title
Products            Buy            Support Forum            Professional            About            Codec Central
 
Results 1 to 6 of 6

Thread: Coverter fidelity

  1. #1

    Join Date
    Apr 2022
    Posts
    5

    Coverter fidelity

    So according to this reply, and theoretically, same "source" files should be the same and have identical hash. I get that and personally, I agree that uncompressed data should always be the same.

    However, when I convert a blank WAV (no metadata) to WAV and uncompressed FLAC, all 3 of them show different hash. Does it mean they are different? If anyone can explain this to me I'm much appreciated.

  2. #2
    Administrator
    Join Date
    Apr 2002
    Posts
    43,855

    Re: Coverter fidelity

    If using windows install the utility codec 'Calculate Audio CRC':

    https://www.dbpoweramp.com/codec-central-utility.htm

    Then convert all 3 files to this codec and a notepad will appear showing the audio CRC for the decoded data, if it matches all 3, then they are identical.

  3. #3
    dBpoweramp Guru
    Join Date
    Nov 2007
    Location
    Florida, USA
    Posts
    5,735

    Re: Coverter fidelity

    As @spoon notes it is important to compare *audio* CRCs. You are likely comparing total file CRCs, and these can differ because of the metadata (non-audio) information in each file.

  4. #4

    Join Date
    Apr 2022
    Posts
    5

    Re: Coverter fidelity

    Thank you, I was looking for something like this. The results are the same.

    However, it's pretty strange cause what might cause my problem in the first place is metadata, but I deleted all of them, so all files are "blank".
    Last edited by haihayho; 04-25-2022 at 10:14 PM.

  5. #5
    Administrator
    Join Date
    Apr 2002
    Posts
    43,855

    Re: Coverter fidelity

    There are headers also in the files.

  6. #6
    dBpoweramp Guru
    Join Date
    Apr 2021
    Posts
    441

    Re: Coverter fidelity

    Expecting the hash of the WAV and FLAC to match is like expecting the hash of a word document and a LibreOffice document to match; even though they may have the same user content they're two completely different formats.

    I don't know enough about the wav format to know why your original wav and the converted wav didn't match, but if you used the same tool and options they should. I converted from a single wav multiple times to wav and flac formats, and all the wav's matched as did all the flac's.

    Flac stores the hash of the decoded audio content internally, so even if you'd made lots of tag changes, or even changed the flac compression level itself, it's trivial to compare/validate that the audio is still the same (by storing the original value somewhere).

    To display the MD5 of the decoded audio data:
    Code:
    metaflac --show-md5sum <filename>
    To verify that the actual audio data still matches the stored hash (to highlight data corruption):
    Code:
    flac -t <filename>

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •