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HydrogenAudio

Lossy Audio Compression => AAC => AAC - Tech => Topic started by: Pete7874 on 2012-01-05 22:11:34

Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Pete7874 on 2012-01-05 22:11:34
Hello,

I'm using Nero 1.5.4.0 AAC codec in Foobar 1.1.10.  I converted the same source file to AAC using two different settings: q0.38 and q0.40.  Theoretically, the q0.38 should have resulted in smaller file/lower bitrate.  However, the resulting files were just the opposite - the q0.38 file ended up being larger / higher bit rate than the q0.40 file.  How can that be?

I realize this is rather academic as nobody could potentially tell the two apart in ABX listening.  I just found it a bit abnormal.

Thanks!

Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: lvqcl on 2012-01-05 22:43:13
according to my rather old tests:

Code: [Select]
0.38  => 121.9 kbps (on average, of course)
0.39  => 126.7 kbps
0.393 => 128.1 kbps
0.394 => 125.5 kbps
0.4   => 128.4 kbps
...etc
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Pete7874 on 2012-01-05 23:08:40
I suppose it depends on the source material.  I just tried it again with a bunch of additional files, and in majority of cases, -q0.38 again delivered higher bit rates and file sizes than -q0.40.  There were a couple of exceptions though.
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: greynol on 2012-01-06 00:20:54
Where is the cutoff between LC and HE?
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: lvqcl on 2012-01-06 00:44:11
IIRC 0.309 - 0.31
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Shandra on 2012-01-10 23:57:20
By coincidence I encountered the same problem just a few days ago :insane: but haven't checked in this Forum so far but over at Doom9 (this threat (http://forum.doom9.org/showthread.php?t=163734)) so I missed it allready beeing a topic here. Though there you will only find  my results on a few sources and no more "findings" for now.
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Shandra on 2012-01-15 15:57:03
Btw. Where your sources where you find the problem 48kHz samples?
As I now experienced it happen on that sampling rate, but not when downsampled to 44.1kHz...
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Pete7874 on 2012-01-15 16:36:34
Quote from: Shandra on
Btw. Where your sources where you find the problem 48kHz samples?

Nope. All my sources were 44.1kHz material.
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: lvqcl on 2012-01-15 16:42:33
Mine too.
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Shandra on 2012-01-17 17:52:16
Sigh - So there must be another parameter causing this. As for me - I encountered the anomaly with DVD Sources (48kHz) but not for CD Sources (44.1 kHz), and it didn't showed up when I downsampled the 48kHz to 44.1 kHz - Besides from Source, are you both sure the resulting MP4 was still 48kHz (Though I assume so, otherwise you would have mentioned it)? Would have been to nice to find a cause that could have been used for a bug report or such :/
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: lvqcl on 2012-01-17 18:53:45
Not a bug: http://www.hydrogenaudio.org/forums/index....st&p=526757 (http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=58635&view=findpost&p=526757)
Title: Nero encoder 1.5.4.0—lower quality makes larger file; how can this be?
Post by: Shandra on 2012-01-19 01:50:14
Thanks lvqcl!

As I was just fiddling around with Nero AAC and how low I may go with the quality setting with my VHS and Digital Media Backups without sacrificing audio transparency for visual bitrates that topic annoyed me pretty badly - as from 1st sight I was unsure whether the Nero Encodes may be faulty somehow or that I may be doing something wrong in my chain of decoders/encoders!
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