Topic: mp3s - vbr vs cbr? (Read 8992 times)

nickharambee · « **on:** April 03, 2004, 03:14:26 am »

hello,

can someone tell me if i am likely to get better quality mp3s by encoding as '320 kbps cbr' or 'high vbr'. i have tried converting the same track to both and the 'high vbr' file is around 2/3 of the size of the cbr file. in media centre it gives the vbr file a rating of 205 kbps. however, when i go the folder where the files are, there it gives a kbps rating of over 400 for the vbr file. so what might be going on here? i like the idea of a 400+kbps file at 2/3 size, but am i really getting better quality at a smaller size? also has anyone heard of an 'audiophile vbr' setting, or is the same as the 'high vbr' setting?

thanks, nick.

rocketsauce · « **Reply #1 on:** April 03, 2004, 04:39:45 am »

Quote

i like the idea of a 400+kbps file at 2/3 size

That's impossible. Higher bitrate = larger filesize.

Anyway, there's no such thing as a 400kbps mp3. It's showing that way because Windows doesn't know how to read vbr files correctly. The bitrate you see in MC for vbr mp3s will (generally) be the correct bitrate, but it is an average bitrate.

For all practical purposes, 320kbps cbr is the highest quality setting for mp3.

Rob

Alex B · « **Reply #2 on:** April 03, 2004, 09:50:35 am »

Quote from: nick_harambee on April 03, 2004, 03:14:26 am

can someone tell me if i am likely to get better quality mp3s by encoding as '320 kbps cbr' or 'high vbr'...
...also has anyone heard of an 'audiophile vbr' setting, or is the same as the 'high vbr' setting?

Well, you could start here: http://www.hydrogenaudio.org/index.php?showforum=15. You get everything you need to know about MP3 at those forums.

I use LAME 3.90.3 as an external MP3 encoder with MC. Usually my setting is "alt preset extreme", which is the highest quality VBR setting with that encoder. I'm not sure if "VBR High" setting with the internal encoder is as good. Maybe someone else can tell more about this.

When comparing "alt preset extreme" and "alt preset insane" (highest quality 320 kbit/s CBR setting) the audible difference is minimal.

With "insane" setting low pass filter is set to about 20.5 kHz and with "extreme" the limit is about 19.5 kHz (if you can hear the difference). On the other hand I think that there is more room for high quality treble when it's cut off 1 kHz lower in VBR "extreme". It goes up to 320 kbit/s whenever needed anyway.

It's the high frequencies area where kbits are needed. Bass frequencies in 128 kbit/s file sound pretty much the same as in higher quality MP3 files.

GHammer · « **Reply #3 on:** April 03, 2004, 12:22:26 pm »

Pick a couple of selections that you know well and that have a mix of instruments and levels.

Rip them using both settings and see which you like better.

'Cause it's your ears you are trying to please.

Personally I use LAME 3.95-1 with this command line.
--preset extreme --scale 1

I just drop the 3.95-1 exe into the MC directory.

zevele10 · « **Reply #4 on:** April 03, 2004, 01:37:47 pm »

I did some MP3 for Mastiff in MC

MP3 VRB

Hight - advanced settings: Hight Quality.

The quality was really really good.

I was impress.

Not to the point to change from MPC to MP3 , but sound was excellent.

Alex B · « **Reply #5 on:** April 03, 2004, 06:39:53 pm »

I did some testing with a small acoustic song (wave -> mp3):

External Encoder: LAME 3.90.3

parameters %IN %OUT --alt-preset standard
results 143 kbit/s VBR file, min. bitrate 128 kbit/s, max. 320 kbit/s, Joint Stereo

parameters %IN %OUT --alt-preset extreme
results 156 kbit/s VBR file, min. bitrate 128 kbit/s, max. 320 kbit/s, Joint Stereo

parameters %IN %OUT --alt-preset insane
results 320 kbit/s CBR file, Joint Stereo

Internal Encoder (MC uses LAME 3.93)

VBR, Quality: High, Advanced: High Quality
results 152 kbit/s VBR file, min. bitrate 80 kbit/s, max. 320 kbit/s, Stereo

CBR, Quality: 320, Advanced: High Quality
results 320 kbit/s CBR file, Stereo

What surprises me, is that the internal encoder uses Stereo mode instead of Joint Stereo. It's well known fact that Joint Stereo mode with LAME gives the best results.

Anyway, it was quite impossible to hear any differences between those samples.
In listening test I used digital connection from the Terratec DMX 6fire soundcard (real 44.1 kHz, no resampling) to an upper class HT-receiver and the speakers were also quite high quality.

