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Informed rebuttal of VBR disadvantages appreciated, VBR always rocks, when it comes to lossy compression, right?
Moon
post Oct 16 2008, 09:54
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As already mentinend in this thread some fanboy over at the offical Pioneer forums is making claims that VBR sucks (here and here) in that it needs more processing power compared to CBR and for various other reasons.

I would like to have a well written rebuttal of that statment based on facts so Pioneer might reconsider putting VBR support into their upcoming DJ equipment. I've ripped all my 1000+ CDs to VBR and I wouldn't want to reencode them just because Pioneer doesn't get it right. Thanks!
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xmixahlx
post Oct 17 2008, 05:52
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1. regarding the difficulty of decoding VBR

it's hard to believe the supposed difficulty of implementing a proper mp3 decoder when an open source project (rockbox: http://rockbox.org/ ) has full support for several (and some much more hardware demanding) codecs.

old 140mhz coldfire processors are decoding ALL proper mp3 streams at about 5x - 4x realtime.

as implemented in rockbox, the mp3 decoder does not vary according to encoding strategy much, but it DOES vary significantly in regards to filesize. so the OPPOSITE argument could be made, that it is easier and faster to decode a VBR file averaging 190kbps (i.e. -V2) then it is to decode a 320kbps CBR file.

for rockbox this is generally true for most target architectures (and for all codecs other than some lossless implementations like monkey's audio and wavpack which take a decoding hit with more complicated encoding settings.)

data can be found on the rockbox site to support these claims here:
http://www.rockbox.org/twiki/bin/view/Main/IriverRuntime
http://www.rockbox.org/twiki/bin/view/Main...manceComparison

this can also be verified through lame. both encoding and decoding takes longer with CBR 320 files then it does via -V0 VBR files.

VBR encoding
CODE
mike@xmixahlx:~$ time lame -V6 --silent --noreplaygain 41_30sec.wav 41_30sec-V6.mp3

real    0m1.222s
user    0m1.216s
sys     0m0.004s
mike@xmixahlx:~$ time lame -V5 --silent --noreplaygain 41_30sec.wav 41_30sec-V5.mp3

real    0m1.298s
user    0m1.276s
sys     0m0.016s
mike@xmixahlx:~$ time lame -V4 --silent --noreplaygain 41_30sec.wav 41_30sec-V4.mp3

real    0m1.313s
user    0m1.284s
sys     0m0.016s
mike@xmixahlx:~$ time lame -V3 --silent --noreplaygain 41_30sec.wav 41_30sec-V3.mp3

real    0m1.342s
user    0m1.328s
sys     0m0.016s
mike@xmixahlx:~$ time lame -V2 --silent --noreplaygain 41_30sec.wav 41_30sec-V2.mp3

real    0m1.409s
user    0m1.400s
sys     0m0.008s
mike@xmixahlx:~$ time lame -V1 --silent --noreplaygain 41_30sec.wav 41_30sec-V1.mp3

real    0m1.580s
user    0m1.408s
sys     0m0.016s
mike@xmixahlx:~$ time lame -V0 --silent --noreplaygain 41_30sec.wav 41_30sec-V0.mp3

real    0m1.482s
user    0m1.448s
sys     0m0.024s


CBR encoding
CODE
mike@xmixahlx:~$ time lame -b 128 --silent --noreplaygain 41_30sec.wav 41_30sec-128.mp3

real    0m2.064s
user    0m2.052s
sys     0m0.016s
mike@xmixahlx:~$ time lame -b 160 --silent --noreplaygain 41_30sec.wav 41_30sec-160.mp3

real    0m2.154s
user    0m2.120s
sys     0m0.032s
mike@xmixahlx:~$ time lame -b 192 --silent --noreplaygain 41_30sec.wav 41_30sec-192.mp3

real    0m1.770s
user    0m1.768s
sys     0m0.000s
mike@xmixahlx:~$ time lame -b 224 --silent --noreplaygain 41_30sec.wav 41_30sec-224.mp3

real    0m1.807s
user    0m1.768s
sys     0m0.012s
mike@xmixahlx:~$ time lame -b 256 --silent --noreplaygain 41_30sec.wav 41_30sec-256.mp3

real    0m1.779s
user    0m1.752s
sys     0m0.028s
mike@xmixahlx:~$ time lame -b 320 --silent --noreplaygain 41_30sec.wav 41_30sec-320.mp3

real    0m1.686s
user    0m1.676s
sys     0m0.008s


VBR decoding
CODE
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V6.mp3

real    0m0.271s
user    0m0.252s
sys     0m0.008s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V5.mp3

real    0m0.273s
user    0m0.256s
sys     0m0.004s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V4.mp3

real    0m0.270s
user    0m0.248s
sys     0m0.020s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V3.mp3

real    0m0.272s
user    0m0.256s
sys     0m0.016s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V2.mp3

real    0m0.289s
user    0m0.272s
sys     0m0.020s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V1.mp3

real    0m0.289s
user    0m0.276s
sys     0m0.008s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-V0.mp3

