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Topic: Informed rebuttal of VBR disadvantages appreciated (Read 42531 times) previous topic - next topic
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Informed rebuttal of VBR disadvantages appreciated

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!

Informed rebuttal of VBR disadvantages appreciated

Reply #1
Don't waste your energy. Self-absorbed people like him will never change their narrow-minded opinion.

Also the CDJ-200 is not an MP3-player since it does not implement the standard.
If Pioneer really based the lack of VBR support on opinions of people like this they have made clear that they don't care. Therefore the only language Pioneer will understand is money, so look out for alternative products and don't support them any longer.

Informed rebuttal of VBR disadvantages appreciated

Reply #2
It's all up to whether an encoder works well. Good VBR encoders like Lame 3.98, Nero AAC, Vorbis work fine.
lame3995o -Q1.7 --lowpass 17

Informed rebuttal of VBR disadvantages appreciated

Reply #3
Yes, don't waste your time. That guy is completely wrong in everything he says, and he's arrogant about it too.

He talks about MP3 VBR taking "horsepower" like it's some monstrous task like raytracing or weather simulation. I haven't done any CBR vs. VBR speed tests (because I couldn't care less), but if my tiny iPod can decode MP3 VBR for 24 hours straight, I have a hard time imagining a stationary hardware player like the Pioneer units lack the computing power to decode it.

Informed rebuttal of VBR disadvantages appreciated

Reply #4
As the other guys have already said, you're wasting your time with him as he already seems to have decided that he knows exactly how VBR works when it seems fairly clear that he doesn't. However, in the second thread you link to he claims that VBR suffers from latency when making decisions regarding increasing/decreasing the bitrate when necessary.

I believe this to be true of some (or maybe most) VBR encoders, but the Hydrogenaudio LAME WIKI clearly states that...
Quote
Unlike other MP3 encoders which do VBR encoding based on predictions of output quality, LAME's default VBR method tests the actual output quality to ensure the desired quality level is always achieved.
This does seem to infer that LAME VBR is intelligent enough to know what bitrate to use and when to use it rather than just guessing and using a slewed approximation with no real-time, output-related feedback which seems to be his inference for the majority of VBR encoders. I would go and point this out to Pulse, but I've wasted too much time on his type in the past to be honest.

To further back up what Raiden said earlier, there are some official MP3 compliance tests HERE (defined as "ISO/IEC international standard IS 11172, part 3 - audio"). If the Pioneer deck in question doesn't play ALL of the files in the official Layer3 compliance tarball without error (which includes a VBR test file) then it IS NOT an MP3 compliant player and, IMHO, shouldn't be marketed as such. Assuming that the player is marketed as such and fails the compliance tests (I haven't tested one, so I'm merely speculating), I'd be demanding a full refund had I bought one.

Call me paranoid, but it worries me to see the words "Pioneer National Trainer // Product Specialist" in his signature.

Cheers, Slipstreem. 

Informed rebuttal of VBR disadvantages appreciated

Reply #5
No point with some of these people....I've given up arguing with people like that....just let them be all smug and happy in their small world

Informed rebuttal of VBR disadvantages appreciated

Reply #6
Call me paranoid, but it worries me to see the words "Pioneer National Trainer // Product Specialist" in his signature.


My thoughts exactly.
feedback will set you free

Informed rebuttal of VBR disadvantages appreciated

Reply #7
These threads are really old. I created an account to try get some kind of rebuttal out of Pulse, but I'm not even sure he's still active. I responded to the second, newer thread. There's a lot of misinformation being spun around there, like talk about transcoding VBR to CBR and whatnot. Utter nonsense!

Informed rebuttal of VBR disadvantages appreciated

Reply #8
I responded to the second, newer thread.
Kudos for the effort. I may be going mad, but I think you may have used "MP3" when you mean to use "VBR" in at least one place.

Edit: and yes, his post regarding transcoding almost had me registering with the forum!  Arse.

Edit 2: An average of 30 posts a day?!  And he is still active; very active yesterday.
I'm on a horse.

