from q5 to q6, then to q7-q9.

Of course, more true test results, opinions with q5, q5 ms 15, would be interesting to know over a wider variety of people, tastes, music hardware.

This post has been edited by user: Jul 6 2005, 19:16


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2Bdecided
post Jul 6 2005, 23:21
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I'd love to know how, in a VBR encoder which has no upper bitrate limit, any switch which increases the bitrate of the side channel and/or reduces the use of mid/side stereo, can decrease quality?

I can think of hypothetical cases where there could be a problem (e.g. very near mono, where the resulting constant toggling of stereo modes could be just audible in the back speakers only), but given the very real and loud distortion that a bitrate-starved side channel causes in matrix surround decoders (when listening to the back speakers only) I can't believe it's bad to try to solve this real issue.

By using ms 15 you're throwing more bits at it. You shouldn't be making anything worse. At least in theory. It's not like in mp3 where it can run out of bits at the 320kbps maximum.

Cheers,
David.
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user
post Jul 7 2005, 10:05
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yes, that was my initial point I wanted to know, how the --ms 15 switch was built., ie. whether it adds always, or whether ms15 would "eat" bitrate from the rest of the music.
--ms 15 behaviour with mono music:
sometimes no bitrate increase compared to the default setting, with certain mono music, you pump up the bitrate remarkable.


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Vertigo
post Jul 8 2005, 18:56
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I am using an MCS series amplifier, 2255, It was made exclusively for JC Penny. I suppose this was HiFi stereo in the 80's. I use it to drive a pair of Kenwood speakers, with 3 components, the woofer is 15". I also drive a pair of Radioshack Pro Series (Pioneer renamed) 8". and a pair of high end tweeters that ar suppose to reach 26 khz. That's for my front. I have for my rear channel a Creative Inspire 4.1 system. I use it for enviromental effects mostly.

In my casual listening I find the imaging to be rather pleasant at --q6. I don't know How I can further test imaging blindly to determine the effects of --ms15.
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