real    0m0.293s
user    0m0.272s
sys     0m0.020s



CBR decoding
CODE
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-128.mp3

real    0m0.256s
user    0m0.240s
sys     0m0.016s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-160.mp3

real    0m0.267s
user    0m0.256s
sys     0m0.012s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-192.mp3

real    0m0.274s
user    0m0.264s
sys     0m0.008s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-224.mp3

real    0m0.285s
user    0m0.256s
sys     0m0.028s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-256.mp3

real    0m0.291s
user    0m0.280s
sys     0m0.008s
mike@xmixahlx:~$ time lame --silent --decode 41_30sec-320.mp3

real    0m0.306s
user    0m0.296s
sys     0m0.008s


2. regarding VBR being an inferior encoding strategy to CBR

in current years (i.e. >2000 e.g. 3.90beta, since --dm-presets/--alt-presets/--presets) with lame the opposite has proved true except for specific problem samples.


later

This post has been edited by xmixahlx: Oct 17 2008, 05:59


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Posts in this topic
- Moon   Informed rebuttal of VBR disadvantages appreciated   Oct 16 2008, 09:54
- - Raiden   Don't waste your energy. Self-absorbed people ...   Oct 16 2008, 10:51
- - halb27   It's all up to whether an encoder works well. ...   Oct 16 2008, 11:27
- - JensRex   Yes, don't waste your time. That guy is comple...   Oct 16 2008, 11:43
- - Slipstreem   As the other guys have already said, you're wa...   Oct 16 2008, 12:56
|- - add   QUOTE (Slipstreem @ Oct 16 2008, 13:56) C...   Oct 16 2008, 16:40
|- - Lyx   QUOTE (add @ Oct 16 2008, 17:40) QUOTE (S...   Oct 16 2008, 17:19
- - probedb   No point with some of these people....I've giv...   Oct 16 2008, 12:59
- - Canar   These threads are really old. I created an account...   Oct 16 2008, 16:59
|- - Synthetic Soul   QUOTE (Canar @ Oct 16 2008, 16:59) I resp...   Oct 16 2008, 17:08
- - Canar   No, I think I'm going mad. That post I made is...   Oct 16 2008, 18:10
|- - uart   QUOTE (Canar @ Oct 16 2008, 09:10) No, I ...   Oct 16 2008, 20:01
- - Slipstreem   Well, we have an answer of sorts over there from a...   Oct 16 2008, 18:18
- - Soap   Mind, if you do decide to argue: The argument that...   Oct 16 2008, 18:59
- - Slipstreem   I'm specifically not joining that forum as I...   Oct 16 2008, 19:39
- - Canar   Who is BDX?   Oct 16 2008, 20:03
|- - DJRyanJ   Alright guys, I'm the guy who did the wall of ...   Oct 16 2008, 20:49
|- - halb27   QUOTE (DJRyanJ @ Oct 16 2008, 21:49) ...S...   Oct 16 2008, 21:29
|- - kwanbis   QUOTE (DJRyanJ @ Oct 16 2008, 19:49) 5) W...   Oct 16 2008, 21:36
- - uart   I dont know, it's not me. Does anyone have a t...   Oct 16 2008, 20:06
- - Slipstreem   It wasn't me either, and I don't have a tr...   Oct 16 2008, 20:12
- - kornchild2002   I will post just to be ballsy. I don't see Pu...   Oct 16 2008, 20:48
- - Canar   I don't have the time right now to get more in...   Oct 16 2008, 21:13
- - m0rbidini   Pioneer should support VBR and stfu. If using VBR ...   Oct 16 2008, 21:57
- - DJRyanJ   OK, I have a brief moment here before my midterm s...   Oct 16 2008, 22:00
|- - Ron Jones   QUOTE (DJRyanJ @ Oct 16 2008, 14:00) Why ...   Oct 16 2008, 22:59
|- - m0rbidini   QUOTE (DJRyanJ @ Oct 16 2008, 22:00) QUOT...   Oct 16 2008, 23:32
|- - kwanbis   QUOTE (DJRyanJ @ Oct 16 2008, 21:00) I...   Oct 17 2008, 03:09
- - [JAZ]   I guess most it said already but I'd like to c...   Oct 16 2008, 23:01
- - Axon   What MP3 decoding library does Wavelab use? It...   Oct 16 2008, 23:02
- - DJRyanJ   QUOTE About 0.01% had issues. Most where CBRs. Di...   Oct 17 2008, 04:39
|- - kwanbis   QUOTE (DJRyanJ @ Oct 17 2008, 03:39) Did ...   Oct 17 2008, 05:06
- - xmixahlx   1. regarding the difficulty of decoding VBR it...   Oct 17 2008, 05:52
- - m0rbidini   QUOTE I've seen this in my very limited video ...   Oct 17 2008, 11:00
