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-V2 gives way too high bitrate!?!
masterridley
post Mar 29 2010, 16:48
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I use dbpoweramp and I encode flac tracks to LAME 3.98r -V2. Usually this results in ~170 to ~220 kbps files (close to 192kbps CBR quality)

Well, not so for 2 As I Lay Dying albums that I have (think REALLY LOUD metal). When I encode those I get 230-270 kbps and of course the resulting files are quite big.

My question is: is this a bug or completely natural?
Furthermore (if it's not a bug), isn't it just better to encode in 192kbps and get a smaller file, since that's the quality I was going for anyway?

Cheers
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robert
post Apr 1 2010, 11:37
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QUOTE
If global gain is zero, resolution will need to be increased (and quantization lowered) on every other scale factor band.

The sentence from the wiki makes no sense. Though the corresponding section at mp3-tech.org does explain the sfb21 problematic very well.

QUOTE
Scale factor refers to how much quantization (loss of precision) is applied to each band, where higher quantization causes greater compression, and consequently less variation between the minimum and maximum values (resolution).

- scale factors allow to reduce the quantization step size per sfb, within a limited range, as a deviation from the global step size (global gain).
- quantization is a process. larger quantization step sizes allow greater compression, this results in more quantization noise.

QUOTE
Global gain is an extra quantizer that affects all bands simultaneously.

This is plain wrong.

QUOTE
The only way to increase the resolution on sfb21 is therefore to reduce the global gain quantization, since global gain applies to all bands.

Needs correction.

QUOTE
If global gain is zero, resolution will need to be increased (and quantization lowered) on every other scale factor band.

If global gain is zero, then there is nothing you can do anymore.

QUOTE
LAME implements the -Y switch as a way to activate the alternate logic that CBR uses in respect to quantization noise in the sfb21 band.

No, it's an off switch. It turns off code that's used in higher quality VBR settings.

QUOTE
Since the sfb21 does not have quantization, its quantization noise is not evaluated.

Makes no sense. The content of sfb21 will surely get quantized.

QUOTE
In MPEG2 (16,22,24Khz), it is sfb12.

This is wrong. Long blocks have 22 sfbs (sfb0 - sfb21), short blocks have 13 sfbs (sfb0-12). The short block sfb12 has no scale factor of its own, like the long block sfb21.

This post has been edited by robert: Apr 1 2010, 13:44
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Posts in this topic
- masterridley   -V2 gives way too high bitrate!?!   Mar 29 2010, 16:48
- - dv1989   Natural. VBR targets quality, not bitrate. Loud me...   Mar 29 2010, 16:52
|- - dsimcha   QUOTE (dv1989 @ Mar 29 2010, 11:52) Natur...   Mar 29 2010, 16:56
- - [JAZ]   metal (being loud and "noisy"*) kicks on...   Mar 29 2010, 17:06
- - masterridley   Damn! That's what I suspected too (compres...   Mar 29 2010, 17:07
- - robert   You could update to LAME 3.98.4, as previous 3.98 ...   Mar 29 2010, 17:13
- - pdq   QUOTE (masterridley @ Mar 29 2010, 11:48)...   Mar 29 2010, 17:14
- - dv1989   QUOTE (pdq)If you really want the best quality whi...   Mar 29 2010, 17:24
- - masterridley   QUOTE (JAZ)Two ways to workaround (workaround not ...   Mar 29 2010, 17:26
- - greynol   -Y does not cut content above 16k; it is not a low...   Mar 29 2010, 17:43
- - lvqcl   QUOTE Regarding -Y, doesn't it kick in with -V...   Mar 29 2010, 18:06
- - Aleron Ives   I hate to continue discussion about -Y since it se...   Mar 30 2010, 04:59
|- - greynol   QUOTE (Aleron Ives @ Mar 29 2010, 20:59) ...   Mar 30 2010, 05:20
|- - Aleron Ives   QUOTE (greynol @ Mar 29 2010, 20:20) QUOT...   Mar 30 2010, 05:48
- - shadowking   I suggest not to fiddle with -Y . If you want a lo...   Mar 30 2010, 11:10
|- - Aleron Ives   QUOTE (shadowking @ Mar 30 2010, 02:10) I...   Mar 30 2010, 23:38
- - [JAZ]   I am preparing to put this on the wiki (but my use...   Mar 30 2010, 12:03
- - benski   very short version: -Y switch makes LAME not encod...   Mar 30 2010, 17:35
- - greynol   It was not too long and is well worth reading, ben...   Mar 30 2010, 17:42
|- - benski   QUOTE (greynol @ Mar 30 2010, 11:42) It w...   Mar 30 2010, 17:44
- - greynol   I hope you caught my edits above since I think you...   Mar 30 2010, 17:55
- - [JAZ]   I would like an answer from robert, or someone tha...   Mar 31 2010, 10:25
|- - Aleron Ives   QUOTE ([JAZ] @ Mar 31 2010, 02:25...   Mar 31 2010, 10:53
|- - robert   QUOTE ([JAZ] @ Mar 31 2010, 11:25...   Mar 31 2010, 12:33
- - shadowking   -Y is still 'experimental'. It was never ...   Mar 31 2010, 11:52
|- - Aleron Ives   I would like to thank robert for explaining the co...   Mar 31 2010, 23:58
- - [JAZ]   Thanks robert. I've used your explanations as ...   Mar 31 2010, 13:16
- - Ajax   The original poster "masterridley" (a ne...   Mar 31 2010, 14:16
- - robert   global gain: is the global quantization step size ...   Mar 31 2010, 14:25
- - pdq   @[JAZ] You might also point out that for older fo...   Mar 31 2010, 14:47
- - shadowking   We should not be recommending or documenting -Y un...   Mar 31 2010, 14:53
- - dv1989   QUOTE (Knowledgebase)LAME Y SWITH Surely I needn...   Mar 31 2010, 15:04
- - [JAZ]   DOH! I saw something strange in that, but i d...   Mar 31 2010, 20:45
- - dv1989   The spelling was one thing. Also, it may not matte...   Mar 31 2010, 21:09
- - shadowking   This is still going back to my point. Users don...   Apr 1 2010, 10:49
|- - Aleron Ives   QUOTE (shadowking @ Apr 1 2010, 02:49) Th...   Apr 1 2010, 11:18
|- - greynol   QUOTE (shadowking @ Apr 1 2010, 02:49) Us...   Apr 1 2010, 18:28
- - [JAZ]   Robert, can you comment on this line of the articl...   Apr 1 2010, 11:22
- - robert   QUOTE If global gain is zero, resolution will need...   Apr 1 2010, 11:37
- - [JAZ]   Talk about failing to read... I didn't ful...   Apr 1 2010, 13:39


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