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Thumbnails and media files previews

Feature availability

Available from: 4.2.0
Available for:

  • Windows - Access to files on a Caching Gateway over SMB, using File Explorer.
  • macOS - Access to files on a Caching Gateway over SMB and local folders with TSS (transparent selective sync) enabled.
  • Linux - Access to files on a Caching Gateway over SMB.

With the placeholder preview thumbnails feature, your file manager can present thumbnail previews for placeholder files. This lets you quickly get an idea of the contents of a media file without having to wait for it to be fully downloaded.

When generating file previews, a portion of a file is retrieved. The exact behavior isn't fixed and depends on the file size and format. For smaller files (such as images), the entire file is usually downloaded. For larger media files, different approaches may be applied - in some cases, the whole file is downloaded, while in others only certain segments or metadata are retrieved to enable progressive loading or quick previews.

Enable placeholder preview thumbnails

Windows

To enable placeholder preview thumbnails for SMB shares on Microsoft Windows workstations:

  1. Ensure that if the placeholders_as_regular_files_for_smb_server custom parameter has been added to your Job profile it has 1 assigned to it (which is its default value).

  2. In File Explorer open folder options and make sure the Always show icons, never thumbnails option is disabled.

    Preview Thumbnails View Settings

Thumbnails for placeholder files in file managers

Certain file managers, such as Total Commander, do not support thumbnails for placeholder files. In such cases, the system may need to fully hydrate the file to generate a thumbnail. This can lead to a delay in thumbnail display and might require reloading the contents of the folder.

macOS

Thumbnail previews for placeholder files accessed over SMB are enabled by default.

Thumbnail previews for local placeholder files with the TSS are enabled by default.

In Agents 5.0.9 and older, you can disable previews, by adding the fs_fuse_download_block_list custom parameter to the Agent Profile with the following value: 

Finder.app;QuickLook;com.apple.appkit.xpc.openAndSavePanelService;/usr/libexec/lsd;com.apple.iTunesLibraryService;/System/Library/CoreServices/iconservicesagent;/System/Applications/Music.app/Contents/MacOS/Music;/System/Library/PrivateFrameworks/AMPLibrary.framework/Versions/A/Support/AMPLibraryAgent;/Applications/CleanMyMac X.app;/Applications/Resilio Connect Agent.app/Contents/MacOS/Resilio Connect Agent;/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/Metadata.framework/Versions/A/Support/mds;/System/Library/ExtensionKit/Extensions/ImageThumbnailExtension.appex/Contents/MacOS/ImageThumbnailExtension;/System/Library/ExtensionKit/Extensions/AudiovisualThumbnailExtension.appex/Contents/MacOS/AudiovisualThumbnailExtension;/System/Library/ExtensionKit/Extensions/OfficeThumbnailExtension.appex/Contents/MacOS/OfficeThumbnailExtension

To optimize local storage usage, enable Progressive Hydration by adding the tss_hydration_policy: 0/1 parameter to the Job policy. For details, see File streaming: progressive Hydration in TSS.

Linux

To enable thumbnail previews for placeholder files accessed over SMB, in file manager's preferences, in the Performance section, select the option to show thumbnails for all files.

Preview Thumbnails Linux