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Author Topic: What is the difference between "Stereo" and "Joint Stereo"?  (Read 5760 times)

Lucy

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1. What is the difference?

2. which one has better quality?

3. Can MJ have "Joint-Stereo" option in future, if JS is better?
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KingSparta

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RE:What is the difference between
« Reply #1 on: July 02, 2002, 05:11:56 pm »

Joint Stereo Is Better.

Because It Will Shift Lets Say Data From The Left Side To The Right Side If The Right Side Is Not Full Of Data.

Basicly It Saves Room When The Mp3 File Is Saved, It Does Not Make It Sound Better Or Worse.
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Trelane

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RE:What is the difference between
« Reply #2 on: July 02, 2002, 05:17:30 pm »

Stereo consists of two seperate streams of data for each channel (left and right). Joint Stereo is a term used with MP3 meaning that a stereo mode which is the best for the frame is chosen. The modes it can choose from are: mid/side stereo and intensity stereo. Both use methods of decorrelating the data so that it can be packed into a smaller space (much more efficient than plain stereo).

Intensity stereo is used only at low bitrates, and as far as I know, only by Fraunhofer encoders. Mid/side stereo is used usually when intensity stereo is not, unless you manually specify stereo when encoding. Intensity stereo noticably degrades the stereo image, while mid/side stereo usually has no ill effects.

Because of the nature of MP3, I recommend using Joint Stereo. The cost? There may be a slight degradation in stereo image, but I doubt you'll notice. The benefits? It may lessen the appearance of nasty, noticable artifacts.

MJ uses the LAME encoder, and most likely uses JS by default. Don't quote me on that, though.

Mike
Listening to: '1.19' from 'Unleashed Memories' by 'Lacuna Coil' on Media Jukebox
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JorgeGVB

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RE:What is the difference between
« Reply #3 on: July 03, 2002, 07:46:18 am »

How are you determining you have Joint Stereo MP3s or not?  The reason I ask was I was playing around with EncSpot (available for free at http://www.guerillasoft.com/EncSpot2/download.html) and within the program I double clicked on an MP3 which identified the MPS as Joint Stereo.  It seems most of my MP3s are Joint Stereo.  However, I noticed the MP3s that I have ripped since upgrading to MJ 8.0 do not appear to be Joint Stereo.  Is there a way to control this within MJ?

FYI...  EncSpot is an application which reports useful facts about your MP3 collection. One good feature is its ability to determine which encoder was used to encode each file. It will also give you a general idea of the audio quality of the file.
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JorgeGVB

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RE:What is the difference between
« Reply #4 on: July 04, 2002, 09:11:08 am »

bump
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KingSparta

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RE:What is the difference between
« Reply #5 on: July 04, 2002, 09:17:47 am »

If you click on a file, Properties, and then click on the format tab

the 3rd info line will tell you how it was encoded.
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jolo

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Join stereo is not "better", it depends
« Reply #6 on: July 05, 2002, 05:57:18 pm »

Done a lot of research on this. Joint stereo should have a "better" sound when encoding MP3s with lower bit rates. Meaning 128 or under. Joint stereo is to take advantage of of similarities between the R and L channels and allows more bits to be used in other areas. There is less speration, but a better sound.

For high quality encoding, bitrates 160 and above joint stereo should NOT be used. As a matter of fact, it definately could have a negative effect, like distortion and loss of stereo seperation. There are are the bitrates to go around so you don't have to sacrifice the stereo seperation.

Bottom line, if I am encoding up to and including 128, I will use joint stereo. For 160 and above (where I normally encode), I use stereo

If you want some real scientific stuff, you can go to the Fraunhofer-Gesellschaft web site http://www.iis.fhg.de/amm/techinf/layer3/. There is a good definition there of joint stereo which is
"Joint stereo coding takes advantage of the fact that both channels of a stereo channel pair contain far the same information. These stereophonic irrelevancies and redundancies are exploited to reduce the total bitrate. Joint stereo is used in cases where only low bitrates are available but stereo signals are desired. "
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joe|PLS|mama

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RE:What is the difference between
« Reply #7 on: July 07, 2002, 01:19:04 am »

jolo wrote "For high quality encoding, bitrates 160 and above joint stereo should NOT be used."