Informed rebuttal of VBR disadvantages appreciated

Reply #9


Call me paranoid, but it worries me to see the words "Pioneer National Trainer // Product Specialist" in his signature. :rolleyes:


My thoughts exactly.

I'm not surprised. A title in nowadays industry doesn't mean much regarding competence.
I am arrogant and I can afford it because I deliver.

Informed rebuttal of VBR disadvantages appreciated

Reply #10
No, I think I'm going mad. That post I made is quite unclear. Some other guy responded to me with a wall of verbiage that seems to completely miss the point.

Oh boy:
Quote
that's plenty of space saving for me, since I can't tell the difference between a WAV and a 320kbps MP3 - but I CAN tell the difference between that and a VBR MP3, or that and a 128kbps MP3.


I'm going to mull this over a bit and respond sometime this evening... what nonsense.

Informed rebuttal of VBR disadvantages appreciated

Reply #11
Well, we have an answer of sorts over there from a different member, but it looks like pure bullcrap to me.

Windows Task Manager shows exactly the same resource usage here when playing back the same track encoded in either 128Kbps CBR or LAME VBR at -V3. I've checked this out in Winamp and Foobar2000.

He also talks about VBR as being a global thing without making any reference to actual quality setting with the phrase, "I can't tell the difference between a WAV and a 320kbps MP3 - but I CAN tell the difference between that and a VBR MP3...". Which encoder and what setting, numpty?! 

Next! 

Cheers, Slipstreem. 

Informed rebuttal of VBR disadvantages appreciated

Reply #12
Mind, if you do decide to argue:
The argument that CQ VBR is better than  <320 CBR should be easy to prove in theory, but very hard to prove in practice
The best encoder is still not a human "ear" and can make mistakes regarding needed bitrate.
Unless you understand the encoding process well enough to defend the VBR methodology, it will be easy for a bull-headed fool to trip you up, giving him (?) another false sense of victory.
Creature of habit.

Informed rebuttal of VBR disadvantages appreciated

Reply #13
I'm specifically not joining that forum as I'm too argumentative when riled to get my point across succinctly, but it might be worth asking anyone who claims that they can hear the difference to at least take an ABX test for themselves rather than them making blind assumptions and misleading others. Refusal to do so would prove pigheadedness and/or a reluctance to discover the truth on the part of the opponent.

It doesn't matter what a person can or can't prove in theory if they hear no difference in practice.

Cheers, Slipstreem. 

Informed rebuttal of VBR disadvantages appreciated

Reply #14
No, I think I'm going mad. That post I made is quite unclear. Some other guy responded to me with a wall of verbiage that seems to completely miss the point.


Quote
Basic lesson in computing: ALL instructions and data to be operated upon must exist in RAM. If the instruction or data is external to the RAM, the system must first copy it into RAM (from wherever - Hard Disk, CD, whatever) before it can be used by the CPU. The CPU has no direct access to the hard drive (or, in the case of the CD player, the CD), it must go through the RAM. The CPU also has to actually execute the copying of things into RAM (which in reality is actually handed off to the chipset in the machine, but the chipset won't operate on anything unless it is told to do so by the CPU).

So, as each frame is read to be decoded, it is copied into RAM (quite probably more than one frame at a time, however).

What happens (in an oversimplified manner) is this: the processor that is decoding the frame is dumb. It doesn't know where the frame ends, it just keeps operating on streams of data - possibly operating into some area of the memory that contains something else that isn't MP3 data. This is known as buffer overflow, and can cause crashes and/or bad sounding music playback. This is prevented by setting something called a buffer size - it knows how much data it must read before stopping.

