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Thread: Mezzmo: Display of existing video thumbnails broke after backup restore on new system

  1. #1

    Exclamation Display of existing video thumbnails broke after backup restore on new system

    Hello,

    I had to reinstall my Windows 10 a couple days ago and restored my Mezzmo Pro Library via a recent backup created by the app.
    But no video thumbnails of my media library are shown anymore (in the Mezzmo App, as well on any connected DLNA device).
    The only images shown in the Mezzmo App are folder backrounds (...\Artwork\Backdrop).

    If I add new video files to the folders the library is scanning, Mezzmo is generating proper file thumbnails as it always did. But existing files are still shown without there previews.
    "Missing" thumbnails are also not getting updated when I visit the folder in the app, where the video file is located, because the thumbnails in fact exist, they simply don't get displayed (...\Artwork\Poster is filled with 10k's of images)

    What I have tried so far:
    • Selected delete cover image in some affected file properties, to force generating new ones
    • Started Maintain Library and let it run for 2 days till it sorts of got stuck and only produced TBs of network traffic doing nothing useful (see below)
    • Deleted VideoPreview.dll and Artwork folder, another library maintenance (got stuck at around 4k previews of around 22k files doing nothing for the rest of the day, aborted and restored from backup again)
    • Set access rights of Mezzmo Library folder to user “anyone”
    • Running Mezzmo as windows process (w/o admin credentials)
    • Run Mezzmo App as admin

    How can I get the thumbnails of my existing video-files showing up again?

    BTW: Why does the maintenance process takes multiple days (back on the old system where all was working, no preview updates selected) when the files are stored on a Synology NAS connected via Gigabit Ethernet?
    Last edited by PixelAviator; 07-06-2018 at 10:52 AM.

  2. #2
    Join Date
    Sep 2009
    Posts
    1,646

    Default

    Hi,
    we had another user with a similar problem, did the path to the Mezzmo database change when you restored your backup? The path to the posters is stored in the database and gets updated when you move your Mezzmo database but if you restore it to a location different to the previous location then the path to the posters will not be correct. You can view this using SQLite Spy or another sqlite viewer and run an sql query to update it or use the Maintenance tools in Mezzmo to search and replace for the path and update it.

    Mezzmo Android: Install it on your tablet, smartphone, Android TV or Amazon Fire to browse and stream files from your Mezzmo library to all your devices. Full details at http://www.conceiva.com/products/mez...mo_android.asp
    Mezzmo for Kodi Add-on: Install it into Kodi to stream files from your Mezzmo library directly in Kodi. Full details at http://www.mezzmo.com/wiki/doku.php?...odi_user_guide
    Mezzmo for Roku App: Install it onto your Roku to stream files from your Mezzmo library. Full details at http://www.mezzmo.com/wiki/doku.php?...oku_user_guide
    Wiki: User Guides & Reference Manual at http://www.mezzmo.com/wiki
    Facebook: http://www.facebook.com/Mezzmo.DLNA.Server
    Twitter: https://twitter.com/conceiva_mezzmo
    Web: http://www.mezzmo.com

  3. #3

    Default

    That is indeed the case. The Mezzmo Database was stored on "E:\Mezzmo Database" on the old Windows installation.
    I restored this backup to "I:\Mezzmo\Database" onto an SSD-drive to boost the database access time.

    The maintainance tools in Mezzmo only work for media files stored in the Mezzmo Database itself. They don't seem to alter internal database entries of absolute paths.

    So if I understood you correctly, I need to do the following:

    1. restore a backup to the old path "E:\Mezzmo Database"
    2. Use the move database feature inside the Mezzmo App to move the whole database to the new path of "I:\Mezzmo\Database"

    So this will also update the absolut path for the thumbnails stored in the SQLLite-DB from "E:\Mezzmo Database\Artwork\Poster\..." to the new path "I:\Mezzmo\Database\Artwork\Poster\..."?

  4. #4
    Join Date
    Sep 2009
    Posts
    1,646

    Default

    Yes this is correct, if you can restore it to E:\Mezzmo Database the thumbnails will show up correctly then you can move the database using the Options in Mezzmo to I:\Mezzmo\Database

    Mezzmo Android: Install it on your tablet, smartphone, Android TV or Amazon Fire to browse and stream files from your Mezzmo library to all your devices. Full details at http://www.conceiva.com/products/mez...mo_android.asp
    Mezzmo for Kodi Add-on: Install it into Kodi to stream files from your Mezzmo library directly in Kodi. Full details at http://www.mezzmo.com/wiki/doku.php?...odi_user_guide
    Mezzmo for Roku App: Install it onto your Roku to stream files from your Mezzmo library. Full details at http://www.mezzmo.com/wiki/doku.php?...oku_user_guide
    Wiki: User Guides & Reference Manual at http://www.mezzmo.com/wiki
    Facebook: http://www.facebook.com/Mezzmo.DLNA.Server
    Twitter: https://twitter.com/conceiva_mezzmo
    Web: http://www.mezzmo.com

  5. #5

    Default

    Ok, so did what you recommended. The thumbnails still not showed up after transferring the database using the Mezzmo tools from the old to the new path. Only Backdrops worked, as before.

    It's getting technical now:

    So I looked into "Mezzmo.db" with "SQLLite Spy" and found out that, TABLE MGOBackdrop was updated correctly with the correct paths.

