Proxies and Thumbnails

by | Oct 21, 2012 | Viewing Media and Metadata |

BROWSE CATDV SUPPORT MANUALS

A clip can have different types of media representation: small thumbnail images, the original movie or media file, and a low-resolution proxy movie. A clip in CatDV contains a reference to its media, not the media itself, so all these types of media can be shared by more than one clip. (This also applies when you create subclips. Subclips refer to parts of a media file, specified by a time offset from the start of the file, and don’t involve creating new files or modifying your original files.)

Thumbnails

  • Thumbnails are stored in the catalog along with the clips (so they remain available even when the media file is offline).
  • Thumbnail images are created when you import a movie or still image into a catalog, typically for the first, last and middle frame of each movie or scene, though there is a Preference option to control how many thumbnails are created (or even to turn off automatic thumbnail generation altogether).
  • You can select the size of thumbnails in Preferences. (Note that larger thumbnails increase the size of catalog files and the time to open them.)
  • Thumbnails are automatically shared. All the thumbnails in a catalog with the same tape name and whose timecode lies between the “in” and “out” point of a clip are available for display with that clip.
  • If you have timecode resets or don’t give each tape a unique name you might see incorrect or jumbled up thumbnails. To avoid this, either fix the tape name or turn off the Automatically link media based on tape name option in Preferences.
  • Use the Build Thumbnails command to rebuild the poster thumbnails of selected clips (after changing the thumbnail size for example). You can also create additional thumbnails, for example one every 10 seconds. Again, please note that creating extra thumbnails increases memory requirements, and the time to save and load the catalog.
  • You can create an additional thumbnail manually, and set that as the poster for a clip, by going to the frame you want in the “movie” tab and pressing the Set Poster button.
  • Conversely, you can delete an unwanted thumbnail using the Delete Thumbnail button. You can also switch to a thumbnail view and delete unwanted “thumbnail clips” there.

Original media

  • The original movie or source media files can be played if they are online, i.e. accessible on the computer’s hard drive or a mounted network volume. Clips can also be offline, if the file was moved or deleted or a removable volume is offline.For example, in tape-based workflows the source media will often be deleted from disk at the end of one project to make space for the next one. (Given the tape name and timecode values you should be able to use batch capture within your NLE software to recapture the original files, without any loss of quality, if they are ever needed again.)
  • Use the Attach Media command if you have recaptured the source media, or to attach a media file to a clip that didn’t previously have one (eg. because the clip definition was imported from an EDL or batch list).
  • Use Update Media Location if you have simply renamed or moved the source media files to a new location. Usually you only need to select the new location for the first file – other files in the same directory are reattached automatically if they still have the same name and file size.
  • Adding the original and new location as equivalent media directories (see below) allows CatDV to locate similarly moved media files automatically without asking you.

Proxies

CatDV supports the use of low-resolutions proxy or preview movies to use if the original media is offline. In a networked environment the online media might only be accessible to the edit suites while desktop computers might use the previews for logging and to decides whether clips are suitable for inclusion in a project.

  • Use the Build Proxy Movies command to build a proxy movie of the selected clips.
  • Proxy movies are stored on disk in a common proxy directory and are shared between catalogs. Once created they are available even when the original source movie is deleted.
  • Specify the directory for proxies and choose their size and quality in CatDV’s Preferences. You can also choose whether to burn in timecode or a watermark image into the proxy file.
  • Tape-based proxy files should be treated as ‘private’ to CatDV but can be exported with Export As Movies if you want to use them in another application.
  • Use Proxy Manager to see which proxy files are available, rename a tape, or delete unwanted proxies. (This command is only available if you enable advanced menus via Preferences.)
  • You can use the original tape-based preview mechanism or newer path-based proxies, or both (see below)
  • You can have more than one proxy directory. The first directory is where new proxies will be created but all the directories are searched in turn when looking for a proxy movie.
  • To create proxy files automatically as part of a complex networked workflow consider using the separate CatDV Worker Node product.

Locating media

CatDV can find the media for a clip in two distinct ways, by tape name or by file path.

Tape-based lookup:

  • If a clip originates from tape and the Tape field is correctly set then using tape-based proxies another clip can automatically use that same media, even if it doesn’t have a direct link to the media file. Together the tape name and timecode uniquely identify the media.
  • If you don’t set a unique tape name (or if you have timecode resets) then you should disable tape-based media linking in Preferences otherwise you might see incorrect thumbnails or proxies for a clip.

Path-based lookup (of original media or low-res proxies):

  • For tapeless workflows, or if you are cataloging existing files on disk, then CatDV will locate media based on a file path. A media file may move, however, or it may have different paths depending on which machine you access the media from (eg. M:ProjectXFile1.mov and /Volumes/Media/ProjectX/File1.mov may be the same file). CatDV therefore uses a search path with file mapping rules to look for any files which it can’t find in their original location.For example, if CatDV knows that M: is mapped to /Volumes/Media then CatDV on a Mac would be able to find the media file even if the catalog was saved on a Windows machine.
  • You can edit path mappings in the Media Search Paths section of Preferences. You should normally enter both the original (what is stored i the catalog) and new location (where the files are now).
  • If you omit the original location CatDV will search every combination of paths for the file. This will generally work but is less efficient and may find erroneous matches. For example, if the file was originally at “/Capture Scratch/Project X/Good Clips/Clip1.mov” and you add “/Volumes/Archive” to the search path then it will search all the following locations in turn:/Volumes/Archive/Capture Scratch/Project X/Good Clips/Clip1.mov
    /Volumes/Archive/Project X/Good Clips/Clip1.mov
    /Volumes/Archive/Good Clips/Clip1.mov
    /Volumes/Archive/Clip1.mov
  • If you try to play a file (using the Play Media command) and it’s offline (not at the location where the catalog says it is), CatDV will prompt you to locate it. If you successfully locate the file at a new location CatDV will offer to add the mapping from old to new location to media search path for you.
  • As well as searching for the original full-resolution media files which may have moved, you can also enable path-based proxy movies. These use the same search path mechanism to map original location to proxy location but unlike with full-quality media the proxies don’t need to have the same size and filename as the original file. For example, you might set “/Volumes/Proxies” as a path-based proxy location and have a proxy file “/Volumes/Proxies/Project X/Good Clips/Clip1.mp4”.

See also: Preferences