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Folder based MP3 Comparison?

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  • Folder based MP3 Comparison?

    Is there a way to compare folders containing MP3's based on the tag information? I can't seem to figure it out. The MP3 compare feature seems to only let you compare 2 files at a time. I like to compare entire folder structures like a normal file based comparison but against the tag info.

    For example I have multiple large partial copies of my music library with duplicates and poorly named files and what not. I'm looking for a way to do some bulk merging based on the tags.



  • #2

    Our default comparison run on the Folder level uses timestamp and size, but this can be configured to run a full Rules-based comparison automatically (as if you double clicked on all of your files.)

    Here is a KB article that goes into more detail:
    Aaron P Scooter Software


    • #3
      I have two indentically-structured trees of MP3's:
      1. Well-tagged, but possibly corrupt audio
      2. Poorly-tagged, no corrupt audio

      I want to compare these, ignoring tag data, only considering a comparison of audio data. In the rule set for MP3's, if I untick all checkboxes except Audio Data, will that audio comparison simply be size-based or will it be a binary comparison?

      Also - is there a way to have BeyondCompare consider FLAC files the same as MP3's?


      • #4

        In the latest release of BC3 (currently 3.2.4), if you untick all the checkboxes except the Audio Data in the session settings or default session settings, it shows the size statistic but runs a binary compare on that section (non-tag) area. If it shows as equal, then that section of the file is binary equal.
        Aaron P Scooter Software


        • #5
          Much thanks, Aaron, I'll go buy my license right now.

          FLAC and other codecs are a nogo?


          • #6
            Do I have these settings correct?

            Here are my file compare settings.
            Here are my MP3 compare settings.

            I read the KB article from above (several times, actually) and I'm not quite certain the difference between Quick Compare and Rules-Based Compare. Also I'm unsure if I want to override Quick Test Results in the Folder Compare, but I think I do.

            From my requirements in the post above, will these settings get me what I want?

            Also, for the binary compare of audio data, what if there's a byte that's different between the two files? Their sizes will be the same, but contents won't. Will BC highlight the identical file sizes as red in the MP3 view with differing content?


            • #7

              First, if you want this to always apply, it will need to be set as the Session defaults (as one of your pictures shows the dropdown, but was it applied?)

              Alternatively, you can save a specific Folder Compare session with specific child settings using the same dropdown control in the child session's session settings.

              You will probably want to enable both Timestamp and File Size, and Rules-based and Override Quick Test results.

              The Rules-based results, which will be used and override the Timestamp/size comparison, will compare only the section of data that is not in the Tag area of your MP3 files. This is a binary scan of this section, so a byte difference would still be picked up. If your files are corrupted outside this area it is possible for them to show as Equal while having a corrupted section. If you need a full scan, you can use a Binary scan instead of a Rules-based. This would scan the entire file and would pick up on any changes, but would include marking a file as different if there are *any* changes, including tags.

              By leaving Timestamp/Size enabled, it will show this information in the comparison and allow files to be "newer" or "older" rather than just "different."

              Does that help clear up how the different settings are used?
              Aaron P Scooter Software


              • #8
                Right - I had already set those values as defaults for the Session Settings so I should be good there.

                I still have a couple questions.

                I'm not understanding what good it does to Compare file size and Compare timestamps. If these are identical, how does the comparison progress differently than if they're different? That is:
                Compare date/size (SAME) --> Now what? Move on to next files?
                Compare date/size (DIFFERENT) --> Now we go to Rules-based comparison?

                If I tick the box to override quick test results, then what good have the quick test results provided?

                What is the context of the rules-based comparison? Is that a rule-set based on the current session type (Folder Compare) or a rule-set based on the current file being compared (MP3's)? Presumably this is the latter and Beyond Compare simply knows that when it's comparing MP3's to use the rule-set from the session settings of MP3's.

                Last question. When I'm looking at an MP3 comparison, I notice that differences in the numeral of the Data area size are highlighted in blue/red. If the Data area of the MP3's are identical in size (same number), but the Data area contains differences, how will BC communicate this to me? Will the numbers both be highlighted in BLACK (indicating equal) and yet I'll see the red unequal symbol in the Folder Compare session?


                • #9

                  Running the Filesize/Timestamp and Rules-based comparison with Override Quick Test results does not change the results, but gives the files additional status. For example, if you perform a Sync:Update command on a selection of files, this command copies Newer and Orphan files. But if you have disabled timestamp comparison, then we do not copy any of your Different files; the timestamp is still shown in the interface but since it has been disabled for comparison purposes it has been set to not be used.

                  With Rules-based comparison enabled and Override Quick Test results enabled, a rules-based comparison will be run on each file and that comparison status is used to determine if the file is equal or different. A rules-based comparison is like double clicking every file, and passing back that child session's comparison value to the parent session. This uses the default settings, so the topmost File Format in the Tools menu -> File Format's list is used to control which session type is used; for MP3's this defaults to the MP3 Compare session type. You have already set the default settings used by a new MP3 Compare session. Does that help explain how the Rules-based comparison works?

                  This is potentially configurable. You can open a child session manually, set different settings, and then pass only those settings back to the parent folder comparison (for just those files or all files). But by default it will use the global defaults.

                  For the last question, it should show as red. We show a numerical size as a representation of the Data, but it is running and returning a binary scan on that section. The Folder Compare would populate the center column between files as Equal (black) or Different (Red) equal sign, and the Display Filters set to show different files would show these files. Are you encountering different behavior?
                  Aaron P Scooter Software


                  • #10
                    I think I've finally got it. Check my understanding.

                    When I tick the box for Rules-based comparison (and uncheck Skip if quick test shows files same...) I'm specifying that, for the file type being analyzed, use the default session settings for comparison of the files.

                    Ticking Override quick test results is basically the same as unticking all boxes in the Quick tests section - it means that BC won't consider Quick tests as a component of whether the files are different or not. So I could sync older files over newer files and BC won't complain in this situation.

                    I did run into several situations where MP3's had different Data areas that were the same size and, you were right, they were highlighted in red.

                    How do I open a child session to change, for instance, MP3 rules from a current session?
                    I did run into what I think is a bug. The rules for MP3 comparison would sometimes be different for files that I double clicked. I would compare thousands of files the rules would work fine. Then I'd double click an MP3 and two to five random attributes would also be ticked for comparison. It made me feel uneasy that the comparisons were completely accurate although the Data area was always ticked and this was my primary concern. So the worst that could happen was that files were highligheted as different that actually weren't (false positive), which was fine.

                    Let me know if I have things straight and thanks very much for your help, Aaron.


                    • #11

                      Close. Override Quick Test results will mark a file as different, even if the timestamp and size are equal, and will mark the file as equal even if the timestamp is different. However, if the content comparison is different and the timestamp is different, then the file will be "Newer" or "Older" for its status. A status of "Different" will only occur if the content comparison returns different, and the timestamps are equal. A Sync Update will still only deal with "Newer" files or Orphan files, and won't copy over "Older" or "Different" files.

                      You can find a complete list of tags on the Home screen (first screen BC3 shows when booted). In the Saved Sessions list of auto-saved and manual sessions, there is a green Edit session defaults folder. Expand this and select MP3 Compare to find the list to uncheck. The lists shown in the specific MP3 Compare child sessions would only be those tags that apply to that pair of files.

                      Setting a child sessions settings involves opening the parent folder compare, double clicking a file, editing the session settings of that file's comparison, and changing the dropdown from "use for this view only" to "Use for all files in parent session" and then re-saving the parent Folder Compare.
                      Aaron P Scooter Software