The mp3 encoder included with MJ is based on the LAME encoder.  Unless you are encoding using a custom command line, joint stereo is used by default no matter what bitrate you are using.  Not using joint stereo when encoding with LAME will generally give lower quality.  Do a search at the Hydrogen Audio Forums for a more indepth explanations. http://www.hydrogenaudio.org/forums/

from http://www.hydrogenaudio.org/forums/showthread.php?s=&threadid=759

"While this may be true for a few popular encoders which have screwed up Joint Stereo implementation (Fraunhofer (FHg), Xing, etc), this is not true for LAME."

from http://users.du.se/~kdo/mpc/mp3misconcept.htm

"The state-of-the-art encoders (Lame, mppenc, aacenc, oggenc) exploit the so called smart joint stereo algorithms, which practically never damage stereo image at higher bit-rates. Please refer to more technical explanations by the Lame alt-preset developer and also to this discussion of safe js."
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Lucy

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RE:What is the difference between
« Reply #8 on: July 07, 2002, 03:49:46 am »

I want to ask a silly question........but i really am curious....

let say...I download a song from Emusic. It is 128kbps. And I decode it to WAV format. Then I encode it again to 320kbps.

Would I then listen to better quality?

I hope you guys forgive my foolish question.......
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sekim

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RE:What is the difference between
« Reply #9 on: July 07, 2002, 03:58:08 am »

Lucy,

No. It just throws away more information. Better off leaving it as is.
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joe mama

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RE:What is the difference between
« Reply #10 on: July 07, 2002, 10:24:41 am »

When you decode a 128 mp3 back to wave, you end up with a wave that sounds exactly like the 128 mp3, not like the original.  If you re-encode to mp3 even at 320, that process will throw out even more audio data and you will end up with an mp3 with even lower sound quality than the original 128 you started with.

Never re-encode, and if you do, don't share them.
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peleton

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RE:What is the difference between
« Reply #11 on: July 07, 2002, 10:45:38 am »

>"The state-of-the-art encoders (Lame, mppenc, aacenc, oggenc) exploit the so called smart joint stereo algorithms, which practically never damage stereo image at higher bit-rates.

Actually if you want, you can use oggenc (Ogg Vorbis) at Quality 5 (approx 160kbps) and above which uses LOSSLESS stereo coupling. There is also practically no low-pass filtering from this quality level upwards.

p.
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JorgeGVB

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RE:What is the difference between
« Reply #12 on: July 07, 2002, 12:53:26 pm »

I have went back and looked at my MP3 files for the past year or so and some are Joint Stereo and some are not.  I have about 3,000 files.  It seems like most of the more recent files are not Joint Stereo.  I am not sure why this is, since I only rip with MJ using LAME @ 192 Bitrate.  Is there a way to select Joint Stereo?
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joe mama

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RE:What is the difference between
« Reply #13 on: July 07, 2002, 02:30:01 pm »

What settings are you using for the encoder?  I would do it this way:  go to Options, then Encoding, choose MP3 Encoder (not MP3 Encoder VBR), under quality choose custom, click the Advanced button and where it says Command Line put "--alt-preset cbr 192" (without the quotes).  This should give you the best quality for that bitrate.
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joe mama

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RE:What is the difference between
« Reply #14 on: July 07, 2002, 02:44:44 pm »

Ooops, forgot. In order to use the settings I suggested in my previous post, you must use the lame.exe, which is not included in MJ.

Download the zip here http://home.pi.be/~mk442837/

unzip it and put the file lame.exe in your MJ plug-ins folder.

I just tried it and got a 192 file with joint stereo.
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