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  • VBRecon
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LAME -V0 - is it constrained to hit 245 kbps avg?
Hello everyone.  I'm trying to understand if the LAME -V0 preset is constrained in the amount of bitrate it can use.

For instance, if it was tasked with compressing some hypothetical "most challenging audio track ever", is it capable of ramping up the bitrate to 320 kbps and holding that for the duration of the track if it was deemed necessary to achieve the maximum quality?

Another way to put it... Is the -V0 preset a choice for maximum constant quality with bitrate and file size being unconstrained?  Or is it a choice for maximum quality within a bitrate range that averages around 245 kbps?  I'm guessing it's the former but I haven't been able to find a clear statement to that effect.

I ask because the encodings I do with that preset vary in bitrate allocation, but they always cluster around 224/256 (as shown in the command line window graph).  Which led me to question whether it was constrained or if that's all the bitrate that LAME needs to achieve optimum results.

Thanks.


  • saratoga
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #1
Its not constrained, that would be ABR.

VBR in lame picks whatever bitrate it needs to hit a given quality level.

  • VBRecon
  • [*]
LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #2
Its not constrained, that would be ABR.

VBR in lame picks whatever bitrate it needs to hit a given quality level.

So in LAME's current state the -V0 preset achieves the maximum quality the encoder is capable of, while using no more bitrate than necessary to achieve it?  In theory a more efficient equivalent to the -b 320 preset?  Generally speaking that is.  I wouldn't expect the differing approaches to result in truly identical files, I'm just trying to a get a better grip on how these 2 presets compare.

  • saratoga
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #3
Its not constrained, that would be ABR.

VBR in lame picks whatever bitrate it needs to hit a given quality level.

So in LAME's current state the -V0 preset achieves the maximum quality the encoder is capable of, while using no more bitrate than necessary to achieve it?  In theory a more efficient equivalent to the -b 320 preset?  Generally speaking that is.  I wouldn't expect the differing approaches to result in truly identical files, I'm just trying to a get a better grip on how these 2 presets compare.


In 320 CBR, all frames are 320, and any excess space is simply padded with zeros.  In -V0, rather than zero padding, the frame size is reduced if the encoder judges that there are excess bits available.

  • mjb2006
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #4
VBR: consistent quality, variable bitrate.
CBR: variable quality, consistent bitrate.
Bitrate for maximum quality = the minimum bitrate that achieves transparency, for that audio, for you—or any higher bitrate; once transparency is achieved, they're all the same, unless something's wrong with the encoder.

If you worry that V0 isn't good enough for you, you can try 320 CBR, but don't say it's higher quality without posting ABX test results showing you can hear a difference. (I don't think anyone ever has, to date.) It would be better to just switch to lossless if you want to eradicate the risk, however slight, of ever hearing a difference.
  • Last Edit: 12 January, 2014, 07:34:01 PM by mjb2006

  • VBRecon
  • [*]
LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #5
In 320 CBR, all frames are 320, and any excess space is simply padded with zeros.  In -V0, rather than zero padding, the frame size is reduced if the encoder judges that there are excess bits available.

That's very interesting.  So the data content is the same, it's just the padding/bitrate format that differs.


VBR: consistent quality, variable bitrate.
CBR: variable quality, consistent bitrate.
Bitrate for maximum quality = the minimum bitrate that achieves transparency, for that audio, for you—or any higher bitrate; once transparency is achieved, they're all the same, unless something's wrong with the encoder.

If you worry that V0 isn't good enough for you, you can try 320 CBR, but don't say it's higher quality without posting ABX test results showing you can hear a difference. (I don't think anyone ever has, to date.) It would be better to just switch to lossless if you want to eradicate the risk, however slight, of ever hearing a difference.

As I suspected the VBR mode could alternately be referred to as Constant Quality, with -V0 being the best LAME is capable of.

I understand about the transparency threshold, but for me it's been something of a moving target as it varies by playback equipment and environment.  My equpment seem to be improving over time so I want to consider that when choosing an encoding technique.  Knowing what I learned today I see no benefit in choosing 320 CBR over -V0 VBR for my current and near-future playback needs.  By extension lossless encoding would also be of no value, but it would certainly be my choice if the goal was to preserve original source media in a digital/backup format.

  • saratoga
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #6
In 320 CBR, all frames are 320, and any excess space is simply padded with zeros.  In -V0, rather than zero padding, the frame size is reduced if the encoder judges that there are excess bits available.

That's very interesting.  So the data content is the same, it's just the padding/bitrate format that differs.


Its not necessarily the same data. 

I understand about the transparency threshold, but for me it's been something of a moving target as it varies by playback equipment and environment.


The best you can do for spotting compression artifacts is a typical pair of headphones, so I wouldn't worry about that. 

  • VBRecon
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #7
Its not necessarily the same data.

OK, so like I said earlier, the differing approaches will not result in truly identical results.  Which would support the LAME "recommended switches" help page comment on 320 CBR: "With the exception of a few situations, quality is rarely better than the highest VBR profiles..."

Well that doesn't change the conclusion I reached in my last post, of 320 not offering a benefit over -V0 for my daily needs.  Thank you both for helping get rid of that nagging doubt I had each time I'd compress something.
  • Last Edit: 12 January, 2014, 11:41:43 PM by VBRecon

  • Kohlrabi
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  • Global Moderator
LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #8
FWIW, even -V0 is far above my transparency threshold, so -V0 might also be total overkill for you. Don't fear to test that.
  • Last Edit: 13 January, 2014, 01:26:41 AM by Kohlrabi
It's only audiophile if it's inconvenient.

  • ash92
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #9




My songs. At many bitrates

LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #10
@ash92 Your point being...?
  • Last Edit: 13 January, 2014, 04:39:01 AM by includemeout
Listen to the music, not the media.

Best,
Nilson

  • ash92
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #11
I think VBR is not limited and if the song is complex enough can reach a higher bitrate. In the picture above I have given an example of complex music.
I apologize for the inaccuracy use translator.

LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #12
Yeah, but from what you could gather, don't you think the previous posts had already made that quite clear?
Listen to the music, not the media.

Best,
Nilson

  • ash92
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #13
Sorry

  • TomasPin
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #14
FWIW, even -V0 is far above my transparency threshold

I'd say it's far above most mortals' transparency thresholds... I pity those for whom it's "not enough" (whether they are certain of it, or not and just wasting space).

Anyway, I think the OP was given a satisfactory answer.
  • Last Edit: 13 January, 2014, 10:40:00 AM by TomasPin
A man and his music: http://tubular.net/

  • naturfreak
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #15
A wild guess: I get MP3 files with that kind of bitrate distribution when I encode music to 320 kbps and run them through mp3packer afterwards. Then most of the mp3 files are in the range of 290 to 315 kbps.

  • JJZolx
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LAME -V0 - is it constrained to hit 245 kbps avg?
Reply #16
I understand about the transparency threshold, but for me it's been something of a moving target as it varies by playback equipment and environment.  My equpment seem to be improving over time so I want to consider that when choosing an encoding technique.  Knowing what I learned today I see no benefit in choosing 320 CBR over -V0 VBR for my current and near-future playback needs.  By extension lossless encoding would also be of no value, but it would certainly be my choice if the goal was to preserve original source media in a digital/backup format.


Why not just go lossless and be done with it? Hard disk space is so cheap today that unless you're ripping and encoding tens of thousands of CDs, the difference between using Mp3 and FLAC is going to be a few dollars worth of drive space.