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Topic: Real vs. Apple AAC (Read 8537 times) previous topic - next topic
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Real vs. Apple AAC

[span style='font-size:7pt;line-height:100%']Split from RealNetworks Says Files Can Play on iPod
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I encourage anyone who has any doubt whether 192 kbps AAC from the Coding Technologies encoder Real licensed, has higher sound quality than that of 128 kbps AAC from iTunes, to test for themselves. It is very easy:

  • RealPlayer and Helix Producer both come with free AAC encoding at all bitrates, encode your own test songs


I think it would be interesting, and I'm not sure of the result.

http://www.rjamorim.com/test/aac128v2/plot12z.png

It's quite possible the result of such a test would be: undecided

Real vs. Apple AAC

Reply #1 –
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It's quite possible the result of such a test would be: undecided
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... which would probably result in folks going with the iTunes codec for no other reason than to save space/carry around more music. (Which of course is the whole point of a portable player in the first place!)

  Net result: Until/unless the perceived quality is comparable at the same bitrate, RealNetworks will still be perceived as a less-desirable AAC codec.

  Of course, the Helix software offers a few things that iTunes doesn't - such as ACELP.net encoding. But sadly, there still doesn't seem to be any method/tool to re-mux ACELP.net *.rm as a proper *.aa (Audible) file, so that Helix-encoded audiobooks could be played on an iPod. Any thoughts on this, Karl?

    - M.

Real vs. Apple AAC

Reply #2 –
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It's quite possible the result of such a test would be: undecided


How can you say that? This is a listening test testing Apple's and Real's AAC at 128kbps only. Now you try to compare 128kbps Apple AAC with 192kbps Real AAC. You can't extrapolate and you can't make any other conclusions from this test. And I thought at least here at HA you should have a proper listening test or at least some ABX results before making such a claim. 
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Wtf?

I explicitly said such a test would be required because I don't agree with the claim someone made that "192kbps must be better than 128k". The encoders are of differing quality and the 128k test result *does* demonstrates that.

Both Karl and I made a personal guess what the result of such a test would be, so what is your problem exactly?

Real vs. Apple AAC

Reply #3 –
Hi All

Does anyone know how Harmony manages to allow playback of their protected AAC audio on the iPod while restricting it on iTunes.  I thought both the local and iPod SCInfo files contained the same encryption key, so iTunes should be able to play it? 

I know the SCInfo files are different because they are hashed using different system information, but the underlying encryption key should be same shouldn't it?  Or am I getting confused here?

Real vs. Apple AAC

Reply #4 –
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Wtf?

I explicitly said such a test would be required because I don't agree with the claim someone made that "192kbps must be better than 128k". The encoders are of differing quality and the 128k test result *does* demonstrates that.

Both Karl and I made a personal guess what the result of such a test would be, so what is your problem exactly?
[a href="index.php?act=findpost&pid=230272"][{POST_SNAPBACK}][/a]


My problem is that you cannot make any assumptions on the two codecs in general by Roberto's test like you are doing. The only thing you can say is that Apple 128kbps AAC is rated better than Real 128kbps AAC. The encoders are of differing quality as you say but that is proven only at 128kbps.  I haven't seen any listening tests including Apple 192kbps AAC and Real 192kbps AAC, and I certainly haven't seen any tests including Apple 128kbps AAC and Real 192kbps AAC (if there is one and I missed it, I sincerely apologize).  Karl did not make a personal guess. He invited anyone to try both encoders at the bitrates that are used at the two music stores. You made a personal guess and I don't think this board is based on personal guesses. May I remind you of TOS 8?

Real vs. Apple AAC

Reply #5 –
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My problem is that you cannot make any assumptions on the two codecs in general by Roberto's test like you are doing. The only thing you can say is that Apple 128kbps AAC is rated better than Real 128kbps AAC. The encoders are of differing quality as you say but that is proven only at 128kbps.


If the encoders are of differing quality, the logical extension *is* that they (are most likely) of differing quality too at 192kbps, and most certainly *not* the reverse.

The burden of proof is to the one that claims that they are of the same quality, and not the reverse, since the data we *do* have points to the opposite.

This doesn't even have anything to do with TOS #8, it's basic reasoning!

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Karl did not make a personal guess. He invited anyone to try both encoders at the bitrates that are used at the two music stores.


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I encourage anyone who has any doubt whether 192 kbps AAC from the Coding Technologies encoder Real licensed, has higher sound quality than that of 128 kbps AAC from iTunes, to test for themselves.


There's a very strong implication here. (Note HIS emphasis) Am I imagining things?

Shall I rephrase what I said?

"I encourage everyone who might be tempted to think 192kbps AAC from Real actually offers better quality than 128kbps AAC from iTunes, to test for themselves".

Is this acceptable to you? I don't think it makes any difference from what I already said!

Real vs. Apple AAC

Reply #6 –
How could what Garf said possibly be construed as breaking that rule? While tos8  makes this place unique and liberates it from a lot of the b.s. that is audio, it's distracting when applied with an itchy trigger finger and willevolve into high school geometry if everyone has to prove everything they write. i just hate to see the concept diluted by abusing it and throwing it around incorrectly.