If every frame that is copied into RAM to be operated on is a different size, the CPU needs to be told of this, executing an extra instruction that sets its buffer size. This means that every frame needs at least 2 operations to work - the buffer set, and the buffer read/operate. In a particularly variable MP3, for example, where the frame size is changing A LOT from one to the next, the CPU can't read nearly as much data "ahead" because it never knows where the end will be, and it might read too far before the memory is copied (because a CPU operates many many times faster than the hard drive, or CD, can write data to the RAM) and hit a buffer overflow, causing issues of unknown result. Also, since the CPU is in charge of ALL the RAM and is also doing other things (both in a CD player and in a normal computer), every time it resizes the RAM buffer (because it's copying frames of varying sizes), it might copy something to the area that was occupied by a larger frame but is now free before it needs to use it for audio data again. Now, if it needs to fill that space with audio data (because splitting up a frame in memory would be very bad), it has to MOVE what's there before it can copy new data into that space. This eats up time and processor resources.


Oh yeah I see what you mean Canar. It's so nice of him to give you a basic lesson in computing isn't it .

Really most of what he has posted is just so much rubbish it's ridiculous. Like the suggestion setting a buffer length is a significant part (as in computer load) of decoding an mp3 frame. I'd say he's got no idea of the relative amount of cpu time to do a couple of integer instructions to set up a buffer length compared with even just one part of the mp3 decoding like the DCT for example. I hope there's a developer or two here to read this "basic computing lesson" and make some "constructive critism". Pretty funny stuff really.

Informed rebuttal of VBR disadvantages appreciated

Reply #15
Who is BDX?

Informed rebuttal of VBR disadvantages appreciated

Reply #16
I dont know, it's not me. Does anyone have a transcript of exactly what he said to banned anyway?

Informed rebuttal of VBR disadvantages appreciated

Reply #17
It wasn't me either, and I don't have a transcript but the post suggested that if compression ratio was irrelevant then a person might as well stick to WAV in the first place. There was a dig concerning the Pioneer DJ players not being true MP3 players if they didn't support VBR properly, and I thought that was totally fair to be honest.

Maybe a few more of us should join and flood them with the truth faster than they can delete it.

Cheers, Slipstreem. 

Informed rebuttal of VBR disadvantages appreciated

Reply #18
I will post just to be ballsy.  I don't see Pulse using any logic in their statements so I see no reason to use logic in mine.  I will though.

Informed rebuttal of VBR disadvantages appreciated

Reply #19
Alright guys, I'm the guy who did the wall of verbiage.  I'm here to defend myself (a little - please read what I have to say carefully before flamage  ).

1) I LOVE being proven wrong.  It means I've learned something.  I'm here to be educated.

2) I'm a DJ first.  While I have many posts at Pioneer, I'm not exclusive to their equipment - I use (and pay for) whatever fits my needs best.  In fact, the only piece of Pioneer gear I currently own is a pair of headphones.

3) I did miss the point in my "wall of verbiage".  I'm going to go and fix it.

4) I wasn't clear in my comment: "... I can't tell the difference between a WAV and a 320kbps MP3 - but I CAN tell the difference between that and a VBR MP3, or that and a 128kbps MP3."  I should have added to that "from certain encoders".  I think that it's generally accepted that certain encoders (both the software and human kind  ) and the settings used with them are inferior and can really mess up the sound in your file.  Please correct me if I'm wrong.

5) We know that MP3 is lossy.  We know that it won't have the best sound quality when compared to a lossless algorithm - you people here at HA will know that better than anyone given the breadth of the forums.  Unfortunately, MOST people who use MP3 either can't tell the difference or just don't care.  As a DJ I believe it's part of my JOB to care - I don't want to be promoting BAD sounding music, as some DJ's do that go ONLY use filesharing as a means to get their music, which more often than not results in a crappy-sounding MP3 from some n00b who doesn't know any better.

6) CPU's, whether in a computer or a CD deck, have more than enough horsepower to handle a VBR, regardless of the back-end so-called extra processing that may or may not be required (I believe it is, negligible as it may be).  Personally, I think that Pioneer's (shoddy) support of it comes down to not taking the time to handle all the exceptions and broken MP3's that occur with so many internet-shared MP3's out there, VBR or otherwise.  It's no secret that the boys over at Serato Scratch Live have spent countless hours refining their program to handle those broken MP3's - a quick forum search over there reveals the mods and dev team constantly requesting files that don't play right so they can find out why they're broken.  They're a big company, but I think Pioneer is bigger - why can't their engineers do the same?