- - Lyx   Why have a long discussion when it all can be summ...   Oct 17 2008, 13:21
|- - halb27   QUOTE (Lyx @ Oct 17 2008, 14:21) Why have...   Oct 17 2008, 14:33
|- - lvqcl   QUOTE (halb27 @ Oct 17 2008, 17:33) QUOTE...   Oct 17 2008, 14:49
|- - Lyx   QUOTE But maximum bitrate for LAME VBR (i.e. lame ...   Oct 17 2008, 15:13
- - pdq   I am guessing (and I don't really know anythin...   Oct 17 2008, 13:50
- - Slipstreem   Won't the part of the audio stream being worke...   Oct 17 2008, 13:57
|- - pdq   QUOTE (Slipstreem @ Oct 17 2008, 08:57) W...   Oct 17 2008, 14:48
- - Synthetic Soul   DJRyanJ, kudos for making the effort to partake in...   Oct 17 2008, 14:04
- - Slipstreem   I'm gonna have to go and read more about how t...   Oct 17 2008, 15:01
- - Slipstreem   The only problem I can see with that is that some ...   Oct 17 2008, 15:43
|- - Lyx   QUOTE (Slipstreem @ Oct 17 2008, 16:43) T...   Oct 17 2008, 15:56
- - halb27   IMO the old --preset scheme or a similar one addre...   Oct 17 2008, 15:59
- - greynol   Now we're just going around in circles. There...   Oct 17 2008, 16:05
|- - Lyx   QUOTE (greynol @ Oct 17 2008, 17:05) Now ...   Oct 17 2008, 16:21
- - Synthetic Soul   We're also going way off-topic...   Oct 17 2008, 16:53
- - Slipstreem   A quick heads-up (not that I've been spying). ...   Oct 17 2008, 19:25
- - DJRyanJ   I actually know Pulse personally and he's not ...   Oct 17 2008, 20:59
|- - kornchild2002   QUOTE (DJRyanJ @ Oct 17 2008, 13:59) I...   Oct 17 2008, 21:21
|- - Canar   QUOTE (kornchild2002 @ Oct 17 2008, 13:21...   Oct 17 2008, 21:48
||- - kornchild2002   QUOTE (DJRyanJ @ Oct 17 2008, 14:40) Gene...   Oct 17 2008, 22:27
|- - kwanbis   QUOTE (kornchild2002 @ Oct 17 2008, 20:21...   Oct 19 2008, 19:25
- - Neasden   On the switch subject, I just would like to add th...   Oct 17 2008, 21:34
- - DJRyanJ   QUOTE (kornchild2002 @ Oct 17 2008, 13:21...   Oct 17 2008, 21:40
|- - Slipstreem   QUOTE (DJRyanJ @ Oct 17 2008, 21:40) What...   Oct 17 2008, 21:59
- - DJRyanJ   QUOTE (Slipstreem @ Oct 17 2008, 13:59) O...   Oct 18 2008, 01:11
|- - Synthetic Soul   QUOTE (DJRyanJ @ Oct 18 2008, 01:11) I...   Oct 18 2008, 10:00
- - Moon   Well, I'm sorry but after finding out about Pi...   Oct 18 2008, 11:11
|- - Synthetic Soul   QUOTE (Moon @ Oct 18 2008, 11:11) Well, I...   Oct 18 2008, 19:04
- - Slipstreem   With reference to your last paragraph, have you tr...   Oct 18 2008, 13:04
- - Moon   I'm gonna try em tonight. I've also conver...   Oct 18 2008, 16:36
- - pdq   If even a single frame uses 320 kbps then the enti...   Oct 18 2008, 22:16
- - Moon   QUOTE (Synthetic Soul @ Oct 18 2008, 20:0...   Oct 19 2008, 09:24
- - DJRyanJ   QUOTE (Moon @ Oct 18 2008, 03:11) a) a fu...   Oct 19 2008, 10:33
|- - Synthetic Soul   QUOTE (DJRyanJ @ Oct 19 2008, 10:33) I su...   Oct 19 2008, 11:54
|- - Moon   QUOTE (DJRyanJ @ Oct 19 2008, 11:33) QUOT...   Oct 20 2008, 09:50
- - shadowking   Dj's of the world please stop bothering us wit...   Oct 20 2008, 12:50
- - DJRyanJ   I'm trying to do some comparisons, and I'm...   Oct 21 2008, 19:58
|- - Canar   http://ff123.net/samples.html is a good place to s...   Oct 21 2008, 20:16
- - halb27   On problemSamples folder you'll find those sam...   Oct 21 2008, 20:25
- - DJRyanJ   QUOTE (Canar @ Oct 21 2008, 13:16) Howeve...   Oct 21 2008, 20:58
|- - halb27   QUOTE (DJRyanJ @ Oct 21 2008, 21:58) .. f...   Oct 21 2008, 22:06
|- - Moon   QUOTE (DJRyanJ @ Oct 21 2008, 21:58) I...   Oct 21 2008, 22:28
|- - Slipstreem   QUOTE (DJRyanJ @ Oct 21 2008, 20:58) I...   Oct 22 2008, 00:52
- - lvqcl   QUOTE It refers to the LAME problem samples page f...   Oct 21 2008, 21:09
|- - Canar   QUOTE (lvqcl @ Oct 21 2008, 13:09) http:/...   Oct 21 2008, 21:26
- - DJRyanJ   That's the plan, slipstreem. Moon, I'll s...   Oct 22 2008, 04:31


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