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Is 320 CBR the best MP3 sound quality?
Hi people.

Apols if this has been asked umpteen times but I could not get a clear view on this.

OK VBR is the recommended standard.

But, I've seen comment that it sounds better than 320 CBR. Which I'm a bit confused about.

Ignoring file size aspects, surely 320 CBR would potentially be the best sound quality?

Cheers.

Is 320 CBR the best MP3 sound quality?
Reply #1
I think some encoders have had 384 kbps as an option but I don't know if that was outside of any ISO/offical specs. Others will be more of an help.

  • shadowking
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Is 320 CBR the best MP3 sound quality?
Reply #2
320 cbr is the highest 'mainstream' quality for mp3. You can have higher quality with freeformat upto 640k, but most decoders don't play it.
wavpack -b4x4s1c

Is 320 CBR the best MP3 sound quality?
Reply #3
"Sounds better" is a subjective term. VBR (variable bit rate) is better than CBR (constant bit rate) not because it "sounds better", but because it is more efficient.

Is 320 CBR the best MP3 sound quality?
Reply #4
Thanks for replies, yes I'm talking "mainstream".

I'm particularly interested in 320 CBR vs VBR V0.


Is 320 CBR the best MP3 sound quality?
Reply #5
"Sounds better" is a subjective term. VBR (variable bit rate) is better than CBR (constant bit rate) not because it "sounds better", but because it is more efficient.


Yes I fully concur that in terms of the file size/quality ratio, VBR is the place to be.

But ignoring file size, surely VBR could never sound better than 320 CBR. Assuming a version of LAME had been used that handled CBR well.

  • lvqcl
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  • Developer
Is 320 CBR the best MP3 sound quality?
Reply #6
Usually both CBR320 and V0 are transparent so they are equal in terms of sound quality.

There are tracks where CBR320 is better than V0.

But maybe there are also tracks where V0 is better than CBR320... LAME uses different compression algorithms for VBR and for CBR/ABR.

  • shadowking
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Is 320 CBR the best MP3 sound quality?
Reply #7
V0 should never be better than b320. If it is its some fluke. On some rare samples 320 or --abr 287 -h give better performance than V0

For the most defensive strategy that has mainstream playback ; -b320 or very high bitrate ABR is the way to go.
wavpack -b4x4s1c

  • psycho
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Is 320 CBR the best MP3 sound quality?
Reply #8
shadowking, so you're saying there are no problem samples, which affect CBR 320 kbps and don't affect VBR V0?
lame -V 0

  • birdie
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Is 320 CBR the best MP3 sound quality?
Reply #9
If your HDD/storage media permits, store and get all music in lossless format.

There's no excuse to compress audio nowadays.

  • [JAZ]
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Is 320 CBR the best MP3 sound quality?
Reply #10
We are mixing here theory and practice.


The teory is clear that CBR320 cannot be better than VBR, because VBR uses less, or at most the same amount of bits to encode the same thing.


In practice, they are different beasts, like in the use of the bit reservoir or the difference in the way the analisys is applied (search for best within bitrate constraint versus search for required amount within quality constraints).


Is 320 CBR the best MP3 sound quality?
Reply #11

We are mixing here theory and practice.


The teory is clear that CBR320 cannot be better than VBR, because VBR uses less, or at most the same amount of bits to encode the same thing.


That's what's confusing me. I always assumed that because VBR V0 varies the bitrate up to 320, whereas CBR 320 sticks slavishly to 320, VBR V0 cannot sound better then CBR 320. As good as perhaps, in so far as not to be able to notice the difference. But better? 


In practice, they are different beasts, like in the use of the bit reservoir or the difference in the way the analisys is applied (search for best within bitrate constraint versus search for required amount within quality constraints).


This is the interesting bit. Has LAME been so fine tuned to VBR that VBR V0 sounds better than CBR 320 even though VBR V0 uses less space (ergo is even more lossy)?
  • Last Edit: 13 February, 2010, 08:50:45 AM by TheGrimRipper

Is 320 CBR the best MP3 sound quality?
Reply #12
If your HDD/storage media permits, store and get all music in lossless format.

There's no excuse to compress audio nowadays.


MP3 is still more generically supported than FLAC for example. And in environments such as in the car, lossless vs lossy becomes a lot less noticeable especially at 320. And my alpine head unit doesn't decode FLAC. 