7) In a club or other loud DJ environment, I'm pretty sure that NO ONE can tell the difference between even a 128kbps CBR MP3 and something better.  I don't think it matters how good the sound system is, there's just too much ambient noise.  I know I can't, as long as the MP3 is well encoded.

8) With #7 in mind, who am I to decide who can and can't hear things?  So, I choose to encode my MP3's at 320kbps CBR so that I give my crowd the best possible chance at hearing the music in the way it was originally recorded.

9) With #8 in mind, who is MY ENCODER to decide what is a difficult passage or not in the VBR encoding process?  I know that I'm already losing data to the encoding process, I would rather not lose any more than I have to.

10) I would say that the POINT of MP3 (or any other compression algorithm) is to reduce filesize either for storage or transfer (say over the internet).  But, as mentioned in the other forum, storage is getting cheaper, as is bandwidth (at least where I live).  I choose to use MP3's because the collection I carry around with me is too big to fit (in WAV format) on today's hard disks (~500GB at 320kbps) in a portable format.  Since I play out with my MP3 collection and don't use CD's anymore, keeping everything in WAV would be damn near impossible unless I carted SEVERAL 1TB disks around.  And since my music collection is part of my livelihood, my drive is a RAID 1 external USB enclosure.  So for every drive I take, I now need TWO - cheap or not, this is getting more and more expensive.  The tradeoff, for me, came at that point.  I'm willing to accept MP3's lossy format at 320kbps because of practicality.  I understand that other people's "tradeoff" point is different from mine.

It could be argued that I don't need that much music and there I will agree with you.  Most often I could play certain shows off of less than 2 or 3 GB of files, call it 10 to 15GB of WAV files.  I just never know what I'm going to need, so I carry everything.

11) I consider myself a professional when it comes to being a DJ.  That means that I strive for excellence, and (perhaps unfairly) compare myself to other professionals, such as doctors.  In an (admittedly flawed) analogy, a doctor with a shoddy education doesn't get a very favorable review; by the same token, a DJ using shoddy music won't either.  Education is the base of the doctor's craft; music is the base of the DJ's.

Basically my point is this: VBR is an acceptable alternative to CBR these days, no question - if it's for personal use.  Pioneer's lack of support for it in one CD player is crap, IMHO, as is their generally shoddy support for it.  But, from my experience, VBR is easier to screw up than CBR.  So, I stick with CBR because I'd really rather not take the chance, either that the CD player is going to hose it up or that my ears won't like how it sounds.  I also promote using CBR's because I believe (as I said) that CBR's leave the least chance of error for people who (IMHO) SHOULD use the highest quality music that they can, or believe is good for them.  I DO NOT believe that a VBR MP3 is acceptable, FOR ME, since I consider myself a professional.  And since I listen to other DJ's, I like them to use good-quality stuff too

So there is another wall of verbiage for you - sorry I can't be more succinct.  I'm going to go put my flame suit on and wait to see what you guys have to say

-r-

Informed rebuttal of VBR disadvantages appreciated

Reply #20
I don't have the time right now to get more in-depth (studying for a third-year computer science midterm which I have in 1.5h), but thank you for the post. You're being cogent.

Pre-echo is really obvious to trained ears, and occurs in high-order bits. That means that it can be obvious even with high noise-floors.

When making claims like "VBR is an acceptable alternative to CBR these days" Hydrogenaudio tends to require that such claims are backed up by blind testing (generally ABX tests around these parts). In most cases, properly-tuned VBR presets in LAME are indistinguishable from the original source. Nevertheless, there are particular samples for which even 320kbps CBR is not sufficient, even on shoddy hardware (I've ABXed castanets.wav on $40 headphones).

