Re: AAC VBR and CBR

>It might be easier to detect problems if you also posted a clean version -
>the mp3 or one of the other mp4's.

Kind of hard for me to post stuff like this.  I have a 1/2 speed dial-up
connection and that's it.  But, here goes.

OK, look at http://santafe6.santamedia.com/AACTest/lame_exerpt.mp3
That one is VBR, quality level 0, highest quality encoding level.

Also, http://santafe6.santamedia.com/AACTest/PsyTel_exerpt.m4a
That one is encoded with -vbrhi -br 100 -c 16500


>Are you having the same problem with other albums?

Not yet.  The Takemitsu is the only thing I've encoded with Nero so far.
The liner notes to the Takemitsu state that the track in question was
recorded at "Watford, The Colosseum."  I did a google search, but didn't
turn up any useful info.  I can't really tell what kind of a hall it is.
The sound of the recording almost has an "environmental" feel to it...like
open air.  It made me wonder if the "tweadle" artifact was the Nero AAC's
failed attempt to cope with low-level constant background noise.

I thought I might encode the Morton Feldman "Rothko Chapel" next as a test.
It's also a very atmospheric piece.



-----Original Message-----
From: richard [mailto:[email protected]]
Sent: Wednesday, May 14, 2003 8:02 PM
To: Gordon Harris
Cc: [email protected]
Subject: RE: [ephpod] Re: AAC VBR and CBR


It might be easier to detect problems if you also posted a clean version -
the mp3 or one of the other mp4's.

Are you having the same problem with other albums?

At 06:21 PM 5/14/2003 -0600, Gordon Harris wrote:
> >I haven't had that problem.
>
> >Which version of Nero are you using - 5.5.10.0, 5.5.10.28, other?  Do you
> >hear the "tweadle" on you computer or just on the ipod?
>
>The Nero version is 5.5.10.28.  The AAC plug-in versions are:
>
>aac.dll: 2.0.0.0
>aacenc32.dll: no version info
>acmp32.dll: 1.0.0.1
>
>(All this was downloaded from Ahead just yesterday.)
>
>I just re-encoded using the Nero AAC encoder at "normal:high" with Encoder
>Quality set to "High" and AAC profile set to LC (just to make sure I hadn't
>messed up before.)
>
>I can't really hear the "tweadle" when playing back the MP4 through
Winamp2.
>My computer is frankly too loud to do any serious listening at the machine.
>And my (yuck) Creative Live 5.1 sound card does too much monkeying around
>with the sound anyway.
>
>But, I just did a quick alternate test:  I used Nero to "de-encode" it's
MP4
>file back to a WAV file.  I then burned the original WAV and the de-encoded
>WAV to an audio CD and listened on my stereo, using AKG K240 Studio (cheap
>version) headphones.  The "tweadle" is definitely there, and definitely not
>there in the original WAV.
>
>Transferring the newly encoded MP4 (m4a) to the iPod, I again heard the
>"tweadle," this time listening using Etymotic ER-4P earphones.  The
>"tweadle" is as plain as the big 'ol nose on my face.
>
>I've posted the first 1'40" of this artifactual "nero normal" M4A file at:
>http://santafe6.santamedia.com/AACTest/NeroNormalTest.m4a
>
>To my ears, the artifacts are most audible at about 1 minute in.  The file
>is 1.3 mb and I'll leave it there for 24 hours.
>
>
>
>-----Original Message-----
>From: richard [mailto:[email protected]]
>Sent: Wednesday, May 14, 2003 5:13 PM
>To: [email protected]
>Cc: [email protected]; [email protected];
>[email protected]
>Subject: Re: [ephpod] Re: AAC VBR and CBR
>
>
>I haven't had that problem.
>
>Which version of Nero are you using - 5.5.10.0, 5.5.10.28, other?  Do you
>hear the "tweadle" on you computer or just on the ipod?
>
>
>At 04:54 PM 5/14/2003 -0600, Gordon Harris wrote:
>
> >I've done some non-blind testing with the Nero AAC encoder vs. PsyTel
> >aacenc_mpeg4.exe V2.15.
> >
> >My test track was track 2 from "Quotation of Dream" by Toru Takemitsu,
> >Deutsche Grammophon 453 495-2.
> >
> >The recording (I think) was from a live performance.  Scoring is for two
> >pianos, percussion & orchestra.  The dynamics seem to be mostly P down to
> >PPPP.
> >
> >The track was extracted to a WAV via EAC and converted to Mp3 with Lame,
> >M4As with PsyTel, Nero and QTpro 6.1 and all were xfered to my winpod via
> >Ephpod 2.70a.
> >
> >In EVERY encoding I tried with the Nero AAC encoder (normal, extreme,
> >audiophile, transcoding ultra, all at high quality) the resulting M4A had
a
> >more or less (but always audible) "tweadle" in the background when played
>on
> >the iPod...which I assume is an encoding artifact (as opposed to a
decoding
> >artifact, I guess.)  Neither Lame or PsyTel seemed to suffer from this
> >artifact with this track.
> >
> >Anyone else hearing things that shouldn't be there with the Nero AAC
> >encoder?
>




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