  • birdie
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Is 320 CBR the best MP3 sound quality?
Reply #13
Absolutely most people won't tell a difference between 192KBit MP3 and CD audio, so choose whatever you feel is right for you and for your requirements.

Theoretically 320CBR can have the same quality as --preset extreme (the best VBR quality) in lame.
  • Last Edit: 13 February, 2010, 08:55:53 AM by birdie

  • birdie
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Is 320 CBR the best MP3 sound quality?
Reply #14
If your HDD/storage media permits, store and get all music in lossless format.

There's no excuse to compress audio nowadays.


MP3 is still more generically supported than FLAC for example. And in environments such as in the car, lossless vs lossy becomes a lot less noticeable especially at 320. And my alpine head unit doesn't decode FLAC. 

Car audio is usually has so low quality, 192 VBR will be indistinguishable from CD audio - trust me.

Or don't trust me and go though a simple blind test - burn an audio CD with the same song burned say 10 times in audio CD quality and decompressed mp3 in random order.
  • Last Edit: 13 February, 2010, 09:00:45 AM by birdie

Is 320 CBR the best MP3 sound quality?
Reply #15
Or don't trust me and go though a simple blind test - burn an audio CD with the same song burned say 10 times in audio CD quality and decompressed mp3 in random order.


You are speaking to the converted here. 

The main reason for this thread is that someone who seems to talk knowledgeably said that VBR V0 blew CBR 320 away in terms of quality.

And I find that statement unbelievable.

So I thought I'd come back here to the font of all knowledge on such things and ask if things had radically changed in the few years since I last visited. 

  • trout
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Is 320 CBR the best MP3 sound quality?
Reply #16
God kills a kitten every time you encode with CBR 320.

</sarcasm>
~ Sorry for my bad english.

  • [JAZ]
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Is 320 CBR the best MP3 sound quality?
Reply #17

VBR may fail when it cannot see that it needs a higher bitrate than the one used, while CBR320 would be always using that bitrate (so innmune).
Then, there is also another thing related with the bit reservoir that can affect the distribution of bitrate in VBR, and as a consequence not have enough bitrate for a specific case*

CBR may fail in different cases. Even if it may seem ilogical, it may try to keep too much quality on some parts, and unexpectedly degrading others.

As said, VBR does not use the same procedures as CBR, and you can create a CBR file with the VBR algorithm (and with an attached VBR header) as was proposed once to research about a possible bug in CBR: http://www.hydrogenaudio.org/forums/index....st&p=583384



* say it decides it needs only a 32kbps frame, while the next doesn't have enough with a 320kbps one. If it had encoded the first one with 64kbps, it could have more space in the bit reservoir. Anyway, there are some limits that apply here too so I'm not sure how much of a difference can be in reality.


[Edit: removed first sentence. it didn't have sense]
  • Last Edit: 13 February, 2010, 09:11:33 AM by [JAZ]

Is 320 CBR the best MP3 sound quality?
Reply #18
Thanks, great link & very useful info.

I'm using LAME 3.97 at the moment for CBR, is it worth going to 3.98?

I'll likely give VBR a go to and do some blind testing. Is 3.98 the release to go with for VBR?
  • Last Edit: 29 July, 2011, 07:57:13 AM by db1989

  • halb27
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Is 320 CBR the best MP3 sound quality?
Reply #19
Yes, it's worth going to 3.98, especially when using VBR.

3.97 had inadequate problems with a certain kind of distortion called 'sandpaper noise problem' as well as with a certain trumpet sample. Moreover AFAIK there was tuning with 3.98 towards the more usual pre-echo problems.
So the quality of 3.98 is more homogeneously good than that of 3.97. This is more important when using VBR than when using ABR/CBR, as the VBR quality relies more heavily on the quality of the psy model and its implementation.

lame3995o -Q1

  • /mnt
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Is 320 CBR the best MP3 sound quality?
Reply #20
I do have track that does sound worse with 320kbps then V0.

