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Topic: RazorLame (Read 4939 times) previous topic - next topic
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RazorLame

I'm not sure I have this VBR thing right so please help.

I have encoded a 10 minute 109 Meg wav file various mp3 bit rates using the following instructions and receiving the following outputs according to Windows Explorer


1. -b 320 -m j --lowpass 19.5 -q 2 This would be CBR 320 right?
I got 25 megs at 320 kps......so far so good

2. -b 320 -m j -V 1 -B 192 --lowpass 19.5 -q 2 This would be CBR 320 Variable 192 right? I got 25 megs at 320 kps.......hmmm

3. -b 192 -m j --lowpass 19.5 -q 2 This would be CBR 192 right? I got 15 megs at 192 kps......OK

4. -b 192 -m j -V 1 -B 192 --lowpass 19.5 -q 2 This would be CBR 192 Variable 192 right? I got 15 megs at 476 kbs.......whoa!

5. -b 192 -m j -V 1 -B 320 --lowpass 19.5 -q 2 This would be CBR 192 Variable 320 right? I got 15 megs at 476 kps..... the same? what?

6. -b 320 -m j -V 1 -B 320 --lowpass 19.5 -q 2 This would be CBR 320 Variable 320 right? I got 25 megs at 320 kps........a larger file with a lower kbs!!!!!!!

I don't get it. kbs indicates quality doesn't it?

To make matters worse I used a preset --R3Mix for VBR archival and got an 8.5 meg file at 232 kps but its doesn't spell out the parameters.  Now this looks like a pretty good compromise,but what about the size vs kps differences?

Steve Cat (newbie)

RazorLame

Reply #1 –
Quote
1. -b 320 -m j --lowpass 19.5 -q 2 This would be CBR 320 right?
I got 25 megs at 320 kps......so far so good


Yup, for 320kbit/s CBR files you should use the command line --alt-preset insane (for best results use version 3.90.3), though.  You won't be able to come up with a command line of your own to best that.

Quote
2. -b 320 -m j -V 1 -B 192 --lowpass 19.5 -q 2 This would be CBR 320 Variable 192 right? I got 25 megs at 320 kps.......hmmm


-b = minimum bitrate
-B = maximum bitrate

In this case -b setting overrides -B setting (because you set -b first).  Thus the file became another CBR 320 file because -b 320 didn't allow LAME to encode any frames lower than that.  Note:  NEVER use anything other than -B 320 because even at CBR 128 some frames go up to 320kbit/s due to bit resevoir.

Quote
3. -b 192 -m j --lowpass 19.5 -q 2 This would be CBR 192 right? I got 15 megs at 192 kps......OK


Yup, thats right.  For CBR 192 files the command line --alt-preset CBR 192 will give you the best results.  --alt-preset 192 will give you an ABR file which should sound slightly better than the CBR file.

Quote
4. -b 192 -m j -V 1 -B 192 --lowpass 19.5 -q 2 This would be CBR 192 Variable 192 right? I got 15 megs at 476 kbs.......whoa!


I don't know where you got the idea that this file is 476kbit/s.  If it was it would have to be bigger than the 320kbit/s files you made, yet it is smaller.  This is because this file is actually CBR 192.  How do I know this?

-b 192
-B 192

This tells the encoder that no frame may be bigger or smaller than 192, thus all frames are 192kbit/s.

Quote
5. -b 192 -m j -V 1 -B 320 --lowpass 19.5 -q 2 This would be CBR 192 Variable 320 right? I got 15 megs at 476 kps..... the same? what?


This is also CBR 192.

Quote
6. -b 320 -m j -V 1 -B 320 --lowpass 19.5 -q 2 This would be CBR 320 Variable 320 right? I got 25 megs at 320 kps........a larger file with a lower kbs!!!!!!!


This is another CBR 320 file.

For the best results with VBR use --alt-preset standard ~200kbit/s or --alt-preset extreme ~225kbit/s.  I recommend --alt-preset standard as it is smaller and you shouldn't be able to tell the difference on most samples.
gentoo ~amd64 + layman | ncmpcpp/mpd | wavpack + vorbis + lame

RazorLame

Reply #2 –
>I don't know where you got the idea that this file is 476kbit/s. If it was it would have to be bigger than the 320kbit/s files you made, yet it is smaller. This is because this file is actually CBR 192. How do I know this?

-b 192
-B 192


Don't know how to use the quote funtion either!

Anyway in Windows Explorer if you move the mouse over the file name it tells you the kps.  It correctly points out the CBR encodes @ 192 and 320. This oddity is what caused my question.  Does it have something to do with the V -1 quality setting being constant?  or maybe this is a bug in version 3.95.1

Should I be using 3.90.3 instead?

Steve Cat

RazorLame

Reply #3 –
Windows is not the best at picking out average bitrates on VBR files...

Perhaps this thread would help Read Me
"You can fight without ever winning, but never win without a fight."  Neil Peart  'Resist'

RazorLame

Reply #4 –
Quote
Anyway in Windows Explorer if you move the mouse over the file name it tells you the kps.  It correctly points out the CBR encodes @ 192 and 320. This oddity is what caused my question.  Does it have something to do with the V -1 quality setting being constant?  or maybe this is a bug in version 3.95.1

This is a bug in the way Window's reports VBR:

More information here.
daefeatures.co.uk

RazorLame

Reply #6 –
Quote
Are they too lazy to implement Xing/VBRI header support?

Apparently so! Relying on ID3v2 "TLEN" is just... weird? bad? lazy? microsoft? And they even link to the wrong ID3v2 site...

RazorLame

Reply #7 –
Hmm, as I use WMP and id3v2 myself, would it be possible to write a utility to do this? I mean it seems fairly straight-forward just to copy the field from the XING header into an id3v2 frame. Unfortunately I'm a pretty crappy programmer

EDIT: Or just make LAME XP-compatible by adding a -tlen switch at encode-time?

RazorLame

Reply #8 –
Thanks to all who posted.  I installed  3.90.3 and used the --altextreme preset and am very pleased with the results from a quality and size standpoint.  Using the Winamp info funtion correctly identified kps.

Thanks
Steve Cat

RazorLame

Reply #9 –
Just out of curiosity why does it say warn 0% and the bar graph on my profile on the left?
 

RazorLame

Reply #10 –
Quote
Just out of curiosity why does it say warn 0% and the bar graph on my profile on the left?

That is only visible to you. It tells you that you have not got a warning yet...