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WavPack Hybrid broken on (Arch?) Linux, non lossless and heavily distorted
skamp
post Jul 5 2012, 18:47
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I tried to encode and decode several different WAV files from CD rips with WavPack (version 4.60.1) in hybrid mode, on Arch Linux, on two different machines (Intel Core i7 and Xeon, x86_64). I always got the same result: the files are heavily distorted (groups of samples repeating themselves), and obviously non lossless. See samples.

I ran the following commands:
CODE
wavpack -b400 -c -m hybrid.wav
wvunpack -m hybrid.wv


wvunpack outputs the following:
CODE
WVUNPACK  Hybrid Lossless Audio Decompressor  Linux Version 4.60.1
Copyright (c) 1998 - 2009 Conifer Software.  All Rights Reserved.

original md5:  e180f2ec2c4c65fd214bc6c4f70c7988        
unpacked md5:  2d5edeb0d3d7ba971282428b77fd41c6        
MD5 signatures should match, but do not!


I tried the win32 binary, which worked fine (lossless result). I don't have another Linux distro installed anywhere to see if this problem is distribution-specific. I also tried three different builds (including one built from source by myself), always with the same result.

This post has been edited by skamp: Jul 5 2012, 18:59


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skamp
post May 25 2013, 10:09
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Group: Developer
Posts: 1454
Joined: 4-May 04
From: France
Member No.: 13875



By the way, this kind of bug calls for generating internal MD5 hashes systematically (wavpack -m). When I create a Wavpack file without that option, and the memcpy() bug applies, and then verify the file's integrity with "wvunpack -v", the result is a false positive (wvunpack reports the file is OK, when it's really not). Same with foobar2000, since it doesn't have an internal hash to work with. I suggest that the MD5 hashing option be made a default, like with FLAC.

FWIW, caudec always uses wavpack's -m parameter (compute and store internal MD5 hash).

This post has been edited by skamp: May 25 2013, 10:22


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Posts in this topic
- skamp   WavPack Hybrid broken on (Arch?) Linux   Jul 5 2012, 18:47
- - plus   I can confirm this bug exists on Debian Wheezy amd...   Jul 5 2012, 19:21
- - 2012   Fellow Archer here. I confirm the bug. I got non-...   Jul 5 2012, 20:28
- - Angenial   The bug itself appears not to be architecture-rela...   Jul 5 2012, 21:08
- - 2012   Good catch Angenial. Using memmove() instead of m...   Jul 5 2012, 21:46
- - lvqcl   Links about memcpy() behaviour: https://bugzilla....   Jul 5 2012, 21:59
|- - Kohlrabi   QUOTE (lvqcl @ Jul 5 2012, 22:59) Links a...   Jul 6 2012, 00:55
- - bryant   Thanks guys! I have checked Angenial's pat...   Jul 5 2012, 22:19
- - bryant   I knew this sounded familiar! http://www.hy...   Jul 5 2012, 23:22
- - skamp   Any ETA on a bugfix release?   Sep 6 2012, 18:03
- - bryant   I guess Iíve sort of dropped the ball on this. I a...   Sep 7 2012, 07:25
|- - Destroid   QUOTE (bryant @ Sep 7 2012, 07:25) ...ití...   Dec 2 2012, 12:57
- - BearcatSandor   I'm a bit stymied as i've been using wavpa...   Dec 2 2012, 10:51
|- - Mr_Rabid_Teddybear   QUOTE (BearcatSandor @ Dec 2 2012, 02:51)...   Dec 5 2012, 01:33
- - BearcatSandor   Thanks for the link to the SVN and instructions. I...   Dec 7 2012, 01:26
|- - bryant   QUOTE (BearcatSandor @ Dec 6 2012, 16:26)...   Dec 8 2012, 19:48
- - BearcatSandor   Bryant, Thanks for asking. It happens when using ...   Dec 8 2012, 22:12
- - bryant   Well, the first thing is do you get the same MD5 m...   Dec 8 2012, 23:03
- - BearcatSandor   Got it! Thanks Bryant and Mr_rabid_teddybear f...   Dec 9 2012, 21:28
- - skamp   I found another bug (still with version 4.60.1, Li...   May 15 2013, 15:06
- - bryant   Thanks, Skamp! Yeah, the 64-bit Linux memcpy(...   May 15 2013, 17:24
- - skamp   OK, cool!   May 15 2013, 18:28
- - skamp   By the way, this kind of bug calls for generating ...   May 25 2013, 10:09
- - bryant   Yeah, the problem with this bug is that the issue ...   May 26 2013, 01:51
- - skamp   Another shameless plug: caudec SVN (upcoming versi...   May 26 2013, 08:28
|- - bryant   QUOTE (skamp @ May 26 2013, 00:28) Since ...   May 29 2013, 07:01
- - skamp   Moreover, when asked to compute MD5 hashes, caudec...   May 29 2013, 11:15


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