Charlemagne 8 · « **Reply #6 on:** April 03, 2004, 08:13:21 pm »

The way that I understand the theory, and there are some here that understand it much better than I, High Quality VBR will yield basically the same audio quality as 320 CBR but with a smaller file size.

And Rocketsauce, I KNOW that there are 384 KBPS MP3s out there and there are rumors of a 640KBPS MP3 encoding. The MAD plugin for Winamp will supposedly play both but my question would be "Why?". A file of that quality (640) would approach the file size of ape, thereby losing the only advantage of an MP3 file.

CVIII

JimH · « **Reply #7 on:** April 03, 2004, 08:54:21 pm »

Go APE.

rocketsauce · « **Reply #8 on:** April 04, 2004, 12:19:33 am »

Quote

And Rocketsauce, I KNOW that there are 384 KBPS MP3s out there and there are rumors of a 640KBPS MP3 encoding.

Yeah, but they can't be played by MC. And, as far as I know, there are no portable devices that play them either.

Rob

nickharambee · « **Reply #9 on:** April 04, 2004, 10:21:41 am »

ok, so my main use for converting to high quality mp3 from ape is that i want to use some of my music for djing using pcdj and ape files are not supported by this program. i have also been led to believe that vbr are not ideal for use with this program either, so i guess i am limited to cbr mp3 files. this thread seems to suggest that i am better off using an external lame encoder for converting to 320 kbps files, as this would be encoded as joint stereo, which would be better quality.

if this is so, can someone please advise me as to how to set up this encoder within mp3, and where is the best place to get it from

thanks

nick.

xen-uno · « **Reply #10 on:** April 04, 2004, 10:33:30 am »

For 320 CBR, use MP3 Encoder VBR, choose Custom for quality, then click on the Settings button (or whatever it is to the right), and put in the following...

--alt-preset insane

> i have also been led to believe that vbr are not ideal for use with this program either

What program? MC? The VBRs will sound as good as any CBR and save you space to boot. They are ideal for any program. As outlined above, there are two more presets that have been mentioned already (in descending quality)...

--alt-preset extreme
--alt-preset standard

R_x

nickharambee · « **Reply #11 on:** April 04, 2004, 10:36:49 am »

i have been led to believe that vbr files don't always work well with pcdj, a sofware based dj program, particularly when looping sections of a track

nick.

also, how do i get the external lame encoder, which encodes as joint stereo to work in mc9?

xen-uno · « **Reply #12 on:** April 04, 2004, 11:15:37 am »

With looping, it may probably more precise with a CBR file than with VBR...but I would test that yourself with a few VBR's. In this day & age, PCDJ should handle both types just swell.

> how do i get the external lame encoder, which encodes as joint stereo to work in mc9?

Are you saying it doesn't? The presets use joint stereo (maybe not Insane) which is OK (sounds as good as Stereo with some bit savings). MC9/9.1 use LAME 3.92, which is a very good version. You don't need to use LAME as an external encoder, use MP3 encoder VBR as outlined above. If you insist on using Lame as an EE then I'll have to get back to you...I'm at home with my MJ machine.

R_x

nickharambee · « **Reply #13 on:** April 04, 2004, 11:20:18 am »

in his post above in this thread alex b states that the internal lame encoder with mc does not use joint stereo, which is the preferable encoding method? is this not true?

nick.

Alex B · « **Reply #14 on:** April 04, 2004, 11:24:25 am »

Quote from: nick_harambee on April 04, 2004, 10:36:49 am

also, how do i get the external lame encoder, which encodes as joint stereo to work in mc9?

You can get LAME e.g. here:

http://www.rarewares.org/files/mp3/lame-3.90.3.zip

Put LAME.EXE to some folder and set MC to use external encorder.
EXE path: e.g. C:\Program Files\L3903\lame.exe
Parameters: %IN %OUT --alt-preset insane

You can also use that custom parameter with the internal encoder and that makes it use 320 kbit/s CBR with Joint Stereo.

Encoder: MP3 Encoder
Quality: Custom
Advanced: Command Line: --alt-preset insane

Alex B · « **Reply #15 on:** April 04, 2004, 11:31:57 am »

Quote from: nick_harambee on April 04, 2004, 11:20:18 am

in his post above in this thread alex b states that the internal lame encoder with mc does not use joint stereo, which is the preferable encoding method? is this not true?

nick.

I have found that default is "Stereo" (at bitrates 320 CBR and High Quality VBR),
but when you use those "--alt preset" parameters setting is "Joint Stereo".

xen-uno · « **Reply #16 on:** April 04, 2004, 11:40:00 am »

Excerpt from lame_392.zip (basic.html)...