Real vs. Apple AAC

Reply #7 –
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If the encoders are of differing quality, the logical extension *is* that they (are most likely) of differing quality too at 192kbps, and most certainly *not* the reverse.

The burden of proof is to the one that claims that they are of the same quality, and not the reverse, since the data we *do* have points to the opposite.

My point is that you do not have any data concerning the bitrates we are talking about and therefore we cannot make any assumption on the quality of both encoders. I'm not saying that Real 192kbps AAC is better than Apple 128kbps AAC. I'm just saying we do not know, because there hasn't been any proof about it. And I am pointing out that there doesn't exist such a thing as a logical extension. You just can't extrapolate results like that. The data we do have right now are completely irrelevant to the point of argument here.

As for Karl's statement, I don't think that you or me or anybody else can refrase anything somebody else says. The meaning of a sentence can be changed very easily by the change of a single word. What I understood from his original statement is totally different from what you understood and that's it.

Real vs. Apple AAC

Reply #8 –
I only refrased what I said myself. I quoted Karl literally, including his own emphasis.

If encoder A is known to perform better than encoder B at one bitrate, I will assume A performs better than B also at another bitrate, unless there are indications or proof to the contrary. That is very simple, logical, and used throughout these forums. And it has *nothing* to do with TOS #8.

And it would be nice if this discussion is split because I agree it's completely offtopic.

Real vs. Apple AAC

Reply #9 –
I would like to re-iterate my suggestion: it is amazingly simple for anyone to test the two encoders for themselves at the two bitrates in question, since both are available for free. If you use any of the music stores, it would probably be an even better idea to purchase the same song from both stores, to verify the store quality, since no one really knows for sure how the songs are encoded. For instance, there could even be other factors involved : what if the source is actually not lossless, the studios may decide which source format they supply the stores with.

If you would like to try the latest RealPlayer to encode AAC at 192 kbps, here is suggested reading for the experienced media player user.
Sr. Codec Engineer (video) | RealNetworks Codec Group | helixcommunity.org 
This information is provided "AS IS" with no warranties,  grants no rights, and reflects my personal opinion.
 

Real vs. Apple AAC

Reply #10 –
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If encoder A is known to perform better than encoder B at one bitrate, I will assume A performs better than B also at another bitrate, unless there are indications or proof to the contrary. That is very simple, logical, and used throughout these forums. And it has *nothing* to do with TOS #8.
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And that is exactly where you are wrong in my opinion. And it has everything to do with TOS 8 as I see it. TOS 8 makes it clear that you are not allowed to make assumptions about sound quality. If you say something that is a proven fact, it's OK. If it is not, you have to prove it yourself in order to say it. Simple as that. Maybe a mod should make a comment on this assumption thing. For instance, if we were to make assumptions like that and taking into consideration the latest multiformat 128kbps test by Roberto, we could conclude that aoTuV vorbis is the best encoder throughout the whole lossy bitrate range, but that would be wrong, wouldn't it?

Real vs. Apple AAC

Reply #11 –
Rather than arguing ad nasuem about the intricacies of codec scaling and TOS #8, why don't we be good scientists here and just start testing? That's the only objective way to answer the question of quality. I have a copy of Real 10 on VPC and can play around with some samples later, and will see if Real AAC @ 192kbps can be distinguished from iTunes @ 128. If they do sound different, we will know which one is the better store to purchase electronic music from. I encourage others to do the same, even for just 1 sample.

Real vs. Apple AAC

Reply #12 –
It would be wrong because there are other tests which prove that it's false at lower bitrates, and there are good indications MPC is better if you go higher. (Note that this is *exactly* in line with what I said above).

I believe the aoTuV result at 128kbps does make it fair to say that aoTuV is "quite likely" the best or among the best encoders at 140kbps and at 100kbps, without having to provide further proof of that.

It believe it used to be so that TOS 8 explictly mentioned proof being required (only) for statements that were against logic/current knowledge.

Requiring hard proof for *any* statement as you are doing now will make any sensible discussion totally impossible.

So I wonder as well what the intention is, whether the change was intentional and whether or not people agree with my statements above.

Real vs. Apple AAC

Reply #13 –
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It believe it used to be so that TOS 8 explictly mentioned proof being required (only) for statements that were against logic/current knowledge.


My own logic is telling me that it is quite likely that Real AAC 192 is better than Apple AAC 128. Apple's encoder is better at 128k (and possibly on the whole range), but Real's one would have to be quite bad to not be able to be better with 50% more bits.

but only tests can check....

Real vs. Apple AAC

Reply #14 –
At the upper end of the quality range things bend...FLAC might not be able to beat MPC standard with 6 times the bits, if you get what I mean :-/ That's why I said an "undecided" result is possible.

Real vs. Apple AAC

Reply #15 –
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It believe it used to be so that TOS 8 explictly mentioned proof being required (only) for statements that were against logic/current knowledge.