320kbps vs FLAC
Code: [Select]
foo_abx 1.3.4 report
foobar2000 v1.0
2010/02/13 14:55:54

File A: J:\Music\Lossless\Kraftwerk - The Man Machine\03. Metropolis.flac
File B: C:\Temp\Metropolis 320 CBR.mp3

14:55:54 : Test started.
14:56:26 : 01/01  50.0%
14:56:30 : 02/02  25.0%
14:56:34 : 03/03  12.5%
14:56:38 : 04/04  6.3%
14:56:42 : 05/05  3.1%
14:56:46 : 06/06  1.6%
14:56:49 : 07/07  0.8%
14:56:53 : 08/08  0.4%
14:56:57 : 09/09  0.2%
14:57:02 : 10/10  0.1%
14:57:07 : 11/11  0.0%
14:57:12 : 12/12  0.0%
14:57:17 : 13/13  0.0%
14:57:21 : 14/14  0.0%
14:57:25 : 15/15  0.0%
14:57:26 : Test finished.

 ----------
Total: 15/15 (0.0%)
Pre-echo throughout the start, but it's not annoying. Sadly at 0:09 there is a very obivous and annoying precho artifact.

320kbps vs V0
Code: [Select]
foo_abx 1.3.4 report
foobar2000 v1.0
2010/02/13 15:00:10

File A: C:\Temp\Metropolis 320 CBR.mp3
File B: C:\Temp\Metropolis V0.mp3

15:00:10 : Test started.
15:00:39 : 01/01  50.0%
15:00:42 : 02/02  25.0%
15:00:48 : 03/03  12.5%
15:00:52 : 04/04  6.3%
15:00:55 : 05/05  3.1%
15:01:02 : 06/06  1.6%
15:01:07 : 07/07  0.8%
15:01:10 : 08/08  0.4%
15:01:14 : 09/09  0.2%
15:01:19 : 10/10  0.1%
15:01:24 : 11/11  0.0%
15:01:30 : 12/12  0.0%
15:01:34 : 13/13  0.0%
15:01:38 : 14/14  0.0%
15:01:42 : 15/15  0.0%
15:01:45 : 16/16  0.0%
15:01:46 : Test finished.

 ----------
Total: 16/16 (0.0%)

At the start V0 does produce slightly rougher precho, but at 0:09 the 320kbps file stands out greatly. While the 0:09 mark on the V0 file lacks the annoying artifact.

I'm using LAME 3.97 at the moment for CBR, is it worth going to 3.98?

If you are already using 320kbps CBR on LAME 3.97 with no compat issues i would stick with it. Since LAME 3.98 has some regression issues with problem tracks, due to it using a smaller frame size to make it 100% ISO compliant.
  • Last Edit: 13 February, 2010, 10:31:21 AM by /mnt
"I never thought I'd see this much candy in one mission!"

  • lvqcl
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  • Developer
Is 320 CBR the best MP3 sound quality?
Reply #21
So we have two opinions:

3.98 is better than 3.97:
3.97 had inadequate problems with a certain kind of distortion called 'sandpaper noise problem' as well as with a certain trumpet sample.

3.97 is better than 3.98:
If you are already using 320kbps CBR on LAME 3.97 with no compat issues i would stick with it. Since LAME 3.98 has some regression issues with problem tracks


  • Soap
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Is 320 CBR the best MP3 sound quality?
Reply #22
I was under the impression the sandpaper noise issue was only in regards to VBR, is this correct?
Regardless, both statements are factually correct, as both are real issues not present in the other.
  • Last Edit: 29 July, 2011, 07:57:31 AM by db1989
Creature of habit.

  • timcupery
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Is 320 CBR the best MP3 sound quality?
Reply #23
The reason that 3.98 regresses compared to 3.97, with some problem tracks, is because the Lame devs changed the handling of the bit reservoir. Basically, some outdated decoders had trouble with 320kbps frames that used too much bit reservoir from previous frames. Unfortunately, one such outdated decoder was in WMP, which is used by many people. I haven't been able to replicate this problem with WMP 11 or 12 (on XP and Win7, respectively), but I understand the Lame devs' goal that Lame mp3's play on anything that handles mp3.

So basically, 3.98 can't go as high of a bitrate in a single frame, as 3.97, and thus will struggle with a few problem samples.

As I understand it, the actual spec definition of mp3-format's bit reservoir is somewhat vague, so Lame 3.97 and prior could be read as spec-compliant, but so could the problematic WMP decoder.

But the tuning changes between 3.97 and 3.98 have still improved 3.98 for other issues.
God kills a kitten every time you encode with CBR 320

  • lvqcl
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  • Developer
Is 320 CBR the best MP3 sound quality?
Reply #24
Quote
I haven't been able to replicate this problem with WMP 11 or 12 (on XP and Win7, respectively)

Try mplayer2.exe