    On the other hand, TABLE MGOPoster had only updated the last row (highest ID) with the correct paths, all other rows had the old path

    So, I executed the following SQL statement to fix the other rows:
    Code:
    UPDATE MGOPoster
    SET Path = REPLACE(Path, 'E:\Mezzmo Database\', 'I:\Mezzmo\Database\')
    WHERE Path LIKE ('E:\Mezzmo Database\%')
    This updated only the first around 10k entries, then it stopped with an SQL 19 Error - a UNIQUE Constraint violation of the tables INDEX:
    Code:
    CREATE UNIQUE INDEX Index_MGOPoster ON MGOPoster (Path);
    DROP'ing the INDEX fixed that, but the INDEX could not get created again because of the still violated constraint. Also I don't know how the Mezzmo DB would handle that, my last SQL sessions during my study are to long ago and I don't work on the low end level of databases very often now. So, I restored the backup of the "Mezzmo.db" and did another approach.

    I DELETED only the ROW with the one correct path (with the last/highest ID) and executed the SQL statement to fix the paths again and it run through without the error.

    Now the Thumbnails seem to work as they should.

    So it looks like the Mezzmo tools that change the database paths during your migration process created an inconsistent state of the TABLE MGOPoster, that resulted in this operation getting aborted.

    Another question:
    I also noticed there is a huge amount of old database entries containing old file paths to files that no longer exist. These are basically files that have been moved from local disks to the NAS, all using the Mezzmo tool to fix the path inside the app after they have been copied to the NAS. That only worked half way, because a lot of files where considered as new when starting the maintenance library process.

    Therefore, there is also a huge number of unused images for these files in the ".../Artwork/..."-folder. It’s now almost 25 GB huge and probably only 1/4 of this is still relevant.

    Is there a maintenance option in Mezzmo to get rid of all these abandoned data?

    Selecting the option "remove files not found during the maintenance process" seems not to remove these old entries and artwork form the DB so its growing over time. No wonder the maintenance process takes days to complete.

    Compressing the DB with the Mezzmo Tools did nothing but give me 86 MB less from a normaly 2 GB "Mezzmo.db". Also zero change to the mentioned abandoned database entries and the obsolete thumbnails in the Artwork-folder.
    Last edited by PixelAviator; 07-07-2018 at 05:04 AM.

  6. #6
    Join Date
    Sep 2009
    Posts
    1,646

    Default

    If you run Maintain Library from the toolbar or the menu with the option to remove files that cannot be found on disk selected it will remove the files. Right-clicking on a folder and Maintaining the folder will not remove the files with the option to remove files that cannot be found on disk selected because when maintaining a folder Mezzmo just gets the list of files in the folder and any files that do not exist are not processed.

    Mezzmo Android: Install it on your tablet, smartphone, Android TV or Amazon Fire to browse and stream files from your Mezzmo library to all your devices. Full details at http://www.conceiva.com/products/mez...mo_android.asp
    Mezzmo for Kodi Add-on: Install it into Kodi to stream files from your Mezzmo library directly in Kodi. Full details at http://www.mezzmo.com/wiki/doku.php?...odi_user_guide
    Mezzmo for Roku App: Install it onto your Roku to stream files from your Mezzmo library. Full details at http://www.mezzmo.com/wiki/doku.php?...oku_user_guide
    Wiki: User Guides & Reference Manual at http://www.mezzmo.com/wiki
    Facebook: http://www.facebook.com/Mezzmo.DLNA.Server
    Twitter: https://twitter.com/conceiva_mezzmo
    Web: http://www.mezzmo.com

  7. #7

    Default

    Yes, I did run several Maintenance processes and they removed deleted files from Mezzmo (Frontend). But what stays is the artwork found in “…\Artwork\Backdrop” and “…Artwork\Poster”. They are also kept in the database. Please see the following screenshot:

    Mezzmo DB.png

    This is one example file from my Mezzmo DB. There are two references for the artworks “Poster” and “Backdrop”. As you can see, there are two files with the same name, but different paths. “disk-e” was the old path on the pc. “disk—192-168-2-108” is the new path on the NAS. The file with the path “disk-e” is no longer in the Mezzmo DB, but it’s artwork is still stored in the database but is not used, as you can see in the last part of the image. Despite of the fact, that the [Poster/Backdrop]-ID is no longer linked to a file of MGOFile, Mezzmo is not deleting the file.

    Add this up to a huge database where you moved almost all files to a new location (NAS), sometimes even multiple times before I had the NAS. You generate a lot of garbage that is bloating up the Artwork-Folder with no longer used posters and thumbnails. They don’t get deleted, because there are still managed by the Mezzmo DB, despite the fact not being referenced to an actual file.

    All I am asking for, is to please add a fix to the maintenance process, that deletes dead artwork entries in MGOFile and therefor also deletes the no longer managed images.

  8. #8
    Join Date
    Sep 2009
    Posts
    1,646

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    Mezzmo re-uses poster and backdrop files for multiple files, so if you have two files in the database that use the same backdrop and poster then Mezzmo will not delete the artwork until both files are removed from the library. This saves space where you have multiple episodes of a series they will use the same artwork.

    Mezzmo Android: Install it on your tablet, smartphone, Android TV or Amazon Fire to browse and stream files from your Mezzmo library to all your devices. Full details at http://www.conceiva.com/products/mez...mo_android.asp
    Mezzmo for Kodi Add-on: Install it into Kodi to stream files from your Mezzmo library directly in Kodi. Full details at http://www.mezzmo.com/wiki/doku.php?...odi_user_guide
    Mezzmo for Roku App: Install it onto your Roku to stream files from your Mezzmo library. Full details at http://www.mezzmo.com/wiki/doku.php?...oku_user_guide
    Wiki: User Guides & Reference Manual at http://www.mezzmo.com/wiki
    Facebook: http://www.facebook.com/Mezzmo.DLNA.Server
    Twitter: https://twitter.com/conceiva_mezzmo
    Web: http://www.mezzmo.com

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