Either space is a concern or space is not a concern. I'm not convinced that LAME 320kbps CBR is sufficiently distinguishable from LAME V2 VBR to warrant the extra bits (around 60% larger). If space is not a concern, lossless should be great (around 150% larger than 320CBR), and has absolutely zero loss to worry about.

Informed rebuttal of VBR disadvantages appreciated

Reply #21
...So, I choose to encode my MP3's at 320kbps CBR so that I give my crowd the best possible chance at hearing the music in the way it was originally recorded. ...
...I DO NOT believe that a VBR MP3 is acceptable, FOR ME, since I consider myself a professional.  And since I listen to other DJ's, I like them to use good-quality stuff too ...

This sounds a lot more reasonable than when reading the quoted passages.
There's nothing wrong using CBR 320 with regard to minimizing the risk of wrong encoder decisions which can happen. But you should be aware that there are many possibilities for an encoder to go wrong:
  • when deciding for using long or short blocks
  • when deciding for l/r or m/s (decision can be avoided by using plain stereo but at the expense of a lower encoding precision as a tendency)
  • when deciding for the amount of audio data required for a frame. In contrary to what you are thinking this process is involved also with CBR. CBR means constant frame data rate. Audio data rate however is variable also in the case of CBR as audio data can expand beyond frame border as well as not cover up an entire frame. It is true however that the decision process is less prone to errors when CBR or ABR is used. There is no reason however  to general disbelieve in the VBR process of a good encoder like current Lame in the case of mp3.
  • I'm sure there are a lot more decision making problems for an encoder no matter whether it uses CBR or VBR.
As I said it's okay to play it safe to the utmost extent if you like to and don't have to care much about file size. But in a practical sense you shouldn't feel really safer than when using -V0.
If you're looking at seriously bad encoded tracks it turns out that it's not VBR which is to blame. Take for instance extremely bad pre-echo sample eig (you'll find it in this forum). The majority of mp3 encoders will produce a very bad result even when using CBR 320. Contrast this to Lame 3.98's behavior when using best VBR quality -V0: the result isn't perfect but a lot better than that of many encoders' CBR 320 results (the Lame 3.98 CBR 320 result is of course as fine as the -V0 result).
The fact that perfection can't be achieved with mp3 is the reason why most members here prefer an encoder setting which produces smaller files than when using CBR 320. The quality achieved is identical in a practical sense no matter whether you use -V0, ABR 270 or similar, or CBR 320. Compared to such a setting most members here prefer a lower quality demand like when using -V3 or -V2, simply because there's nothing wrong with the quality except on rare occasion (in which a higher quality setting often brings only a minor improvement). So it's a personal choice which quality setting to use, quality difference is zero in most cases, and it's only about how to handle the rare exceptions to this.

Unfortunately you're a bit on a mission and you're wrong with this. You dislike VBR so much that you wrote a lot of fancy stuff about VBR's speed penalty which is really nonsense. With respect to quality you put the blame on VBR for no really existing reason (or do you have samples to back up your opinion?). You're disrespecting the fact that the results of high quality VBR settings are fine, and in those rare cases where they're not you cannot expect to get better results from CBR 320 compared to those of -V0.
lame3995o -Q1.7 --lowpass 17

Informed rebuttal of VBR disadvantages appreciated

Reply #22
5) We know that MP3 is lossy.  We know that it won't have the best sound quality when compared to a lossless algorithm - you people here at HA will know that better than anyone given the breadth of the forums.  Unfortunately, MOST people who use MP3 either can't tell the difference or just don't care.  As a DJ I believe it's part of my JOB to care - I don't want to be promoting BAD sounding music, as some DJ's do that go ONLY use filesharing as a means to get their music, which more often than not results in a crappy-sounding MP3 from some n00b who doesn't know any better.