* -m s/j/m stereo mode
Joint-stereo is the default mode for stereo files with VBR when -v is more than 4 or fixed bitrates of 160kbs or less. At higher fixed bitrates or higher VBR settings, the default is stereo. It looks like CBR's are always stereo.

stereo
Normal stereo mode.

joint stereo
In this mode, the encoder will make use of a correlation between both channels in order to achieve higher compression. This will enhance the quality of constant bitrate recordings, and reduce the size of variable bitrate recordings.

In a nutshell, you can override stereo/joint stereo selection of any preset...but there is no reason to...these presets have been rigourously tested.

More LAME explained here...
http://www.hydrogenaudio.org/show.php/showtopic/203

R_x

nickharambee · « **Reply #17 on:** April 04, 2004, 11:42:05 am »

thanks for your messages alex.

is there any advantage then to using an external lame encoder if i can set the internal encoder to encode to joint stereo? if i have been using the default cbr 320 kbps setting (i.e. encoding to stereo), will i notice a difference in quality, or will there just be a difference in file size?

nick

nickharambee · « **Reply #18 on:** April 04, 2004, 11:51:32 am »

thanks for your message xen-uno.

so let me see if i have got this right. when i choose default 320 kbps setting in mc9, it encodes in normal stereo mode, and this is felt to be the best stereo mode for this setting. it is possible however to alter this to joint stereo mode by choosing 'custom', 'advanced' and 'alt preset insane'. whether there is any advantage to this seems to be questionable. alex b seems to suggest that joint stereo mode is generally preferred, but from what you are saying this may only be beneficial at lower bit rates?

have i got this right?

thanks, nick.

xen-uno · « **Reply #19 on:** April 04, 2004, 11:54:10 am »

Internal encoder is based on Lame 3.92...external is based on whatever you reference. You should stick with the presets (--alt-preset insane over just 320 CBR)...do a little testing to see if YOU can hear a difference. As Alex said...the VBR presets are JS which override the logic written in the excerpt.

R_s

edit: There's no reason to change the stereo mode...it would provide minimal space saving on a file encoded to 320 CBR. If you do use -api (and you should), then set it as outlined in my first post (via MP3 encoder VBR).

nickharambee · « **Reply #20 on:** April 04, 2004, 11:58:11 am »

are the cbr presets also joint stereo? (i am being recommended to use cbr for use with pcdj instead of vbr)

nick

xen-uno · « **Reply #21 on:** April 04, 2004, 12:05:34 pm »

CBR & CBR presets are stereo (vs JS)

nickharambee · « **Reply #22 on:** April 04, 2004, 12:17:32 pm »

ok, so now i am a little confused. above alex b suggests that when i setup CBR presets (such as alt preset insane) they use joint stereo, and now you are saying that it is only VBR that uses joint stereo. i quote alex b:

"You can also use that custom parameter with the internal encoder and that makes it use 320 kbit/s CBR with Joint Stereo.

Encoder: MP3 Encoder
Quality: Custom
Advanced: Command Line: --alt-preset insane"

(sorry i don't know how to paste quotes)

nick.

Sauzee · « **Reply #23 on:** April 04, 2004, 12:23:23 pm »

AlexB

When I use MC mp3 VBR, it always uses joint stereo

Alex B · « **Reply #24 on:** April 04, 2004, 12:29:00 pm »

Quote from: nick_harambee on April 04, 2004, 11:42:05 am

thanks for your messages alex.

is there any advantage then to using an external lame encoder if i can set the internal encoder to encode to joint stereo? if i have been using the default cbr 320 kbps setting (i.e. encoding to stereo), will i notice a difference in quality, or will there just be a difference in file size?

nick

If you use CBR 320 there will be no difference in file size. Those switches are only for tweaking quality. Maybe you don't hear any difference. The quality is quite high anyway. Some people think it's transparent at those bitrates.

The only reason to use external LAME 3.90.3 over the internal encoder might be that 3.90.3 is claimed to be the most tested version. But differences are minimal and it's not likely that you can find any by listening.

Hydrogenaudio MP3 FAQ is also a good starting point:
http://www.hydrogenaudio.org/index.php?showtopic=7516&#entry74068

P.S.

Quote

are the cbr presets also joint stereo?

If you use MC preset quality: 320, you get "Stereo"

If you use custom quality with advanced parameter: --alt preset insane you get CBR 320 and "Joint Stereo". I just tested that with MC10 internal encoder, which is LAME 3.93 (that is written inside MP3 file many times). By the way, make no mistake: LAME 3.93 and 3.903 are different versions.

nickharambee · « **Reply #25 on:** April 04, 2004, 12:39:01 pm »

thanks, alex. i think mc 9.1.316 uses lame 3.91 - presumably i'd also get joint stereo with this, using the setting you mention. maybe the confusion i am having between yourself and xen-uno is that presets are the standard settings, 128, 192, 320.... and these are encoded as normal stereo. it is the custom alt presets that are joint stereo? incidentally, is there any way of telling whether a given file is encoded as normal or joint stereo, other than by listening (i.e. is there any tag info that would tell me?)

nick.

xen-uno · « **Reply #26 on:** April 04, 2004, 12:46:08 pm »

The numbered rates are not really presets, only -aps, -ape, -api are. To check out a particular file, select it and go to the Action Window. Dig into File Info>File Type Info (exact path unknown to me at this moment...on MJ). All that you ever wanted to know about the file is there.

