IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Distortions in AAC file purchased on iTunes
msvadi
post May 21 2012, 03:13
Post #1





Group: Members
Posts: 4
Joined: 21-May 12
Member No.: 100024



Hi all,

I've noticed a couple of audible distortions in an AAC track I bought on iTunes. I uploaded a small fragment of the track with distortions here: 53 FRAGMENT Sonata in A Minor, D. 821, 'Arpeggione '_ I. Allegro moderato.m4a. I wonder if these are compression artifacts or they were caused by something else?

I appreciate your help with this.
Go to the top of the page
+Quote Post
eahm
post May 21 2012, 03:46
Post #2





Group: Members
Posts: 884
Joined: 11-February 12
Member No.: 97076



"Our service is currently unavailable in your country.
Sorry about that."

This post has been edited by eahm: May 21 2012, 03:46
Go to the top of the page
+Quote Post
msvadi
post May 21 2012, 04:19
Post #3





Group: Members
Posts: 4
Joined: 21-May 12
Member No.: 100024



QUOTE (eahm @ May 20 2012, 19:46) *
"Our service is currently unavailable in your country.
Sorry about that."



Sorry about that. I uploaded the same fragment also to Mediafire. I think it should work in the US too:

http://www.mediafire.com/?l8lip63v28y7r1c
Go to the top of the page
+Quote Post
eahm
post May 21 2012, 06:52
Post #4





Group: Members
Posts: 884
Joined: 11-February 12
Member No.: 97076



It seems an audio problem but I am not expert enough of that particular track and I can't for sure say it's not a key vibration sound.

This post has been edited by eahm: May 21 2012, 06:52
Go to the top of the page
+Quote Post
Nessuno
post May 21 2012, 08:30
Post #5





Group: Members
Posts: 422
Joined: 16-December 10
From: Palermo
Member No.: 86562



Of course the only way to be sure would be a comparison with the lossless version, but to me it doesn't seem a compression artefact. It seems more an imperfection in the recording, or some kind of "mechanical" noise from the bow strokes, maybe the microphones were placed a little too near.

In my experience, trying to spot artefacts to ABX on AAC @256Kbps has instead leaded me to find a lot of similar imperfections in the original recordings!


--------------------
... I live by long distance.
Go to the top of the page
+Quote Post
msvadi
post May 21 2012, 17:02
Post #6





Group: Members
Posts: 4
Joined: 21-May 12
Member No.: 100024



I see. Thanks for your replies!
Go to the top of the page
+Quote Post
Wombat
post May 21 2012, 19:08
Post #7





Group: Members
Posts: 950
Joined: 7-October 01
Member No.: 235



To me it simply sounds like a string loosened on the Cello or whatever the bigger stringed instrument is.
Go to the top of the page
+Quote Post
eahm
post May 21 2012, 20:42
Post #8





Group: Members
Posts: 884
Joined: 11-February 12
Member No.: 97076



The original one has the same sound as well, as I supposed it's just a key vibration sound.

http://dropcanvas.com/pnvin

EAC Log:
CODE
Exact Audio Copy V0.99 prebeta 5 from 4. May 2009

EAC extraction logfile from 6. January 2011, 1:50

Andras Schiff, Yuuko Shiokawa, Miklos Perenyi / Andras Schiff - Concertos & Chamber  Music - CD7 - Schubert

Used drive  : HL-DT-STDVDRAM GSA-4083N   Adapter: 1  ID: 0

Read mode               : Secure
Utilize accurate stream : Yes
Defeat audio cache      : Yes
Make use of C2 pointers : No

Read offset correction                      : 667
Overread into Lead-In and Lead-Out          : No
Fill up missing offset samples with silence : Yes
Delete leading and trailing silent blocks   : No
Null samples used in CRC calculations       : No
Used interface                              : Native Win32 interface for Win NT & 2000

Used output format              : User Defined Encoder
Selected bitrate                : 768 kBit/s
Quality                         : High
Add ID3 tag                     : No
Command line compressor         : C:\Program Files\Exact Audio Copy\FLAC\FLAC.EXE
Additional command line options : -6 -V -T "ARTIST=%a" -T "TITLE=%t" -T "ALBUM=%g" -T "DATE=%y" -T "TRACKNUMBER=%n" -T "GENRE=%m" -T "COMMENT=%e" %s -o %d


TOC of the extracted CD

     Track |   Start  |  Length  | Start sector | End sector
    ---------------------------------------------------------
        1  |  0:00.00 | 11:19.55 |         0    |    50979  
        2  | 11:19.55 |  4:18.52 |     50980    |    70381  
        3  | 15:38.32 |  9:15.08 |     70382    |   112014  
        4  | 24:53.40 | 15:07.15 |    112015    |   180054  
        5  | 40:00.55 |  9:56.65 |    180055    |   224819  
        6  | 49:57.45 |  6:40.05 |    224820    |   254824  
        7  | 56:37.50 |  9:04.25 |    254825    |   295649  


Range status and errors

Selected range

     Filename F:\Music\Schiff - Concertos & Chamber Music\Schiff - Concertos & Chamber  Music - CD7.wav

     Peak level 98.8 %
     Range quality 100.0 %
     Copy CRC CC05314A
     Copy OK

No errors occurred

End of status report


This post has been edited by eahm: May 21 2012, 20:58
Go to the top of the page
+Quote Post
msvadi
post May 21 2012, 21:15
Post #9





Group: Members
Posts: 4
Joined: 21-May 12
Member No.: 100024



QUOTE (eahm @ May 21 2012, 12:42) *
The original one has the same sound as well, as I supposed it's just a key vibration sound.


Thank you very much! This is very helpful. I was considering contacting iTunes and asking them to fix the issue. Now I see that it's not their fault.
Go to the top of the page
+Quote Post
Kees de Visser
post May 21 2012, 22:47
Post #10





Group: Members
Posts: 617
Joined: 22-May 05
From: France
Member No.: 22220



QUOTE (Wombat @ May 21 2012, 20:08) *
To me it simply sounds like a string loosened on the Cello or whatever the bigger stringed instrument is.
Agreed. It's Miklos Perenyi playing the cello. A great artist.
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 20th April 2014 - 17:54