Well it certainly is not this way now:
Code: [Select]
8. All members that put forth a statement concerning subjective sound quality, must -- to the best of their ability -- provide objective support for their claims. Acceptable means of support are double blind listening tests (ABX or ABC/HR) demonstrating that the member can discern a difference perceptually, together with a test sample to allow others to reproduce their findings. Graphs, non-blind listening tests, waveform difference comparisons, and so on, are not acceptable means of providing support.

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Requiring hard proof for *any* statement as you are doing now will make any sensible discussion totally impossible.

I don't believe so. I'm not talking about *any* statement. I'm talking about any statement about sound quality. It would just make the discussion have scientific basis and that is exactly what TOS 8 is all about.
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So I wonder as well what the intention is, whether the change was intentional and whether or not people agree with my statements above.
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You don't have to wonder about my intentions. They are quite clear actually. I jumped at your "personal guess" because I do not want this to become a trend here. What if a newbie came asking the usual question: codec A or codec B? And the answer was: No listening tests have been made so far regarding these codecs at the settings you are referring to but my personal guess is codec A is better than codec B.

EDIT: anyway, I'm going to follow Cygnus's proposal and make a small test tomorrow.

Real vs. Apple AAC

Reply #16 –
I was referring to the intention of the TOS change, if there was one

Real vs. Apple AAC

Reply #17 –
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I was referring to the intention of the TOS change, if there was one
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Oops... sorry about that then. 

Real vs. Apple AAC

Reply #18 –
OK. I had a small ABX session with two samples. I used the waiting and blackwater samples. You can find both in ff123's page. The bitrates used where 128kbps for iTunes 4.2 AAC and 192kbps for Real AAC. There were no test sessions and I went for 10 trials. Anyway, these are all my results:

Code: [Select]
File A: file://D:\test\Blackwater.wav
File B: file://D:\test\Blackwater_Apple.m4a

16:41:58 : Test started.
16:54:20 : 01/01  50.0%
16:54:49 : 02/02  25.0%
16:55:19 : 03/03  12.5%
16:55:53 : 04/04  6.3%
16:56:21 : 05/05  3.1%
16:56:42 : 06/06  1.6%
16:56:56 : 07/07  0.8%
16:57:10 : 08/08  0.4%
16:57:27 : 09/09  0.2%
16:57:44 : 10/10  0.1%
16:57:46 : Test finished.

 ---------- 
Total: 10/10 (0.1%)

Once I found my artifact it was relatively easy to ABX. I concentrated on the last acoustic guitar strum.

Code: [Select]
File A: file://D:\test\Waiting.wav
File B: file://D:\test\Waiting_Apple.m4a

16:24:16 : Test started.
16:24:55 : 01/01  50.0%
16:25:09 : 02/02  25.0%
16:25:19 : 03/03  12.5%
16:25:27 : 04/04  6.3%
16:25:51 : 05/05  3.1%
16:26:06 : 06/06  1.6%
16:26:28 : 07/07  0.8%
16:26:44 : 08/08  0.4%
16:26:59 : 09/09  0.2%
16:27:12 : 10/10  0.1%
16:27:14 : Test finished.

 ---------- 
Total: 10/10 (0.1%)

I knew this sample pretty well and ABX was easy with Apple AAC. There is the 'f' in the word 'for' around 03:00 sec that is distorted somehow.

I could not ABX any of the two samples using the Real encoder. Any of the artifacts I found in Apple's encoder where gone here. I believe this is a (limited) indication that Real's codec at 192kbps is superior to Apple's codec at 128kbps.

I would like to make more tests, but I do not have the time right now and I do not consider myself golden-eared anyway. If anybody else wants to contribute, go ahead. 

edit: typo

Real vs. Apple AAC

Reply #19 –
Can you upload the 2x2 m4a's? I'd like to give it a spin too but I don't want to install iTunes or Real's stuff.

Real vs. Apple AAC

Reply #20 –
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The burden of proof is to the one that claims that they are of the same quality, and not the reverse, since the data we *do* have points to the opposite.


A "burden of the proof" can never be on the side of someone claiming identical quality, because such a thing can't be proven !
This is the first thing to consider in order to find where the burden lies. Previous tests results and the context of the discussion come next. 

Real vs. Apple AAC

Reply #21 –
You are 100% right - I did not mean equal, but "close enough there are no big or obvious differences". But I think that was clear, anyway?

Specifically I meant that it could be hard to statistically prove them having different quality, which is as you point out not the same thing than statistically proving them equal

Real vs. Apple AAC

Reply #22 –
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Can you upload the 2x2 m4a's? I'd like to give it a spin too but I don't want to install iTunes or Real's stuff.
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Sure. Get them [a href="http://www.hydrogenaudio.org/forums/index.php?showtopic=24614]here.[/url]

Real vs. Apple AAC

Reply #23 –
Garf, I took me some time to understand what you mean correctly.
If I am not wrong, you are not suggesting that Real 192 could have a similar quality to Apple 128, but instead that they could be statistically tied because for many users Apple 128 is already transparent?

Real vs. Apple AAC

Reply #24 –
Yes, exactly. (That effect and me thinking that Apple's encoder is better)