INTERACT FORUM

More => Old Versions => Media Center 15 (Development Ended) => Topic started by: Von on March 03, 2011, 04:22:53 pm

Title: Two secure rips, different results?
Post by: Von on March 03, 2011, 04:22:53 pm

I ripped the same album to wav twice in secure mode. Did an md5 check, and tracks 2 and 4 showed differences. Track 4 is understandable, as for both rips the log says 1% of sectors could not be verified, and there are several positions with unreliable data. (Same positions in both rips, actually, but I guess that doesn't mean they can't be different.)

However, track 2 should be fine, as the logs say:

First rip:
Track  2: Secure rip, no re-tries. [Track 02]

Second rip:
Track  2: Secure rip, 1% of sectors needed re-reading. [Track 02]
      00:03:21  3 re-reads required to get good data
      00:03:39  2 re-reads required to get good data

Shouldn't these files be identical?

Title: Re: Two secure rips, different results?
Post by: MrC on March 03, 2011, 04:32:12 pm

Did you do an md5 sum on the *file* or just the actual music portion of the music file?  The files will a number of differences.

Title: Re: Two secure rips, different results?
Post by: Von on March 03, 2011, 04:44:42 pm

Quote from: MrC on March 03, 2011, 04:32:12 pm

Did you do an md5 sum on the *file* or just the actual music portion of the music file?  The files will a number of differences.

On the file. I have always done this, and it works fine on wav files. At least with the classic program mkwACT that I use. Also note that the four other tracks on the album match.

Title: Re: Two secure rips, different results?
Post by: Alex B on March 03, 2011, 05:04:16 pm

As MrC said, the correct way would be to compare only the audio content. MC does not have built-in tool for that. Many advanced audio editors can do a "copy > invert mix paste" operation. If the resulting file is nulled (aka completely silent) then the files are identical. Foobar2000 has a bit compare tool that can do the same. Actually, if I recall correctly, also EAC has a "compare wavs" tool for that.

In this case the file headers should probably be identical (assuming wave tagging is disabled or absolutely no changes to the tags were applied). It is possible that MC got exactly the same incorrect data twice and thus the rip was detected as secure.

You should carefully listen to the passage from 3:15 to 3:45. If the files don't produce any audible errors (clicks , pops, stuttering, etc) they are good enough.

Title: Re: Two secure rips, different results?
Post by: DarkPenguin on March 03, 2011, 06:49:13 pm

Doesn't secure ripping just mean that MC got the same data two reads in a row?