10) I would say that the POINT of MP3 (or any other compression algorithm) is to reduce filesize either for storage or transfer (say over the internet).  But, as mentioned in the other forum, storage is getting cheaper, as is bandwidth (at least where I live).  I choose to use MP3's because the collection I carry around with me is too big to fit (in WAV format) on today's hard disks (~500GB at 320kbps) in a portable format.  Since I play out with my MP3 collection and don't use CD's anymore, keeping everything in WAV would be damn near impossible unless I carted SEVERAL 1TB disks around.  And since my music collection is part of my livelihood, my drive is a RAID 1 external USB enclosure.  So for every drive I take, I now need TWO - cheap or not, this is getting more and more expensive.  The tradeoff, for me, came at that point.  I'm willing to accept MP3's lossy format at 320kbps because of practicality.  I understand that other people's "tradeoff" point is different from mine.

If "your JOB (is) to care" use FLAC.

...I DO NOT believe that a VBR MP3 is acceptable, FOR ME, since I consider myself a professional.  And since I listen to other DJ's, I like them to use good-quality stuff too ...

Did you ever do a double blind test? As much as I tried, i could not tel VBR (~128kbps) from the original on the last listening test.

Informed rebuttal of VBR disadvantages appreciated

Reply #23
Pioneer should support VBR and stfu. If using VBR presents some kind of unadvantage to some type of usages of the equipment they should just explain it to their users, instead of just not supporting VBR. Is it that hard nowadays to properly support the standard?

On the other side, if one has to use MP3 and if lots of post processing is going to be used, I think CBR 320 may be a wise choice, even if sometimes VBR may be better.

Saying that VBR is (generally) worse than CBR just reveals ignorance. Let them live in the stone age and don't the let them even know that most modern audio and video formats use VBR by default for quality reasons.

Informed rebuttal of VBR disadvantages appreciated

Reply #24
OK, I have a brief moment here before my midterm so I'm going to try to reply to some of what you have said.

Quote
Is it that hard nowadays to properly support the standard?


I'd say no.  The problem that many users come across is that the MP3's that they're using ARE NOT encoded to standard, and/or are broken in some way, and Pioneer's support for broken MP3's is questionable at best.  It's absolutely unbelievable how many BAD/CORRUPT MP3's are out there that will still play in even a half-decent player/software, giving no indication that it's broken.

That said, I agree - the support should be improved to account for those corrupt MP3's that play just fine on most players/software.  On the same note, Steinberg should also step up - I use Wavelab 5.0 and I can tell you for free that there are plenty of MP3's out there it can't seem to decode.  But the second I throw them into Winamp (free, as we all know), presto-chango, Winamp can read it.  Why can't an EXPENSIVE program like Wavelab?  Weird.

The reason I try to steer the Pio forum members away from VBR is just because of the fact that many of them use filesharing for their music sources, and many of them would never bother to check if the thing is broken before trying to use it (either because they don't have the technical knowledge, don't care, or aren't aware that it's possible), which could result in a show stopper for them.  As a work-around to Pio's shoddy VBR support, I just say "don't use it".  I agree that my explanations up to now have been misleading; I'll stop doing that now that I know better.

Quote
... don't ... let them even know that most modern audio and video formats use VBR by default for quality reasons.


Which ones?  I'm curious...

Quote
If "your JOB (is) to care" use FLAC.


I would, if the program I use to playback on supported it (Serato Scratch Live).  Unfortunately for me, it doesn't.  So I "accept" MP3's.

Quote
Did you ever do a double blind test? As much as I tried, i could not tel VBR (~128kbps) from the original on the last listening test.


Not on VBR.  But I have on other things.  I'd be happy to try, just point me in the direction.

Quote
...wrote a lot of fancy stuff about VBR's speed penalty which is really nonsense. And with respect to quality you put the blame on VBR for no really existing reason.


Point conceded, but I'll be looking into this a bit more when I can to see what's actually going on (if possible).

Quote
The fact that perfection can't be achieved with mp3 is the reason why most members here prefer an encoder setting which produces smaller files than when using CBR 320.


This is a good point, and something I hadn't considered before.

Thanks for everything so far.  I'll keep watching this, but I have a midterm and a busy night ahead of me.  I'll post when I can.

-r-