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Topic: iTunes Plus vs. FLAC (Read 10689 times) previous topic - next topic
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iTunes Plus vs. FLAC

This one was a lot tougher.

foo_abx 1.3.4 report
foobar2000 v1.3.2
2014/06/19 15:08:55

File A: [Omitted] Tower of Song.flac
File B: [Omitted] Tower of Song.m4a

15:08:55 : Test started.
15:13:38 : 00/01  100.0%
15:24:33 : 00/02  100.0%
15:56:03 : 01/03  87.5%
16:02:14 : 02/04  68.8%
16:05:57 : 02/05  81.3%
16:11:15 : 03/06  65.6%
16:11:43 : 04/07  50.0%
16:12:39 : 05/08  36.3%
16:13:43 : 06/09  25.4%
16:15:15 : 07/10  17.2%
16:21:41 : 08/11  11.3%
16:24:43 : 08/12  19.4%
16:25:38 : 09/13  13.3%
16:27:12 : 09/14  21.2%
16:31:20 : 10/15  15.1%
16:32:05 : 10/16  22.7%
16:32:43 : 10/17  31.5%
16:34:27 : 11/18  24.0%
16:35:23 : 12/19  18.0%
16:36:21 : 12/20  25.2%
16:39:10 : 13/21  19.2%
16:39:42 : 14/22  14.3%
16:41:09 : 14/23  20.2%
16:42:25 : 15/24  15.4%
16:43:52 : 15/25  21.2%
16:45:16 : 16/26  16.3%
16:51:01 : 17/27  12.4%
17:04:29 : 17/28  17.2%
17:05:26 : 17/29  22.9%
17:06:33 : 18/30  18.1%
17:07:27 : 19/31  14.1%
17:08:18 : 19/32  18.9%
17:09:37 : 20/33  14.8%
17:09:56 : Test finished.

----------
Total: 20/33 (14.8%)

Here is the sample:

http://www.hydrogenaud.io/forums/index.php?showtopic=106074

iTunes Plus vs. FLAC

Reply #1 –
Yeah, iTunes Plus should be quite difficult - if not impossible - to distinguish from the lossless source.

That said, may I ask, why did you make this test?

iTunes Plus vs. FLAC

Reply #2 –
Quote from: TomasPin on
Yeah, iTunes Plus should be quite difficult - if not impossible - to distinguish from the lossless source.

That said, may I ask, why did you make this test?


That's a strange question.  To know the answer?

iTunes Plus vs. FLAC

Reply #3 –
Quote from: theriverlethe on
Total: 20/33 (14.8%)


Did you actually decide to do 33 trials before starting the test?  Its important that you not just keep extending the test until the numbers look good, otherwise you'll find that you can sometimes ABX all identical files.  Instead, you should pick a reasonable number (e.g. 10 trials) and then if at 10 you don't have it, start over with a new test using more trials (e.g 20 rounds). 

iTunes Plus vs. FLAC

Reply #4 –
Quote from: saratoga on
Quote from: theriverlethe on
Total: 20/33 (14.8%)


Did you actually decide to do 33 trials before starting the test?  Its important that you not just keep extending the test until the numbers look good, otherwise you'll find that you can sometimes ABX all identical files.  Instead, you should pick a reasonable number (e.g. 10 trials) and then if at 10 you don't have it, start over with a new test using more trials (e.g 20 rounds).


No, I was expecting the probability to revert closer to 50% as I did more trials.

iTunes Plus vs. FLAC

Reply #5 –
Quote from: saratoga on
Quote from: theriverlethe on
Total: 20/33 (14.8%)


Did you actually decide to do 33 trials before starting the test?  Its important that you not just keep extending the test until the numbers look good, otherwise you'll find that you can sometimes ABX all identical files.  Instead, you should pick a reasonable number (e.g. 10 trials) and then if at 10 you don't have it, start over with a new test using more trials (e.g 20 rounds).


I just did three sets of 33 guesses and got ~ 75%, 66%, and 50%.

Edit: Okay, I did one more set and got an 8.1%.  What would you consider a statistically significant result?

iTunes Plus vs. FLAC

Reply #7 –
Haha...

So, I would've needed 22.24 correct for a "pass?"