Unity MediaNet is Avid's industrial-strength media-sharing system. It employs a Windows NT server to allow up to 25 users to connect to the same media over Fibre Channel connections. Available for Media Composer systems on both Macintosh and Windows NT platforms, it offers a wide selection of storage options, enhanced security and protection features, as well as many customization options and represents a significant improvement over older MediaShare systems.

Overview

MediaNet consists of a Windows NT server, Fibre Channel drives, a Fibre Channel network, and administration software running on the server. (Unity LANShare, Avid's low-cost

Figure 1. The Administration Tool uses tabs to pack a lot of functionality into a single window.
The Workspace tab allows you to create, delete or modify workspaces.

alternative, uses the same software but is based on Ethernet connections and serves fewer users at offline resolutions only.) Physical drives are combined to create a "drive set," which consists of an administration drive (not needed in Unity Version 2), all media drives and, if needed, spare drives. The media drives are divided into striped "allocation groups," which are then organized into resizable virtual partitions called "workspaces." These workspaces make the Unity storage architecture different from many other Fibre Channel implementations, which use fixed, physical partitions.

The system is primarily administered through three software programs: the Setup Manager, the Administration Tool and the Monitor Tool. All are easy to use but require a basic knowledge of the Windows NT operating system.

Figure 2. The User tab allows you to create and modify access privileges.

The Setup Manager is used for the initial organization of raw drives into a drive set with allocation groups. It can also be used to add or remove drives from allocation groups, as well as to repair damaged drives. The Administration Tool is used primarily to create, manage and grant user access to workspaces (Figures 1 and 2). It also enables you to identify drive sets and allocation groups, which are otherwise invisible. The Monitor Tool (Figure 3) provides users with technical information about Unity status and data stability and can alert the tech support staff via e-mail of file or drive errors. Problems can then be diagnosed and data on failing drives can be relocated, as needed.

Figure 3. The Monitor Tool displays status information.

Users connect to Unity via their platform's network software -- the Chooser on the Mac OS, or Network Neighborhood on Windows NT. Password protection then allows authorized users to access Unity workspaces and mount them onto their desktops.

Allocation Groups

Unity achieves the flexibility of virtual workspaces using what's called a "server assisted architecture," with the Windows NT machine handling allocation issues. This makes it convenient to use, but like other systems that stripe video across several disks, it means that a single drive failure can result in loss of data over an entire allocation group, affecting several workspaces.

Users more comfortable with actual, physical partitions may fear losing media in the ether of
"virtual" workspaces. However, should a drive fail, Unity's Administration Tool makes it easy to identify which media files have been lost. Each allocation group and its corresponding workspaces can be matched to physical drives with the Allocation Groups tab in the Administration Tool.

Workspaces

Because workspaces are virtual, their number and size can be changed at any time. As a result, it is not necessary to create all your workspaces at the beginning of a show. Nevertheless, it's important to devise a scheme for organizing your storage.

It's advisable to have separate workspaces for timecode and non-timecode sources -- this gives you the option of backing up only the non-timecoded material. It's also a good idea to isolate audio files. This will make it easier to offer audio-only access privileges to the sound department or to duplicate audio media for turn-over.

A basic set-up might include the following workspaces:

  • Dailies Picture -- Digitized picture from timecode sources.

  • Dailies Audio -- Digitized audio from timecode sources.

  • Non-timecode Picture -- VHS tapes, still images, animation files, and so on.

  • Non-timecode Audio -- Temp CD audio, etc.

  • Renders

  • Backups -- Bins, sequences and so on.

Unlike other sharing schemes, Unity allows multiple users to write to a drive simultaneously. But in general, it is sensible to limit read/write conflicts by granting write-access only to appropriate workspaces. For example, each user must have access to his or her own render workspace, but only those responsible for dailies need access to the Dailies Picture and Dailies Audio workspaces. It's also best to begin with a small number of workspaces to provide uncluttered desktops for all users. The number and size of workspaces will grow as dailies accumulate.

Backup Considerations

Unity's RAID option provides insurance against drive failure by allowing you to duplicate media files. You can choose to duplicate all your media, or only the material that is in workspaces you are concerned about (those from non-timecoded sources, for example). You can also choose to duplicate individual media files during digitization. Of course, duplicated media uses up twice as much storage, which increases cost.

The alternative to duplication is a backup utility like Retrospect. Though you'd ideally back up everything, your timecoded sources can always be restored from tape and thus are relatively safe. Non-timecoded material is unprotected and should be backed up regularly. Keeping it separate makes that much easier.

Multiple Media Folders

Assistants usually create partitions for render files (precomputes). These eventually fill up, and it's advisable to go through them and weed out unused material, since the Mac OS limits the number of files that can be stored in a single folder. But Unity can be tricked into recognizing more than one media file folder, so you can have as many render files as needed.

Within the OMFI Media Files folder, there are folders named for each person who has write-access to that workspace. If your user name is John, then you'll have a folder called John. As the folder approaches a limit of about 1,200 files, it can be "capped off" by adding a number to the end of the file name (John1, John2, etc.). When you next do something that creates media (digitizing or rendering), a new media folder named John will be created. Unity will read from all these folders but it will only write to the one named John.

The problem with this procedure (which is not officially supported by Avid) is that when you manage media (by using "Delete Unused Precomputes," for example), all folders will be changed, but the only media database that will be updated is the one in your write folder. So, one by one, you must change each folder back to its original name, do your media management, let the database update and then change the name back.

Compatibility

Unity is compatible with both ABVB (Version 7.2 and above) and Meridien (Version 10) media. But media files are not cross-compatible between versions, so those who want to share media must use the same system. As mentioned earlier, Pro Tools users may also share media with Unity. In such cases, it is advisable to use AIFF or .WAV format audio files. Sound editors using Pro Tools 5.0 with the AV/XL video option can also play Avid video, which simplifies sharing of sequences between picture and sound departments.

Shared Projects

With Avid's old media sharing technologies, an editor and assistant working together had to pass bins back and forth across a shared media drive. This was straightforward, but not very flexible. Unity ends that hassle -- you can use it to share projects, which reside on a shared workspace. You can share any or all of your bins, and many cutting rooms will want to share only a portion of them. Only one person can make changes to a bin at a given time, which can create some surprises. Unity helps by letting you easily create and manage access privileges, but you should think carefully about which bins need to be shared in order to avoid confusion. In some cases it will be simpler to copy bins back and forth, or to use a combination of both methods.


Patrick Gallagher is an assistant editor currently working on Spider-Man.
He can be reached at via email