HydrogenAudio

Lossy Audio Compression => MP3 => MP3 - General => Topic started by: daniel.ok on 2012-09-19 16:00:04

Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: daniel.ok on 2012-09-19 16:00:04
I have a small problem here: I want to re-encode my MP3's from 320CBR to -V2 with dbpoweramp (lame 3.99.5) but here is the trick: I have MP3's at 320CBR Stereo and MP3's ar 320CBR Joint Stereo. All I want is that Stereo\Joint Stereo remains the same, only quality modify to -V2. So, when I choose from dbpoweramp\advanced\channels I choose [auto] but this modify my MP3 always to Joint Stereo. Also I choose Stereo (auto) (CD) but it's the same, final MP3 is Joint Stereo from Stereo source.
What should I pick from channels option? (Force Stereo I suppose it's not the way to go, or is?) I've tested another ripper/converter and it was more simple: when I choose Joint Stereo - MP3 is JS, when I choose Stereo - MP3 is Stereo.

Also I have one more important question: It is right what I do? (keep the same type after re-encoding, Stereo - Stereo,  Joint Stereo - Joint Stereo) (*please note that I convert MP3 to MP3)

Thank you, Daniel
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: greynol on 2012-09-19 16:38:18
http://wiki.hydrogenaudio.org/index.php?title=Joint_stereo (http://wiki.hydrogenaudio.org/index.php?title=Joint_stereo)
http://wiki.hydrogenaudio.org/index.php?title=Transcoding (http://wiki.hydrogenaudio.org/index.php?title=Transcoding)
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: daniel.ok on 2012-09-19 17:24:08
http://wiki.hydrogenaudio.org/index.php?title=Joint_stereo (http://wiki.hydrogenaudio.org/index.php?title=Joint_stereo)
http://wiki.hydrogenaudio.org/index.php?title=Transcoding (http://wiki.hydrogenaudio.org/index.php?title=Transcoding)



All I want to ask is this:

It's clearly that is better to encode JOINT STEREO from lossless formats (CD's, Flac, etc), BUT I ask if it's also better to encode JOINT STEREO from another MP3 which is STEREO !!! I'm wondering if it's better to encode that MP3 also in STEREO.

what do you think guys?
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: Manlord on 2012-09-19 18:34:02
You shall not re-encode from mp3 to mp3.
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: daniel.ok on 2012-09-19 18:44:17
You shall not re-encode from mp3 to mp3.



i know mate the discussion regarding re-encoding from mp3 to mp3, I know it's better to rip directly from lossless BUT regarding to my problem (JS-JS, Stereo-Stereo) how is better?
thanks!
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: greynol on 2012-09-19 18:51:45
It's only a problem if you can distinguish a difference between the two as you would typically use them.

Unless you're doing some kind of channel-based post-processing you are probably better off using joint-stereo regardless of the source so long as it has content in the center.

Before you ask any other questions about quality, make sure you read this if you haven't already:
http://www.hydrogenaudio.org/forums/index....showtopic=16295 (http://www.hydrogenaudio.org/forums/index.php?showtopic=16295)
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: pdq on 2012-09-19 18:52:47
Joint stereo is theoretically better, even when transcoding from forced stereo, but at those bitrates (-V2) the difference is unlikely to be audible.

EDIT: greynol beat me.
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: daniel.ok on 2012-09-19 19:07:38
Joint stereo is theoretically better, even when transcoding from forced stereo, but at those bitrates (-V2) the difference is unlikely to be audible.

EDIT: greynol beat me.



I don't know if I do a  "channel-based post-processing" or transcode from FORCE STEREO, i'm assuming that I re-encode a MP3's that follow this path:

LOSSLESS (CD's, FLAC..) - rip with lame in STEREO MODE at 320CBR - My rip !  Now, I don't know if to use JS or Stereo when I rip this .... sorry for posting so puerile stuff for you guys.

Thank you!
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: pdq on 2012-09-19 19:11:54
Do these files decode into some kind of surround sound? If not then use JS.
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: greynol on 2012-09-19 19:13:26
Post-processing such as Dolby surround decoding or karaoke-style applications.

Other than that, we've already answered your question with all the information you could possibly need.

In case it helps, let me put it even more plainly: use joint-stereo even if the original file was in stereo.

EDIT: pdq beat me this time around, lol.
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: daniel.ok on 2012-09-19 19:16:28
Post-processing such as Dolby surround decoding or karaoke-style applications.

Other than that, we've already answered your question with all the information you could possibly need.

In case it helps, let me put it even more plainly: use joint-stereo even if the original file was in stereo.

EDIT: pdq beat me this time around, lol.



greynol, pdq,  thanks mates! I stick to JS then!
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: kornchild2002 on 2012-09-19 19:16:59
Your question has been previously answered regarding the use of stereo and joint stereo (hint: its the second option).  You were pointed to the Wiki articles as they contained information to help you determine the proper settings along with gaining insight into what you were asking.  People often come on and ask "What's the best setting for X encoder and A, B, and C type of music?"  There isn't an absolute answer for anyone.  However, it is generally best to use the default Lame settings unless you are experiencing problems (that can be heard in proper blind ABX testing) and insist on tuning them out.  Lame is also a great VBR mp3 encoder and you can likely get away with not using such an insanely high bitrate.  Again, unless you can properly ABX it, 320kbps VBR is probably going to be overkill.  I suggest starting out with your source lossless material and use the -V 5 setting (maybe even -V 6).  Conduct a blind ABX test with a few songs comparing the source lossless versions to their lossy counterparts.  "Pass" the test and encode the material at a higher setting.  Keep progression (-V 6 to -V 5, -V 5 to -V 4, -V 4 to -V 3, etc.) until you fail the test.  Here is is a link covering the ABX process:
http://wiki.hydrogenaudio.org/index.php?title=ABX (http://wiki.hydrogenaudio.org/index.php?title=ABX)

Then again, I know how you hate getting links as answers so I am not expecting you to read it.
Title: Transcoding from simple stereo MP3, should destination use simple too?
Post by: daniel.ok on 2012-09-19 19:21:42
Your question has been previously answered regarding the use of stereo and joint stereo (hint: its the second option).  You were pointed to the Wiki articles as they contained information to help you determine the proper settings along with gaining insight into what you were asking.  People often come on and ask "What's the best setting for X encoder and A, B, and C type of music?"  There isn't an absolute answer for anyone.  However, it is generally best to use the default Lame settings unless you are experiencing problems (that can be heard in proper blind ABX testing) and insist on tuning them out.  Lame is also a great VBR mp3 encoder and you can likely get away with not using such an insanely high bitrate.  Again, unless you can properly ABX it, 320kbps VBR is probably going to be overkill.  I suggest starting out with your source lossless material and use the -V 5 setting (maybe even -V 6).  Conduct a blind ABX test with a few songs comparing the source lossless versions to their lossy counterparts.  "Pass" the test and encode the material at a higher setting.  Keep progression (-V 6 to -V 5, -V 5 to -V 4, -V 4 to -V 3, etc.) until you fail the test.  Here is is a link covering the ABX process:
http://wiki.hydrogenaudio.org/index.php?title=ABX (http://wiki.hydrogenaudio.org/index.php?title=ABX)

Then again, I know how you hate getting links as answers so I am not expecting you to read it.



the reason I avoid link-answers is that my english it's not quite good and it's possible not to understand all those specific terms. anyway, thank you, nice thing from you to answer me!