R_x

nickharambee · « **Reply #27 on:** April 04, 2004, 12:47:02 pm »

ok, in contradiction to my previous post, i have just found this from the hydrogen audio webiste on recommended settings:

"note: --alt-preset cbr 320 is the exact same thing as --alt-preset insane"

so if they are exactly the same thing, how can one be normal stereo and the other joint stereo?

nick

nickharambee · « **Reply #28 on:** April 04, 2004, 12:57:12 pm »

ok, well, regardless of what hydrogen audio says, when i went into file type info, true enough the cbr alt preset insane did encode as 'joint stereo', whereas the 320 cbr setting encoded as 'stereo', so it looks like we have cleared this one up. it is now just down to my ears i suppose. as it happens i don't trust my ears that much after a few too many loud gigs, but i am trying to get the best quality files to use with pcdj for djing over my soundsystem (without using wav). is joint stereo generally recognised as better sound quality?

thanks for your help, nick.

xen-uno · « **Reply #29 on:** April 04, 2004, 01:25:42 pm »

> is joint stereo generally recognised as better sound quality

Nope...it's just another compression technique. The presets are not using JS exclusively. When warranted, Lame will throw true stereo frames in.

R_x

GHammer · « **Reply #30 on:** April 04, 2004, 09:41:50 pm »

Stereo vs Joint Stereo

Just a method of gaining additional bits to encode music info. In my listening, doesn't matter. So I allow the J.S. in order to let LAME have more room for audio info.

VBR vs CBR

Perhaps the reason your DJ software recommends CBR is that people have bed results with MP3s that lack a Xing header. If that header is missing then many apps do not know the duration, bitrate, etc and do poorly seeking within a file.

When I use LAME presets, I always get a Xing header. I've never had any MP3 tool complain.

Finally, if you really want to use an external encoder just to change the LAME version, you don't have to set up the external encoder entries. Just put the LAME.EXE you want into the Plugins directory.

nickharambee · « **Reply #31 on:** April 05, 2004, 01:27:43 am »

what is a xing header and where do i get one from??

nick

Alex B · « **Reply #32 on:** April 05, 2004, 04:37:59 am »

Quote from: nick_harambee on April 05, 2004, 01:27:43 am

what is a xing header and where do i get one from??

Xing Header is a type of VBR Header. VBR Header tells the player software how to play a VBR file. LAME makes Xing Header automatically when encoding VBR files, so you don't have to worry about it. In MC you can see if there is one in "File Type Info" e.g.:

MPEG-1 Layer 3
217 Kbit VBR (with Xing header)
44.1 Khz Joint stereo ...

I suggest that you make some testing with your DJ software. If a VBR file made with LAME works, then it works. Period.

One thing to consider is the encoding speed. CBR is much faster than VBR.

Some people who write to Hydrogenaudio forums have found that "--alt preset insane" setting is better than "--alt preset extreme" with certain music samples in some transient sounds. When I tried those I didn't hear the difference.

Once I tried "Mixmeister Pro" DJ software demo. It has a possibility to sync files by automatically making small adjustments to tempo in the end of the previous file and in the start of the next file. Maybe there is something like that in your DJ software and that might need CBR files.

If you have enough disc space for 320 kbit/s CBR, then go for it. If the music is full of stuff a VBR file can average about 250 kbit/s, so you don't save much space with VBR.

gpvillamil · « **Reply #33 on:** April 05, 2004, 08:09:00 am »

Quote from: nick_harambee on April 05, 2004, 01:27:43 am

what is a xing header and where do i get one from??

nick

Basically, with a constant bit rate MP3, your playback software can look at the file size and the bitrate and estimate how long it will take to play.

With VBR, if the software tries to estimate the playback time by looking at the bitrate, it will go up and down.

The Xing (named after a very old bad encoder) header basically contains information about the file size & contents, including duration and the number of frames that contain music data.

Some DJ programs need the Xing header in order to work properly. I believe MixMeister does not, since it does its own audio analysis on songs.

The LAME encoder (which is used by MC) makes an extended Xing header which should work with all modern MP3 players.

INTERACT FORUM

Author Topic: mp3s - vbr vs cbr? (Read 8992 times)

zevele10