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Sample specific discussions: sample #2, Public MP3 listening test @ 128 kbps
Alex B
post Nov 26 2008, 14:45
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As I said in the test results thread I would like to discuss about each sample separately. The overall results were tied and all encoders seem to be equal. In closer inspection it seems that each encoder had problems with at least some samples.

It would be useful to analyze each sample separately in order to find out what kind of problems the testers noticed and how severe they are. The discussion would help to understand the test results and probably also help the codec developers in their work. This has not been done before, but I think the outcome would be valuable.

Some testers added comments to the result files. Those comments are useful if the tester intends to revisit a saved session later. Unfortunately the comments in the result files are quite hidden and they cannot be easily evaluated and compared. That's why I didn't add comments to my results (expect the some unfinished, partially wrong comments in one of my first result files - I meant to delete them, but I forgot to do that.)

This thread is for the Sample #2. Please try to keep the discussion on topic. If you want to discuss about any other sample feel free to start a new thread for it. I am hoping that eventually we'll have 14 separate threads - one for each sample. I'll add them by myself if others have not done that before me.


Sample #2 - Vangelis_Chariots_of_Fire

The overall results:



The results from the individual testers:



I sorted the testers so that the most critical tester is the first on the left.

Since Sebastian already removed the test sample links I uploaded the first two sample packages to RapidShare so that anyone can listen to the actual samples: http://rapidshare.com/files/167567675/Samples_01_and_02.zip (7.5 MB)


I'll check my results and relisten to the samples later today. I'll post my personal comments after that.

This post has been edited by Alex B: Nov 26 2008, 15:11


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Alex B
post Nov 26 2008, 22:42
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My results:
iTunes: 3.80
LAME 3.98: 2.60
Low anchor: 1.40
FhG: 2.80
LAME 3.97: 2.20
Helix: 3.10
Lame 3.97 suffers from the sandpaper problem.
LAME 3.98 has pronounced high frequency hiss. (I don't know why that bothered me so much when I tested this sample. The other encoders seem to have similar hiss problems. I would probably now give LAME 3.98 something like 3.3 - 3.5)
FhG is noisy and has some sandpaper problem too.
Helix is constantly a bit distorded.
iTunes is the cleanest. I didn't notice the problem Pio2001 mentioned. (I still don't, even though I tried)


The bitrates from Sebastian's bitrate table:
CODE
iTunes   LAME 3.98.2   l3enc (Low Anchor)   Fraunhofer   LAME 3.97   Helix
-----------------------------------------------------------------------------
117      149           128                  121          126          110


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Pio2001
post Nov 27 2008, 00:22
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QUOTE (Alex B @ Nov 26 2008, 22:42) *
I didn't notice the problem Pio2001 mentioned. (I still don't, even though I tried)


The first two notes, on the left, from 3" to 6", are affected by artifacts, but oddly enough, the artifacts are audible in the opposite channel !
It is more audible with Lame 3.97, during the first note only. I see what you call "sandpaper". The artifacts in iTunes are not sandpaper, but more common mp3 artifacts, I don't know how to qualify them... they're... mpc-ish !
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