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Thread: Accurip detects Corrupted Files, but they play Fine...

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  1. #1

    Join Date
    Mar 2017
    Posts
    8

    Accurip detects Corrupted Files, but they play Fine...

    I am using PerfectTUNES on macOS 10.15.4. I used the Accurip feature and it found 24 FLAC files that are stored on my NAS as corrupt. I tried play a few of these files in VLC and the 3 that I tried play just fine. I tried the same files in AudioStation on my Synology NAS and they played fine there as well. What could cause this?

  2. #2
    dBpoweramp Guru
    Join Date
    Nov 2013
    Location
    New York
    Posts
    356

    Re: Accurip detects Corrupted Files, but they play Fine...

    Inaccurate may not mean "corrupt". The files might have been modified by one of the DSP processes. Did you trim silence from the beginning and or end of rips? That makes the checksum different, therefore it will report it as inaccurate. You presumably wanted to remove the silence, so it sounds fine, just without the silence you didn't want to hear. But it no longer matches the unmodified checksum, it is "inaccurate". Applying volume adjustment (not just tagging the track with a playback volume adjustment, but actually "applying" it also changes the checksum.

    Beyond that, you could have tracks with a few bad frames. They will show up as inaccurate. One frame is 1/75th of a second. And only a few bits of the frame might be bad. You are unlikely to hear such an error. You should use the results of the Perfectunes accuraterip list to tell you which tracks you might want to listen to, so you can decide which ones to ditch (because they are bad enough that you don't want to listen to them) and which ones have no audible impairment or the impairment is slight enough that you don't mind hearing it. There are plenty of things I hear in recordings that could be a human error in performance or production (or an effect the producer wanted) or they could be a reproduction error.

    Most of us of any age listened to records with pops, clicks, hiss, even skips and just accepted that as part of listening. Now people obsess over finding two bad bits out of the entire performance. "Oh, it's not bit perfect" They need to get over it.

    This doesn't mean that the Accuraterip process isn't worthwhile, either when ripping or after the fact to check your files, I'd certainly like to know if a track starts to skip in the middle when I'm ripping it while I can try cleaning it, or ripping in a different drive, or wow, buying another copy on EBay, or even borrowing it from the library to rip their copy. And if all else fails, I can simply erase the file if it is bad enough I don't want to hear it again. And I'd like to know if suddenly several tracks on my hard drive won't play because of data errors (You do keep a backup, don't you?)

    So, yes, 24 tracks out of how many? Were they ever "bit perfect"? If they sound OK, just keep a note of which ones, so when you check them again, you'll know those were already not "bit perfect". If they are bad enough, you have to figure out whether to replace them or ditch them.

    And yes, there can be files that are "corrupt" Many won't play at all, but there can be corruption that messes up the metadata, not the audio, so the accuraterip check can't determine what the file is, and can't look it up in the database, yet the actual audio plays "bit perfect"

  3. #3

    Join Date
    Mar 2017
    Posts
    8

    Re: Accurip detects Corrupted Files, but they play Fine...

    That makes sense. I seem to recall that the few I have checked so far dBpoweramp had to re-rip some frames. So, that may be the issue.

  4. #4

    Re: Accurip detects Corrupted Files, but they play Fine...

    This is of recent interest to me. I've been trying to clean up my collection with the help of PerfectTUNES. My collection is in good shape but there are exceptions. I've even gone as far as buying downloads of some corrupted songs from Quboz. In general, this solves the corruption problem. However, on a couple, even the new downloads show as corrupted. This seems unlikely. I've experiment with a couple scans: keep the download unedited (metadata and album art), edit the download by changing the filename (to match the naming standard of the other songs in the album) and editing the metadata and adding album art. The unedited song scans without error; however, the edited song file scans with a corruption error. Again, only changing the file name (not extension) and editing the metadata. It's not a huge issue but does make me wonder what's going on.

  5. #5
    Administrator
    Join Date
    Apr 2002
    Posts
    40,393

    Re: Accurip detects Corrupted Files, but they play Fine...

    How are you editing the metadata? What are the files? FLAC?

  6. #6

    Re: Accurip detects Corrupted Files, but they play Fine...

    Using dbpoweramp to edit the metadata (access through the windows shell). All the files are FLAC. Oh ya, I have cleared the cache and not in PerfectTUNES. Makes no difference. Also tried deleting the txt file that exists in the album folder from the original dbpoweramp CD rip.
    Last edited by Dale Johnson; 05-01-2020 at 09:26 AM.

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