Viz Mosart is Vizrt's powerful suite of tools for studio automation, production assistance, and advanced graphics control. It enhances consistency and efficiency in live and as-live production, so that even complex shows can be run error-free from a single operator position.

Viz Mosart controls devices flexibly according to templated sets of repeatable actions, automating that control according to stories prepared in a rundown and enabling creative manual interaction whenever needed.

In this document you will find listed all important changes since Viz Mosart 5.17.

Viz Mosart 5.18.0

Release Date: 2026-10-12

Viz Mosart 5.18 adds an audio mixer driver for LAWO PowerCore over Ember+.

The GV AMPP clip player integration has had a substantial reliability pass. Clip players are reached quickly when players belonging to other salvos are not running, control is recovered by itself after a brief interruption to the platform connection, cues no longer fail on a stray character in a clip identifier, and a clip’s duration is corrected once its media has finished landing.

Template database handling has been improved, so that saving A/V Setup over a WAN is much faster, two people saving at the same time can no longer produce a partially saved template set, and a failed template database read is reported instead of starting silently against an empty repository.

Genlock reporting and switching are more accurate on virtualized systems: a clock disciplined by the hypervisor is recognized as a precision time source, and a video switcher transition is no longer dropped in genlock mode when a template uses Transition Only with a short mix delay.

Important Note

In this release, the remaining Visual Basic source in Viz Mosart has been converted to C#. This is an internal change, and Viz Mosart is intended to behave exactly as it did in 5.17. The conversion was automated and applied in a single pass, with compiler-enforced type checking switched on across the affected code beforehand and unit tests added around the converted server code. It reaches nearly every part of the product, however — the Viz Mosart Server, AV Automation, Overlay Graphics Interface and the Viz Mosart GUI among them — and no test suite exercises every path a live production takes. Vizrt therefore recommends rehearsing with your own configuration, templates and rundowns before taking Viz Mosart 5.18 to air, and reporting anything that differs from 5.17 or earlier to Vizrt Support (MOSART-15139).

Adaptive Live Producer

• New: Selecting a graphics profile can now switch the alternative graphics concept on an Adaptive Live Producer video wall, in this early preview feature. A new Graphics profile concepts table in the ALP settings maps a graphics profile to a concept, either for a named mixer effect or for all of them, and a row naming a mixer effect takes precedence over an "all" row for the same profile. Each mixer effect also gains a Default graphics concept, applied when the wall connects. Profile names are matched exactly, including capitalization, and a profile with no entry leaves the walls unchanged (MOSART-15182).

Switching

• Fixed: With genlock enabled, a template using Transition Only with a mix delay of 6 frames or less lost its video switcher transition altogether — the template appeared in preview and secondary actions such as graphics still fired, but nothing happened on the switcher at take, because the command was never sent. It affected DVE, camera and external source templates alike, with any genlock clock source, and did not occur with genlock switched off. The transition is now performed, and still lands on the correct frame (MOSART-15417).

• Fixed: For Grass Valley switchers driven by the CPL driver, turning a keyer or DSK on or off acted as a toggle rather than setting the state asked for: a template requesting a keyer on would switch it off if it was already on, and the operator’s DSK button could do the opposite of what the panel showed. The requested state is now applied absolutely, so repeating a request leaves the keyer where it is. This has never worked correctly since the CPL driver was introduced (MOSART-15203).

Camera Robotics

• Improved: For Shotoku robotic cameras, a preset recall can now name pages 1 to 40. Previously a recall naming a page above 20 was rejected and the camera did not move (MOSART-15091).

Video Clip Playout

Clip Players

• Fixed: A VIDEO_PORT control command using PREVIEW or ONAIR could act on the wrong clip player port, so nothing happened and the log reported a failure on a port holding no clip. This occurred when a clip was put back into preview while still paused on the port it had played from — a common adlib pattern — and whenever an on-air clip was not on the port the group rotation had advanced to. The command now resolves the port from the item itself (MOSART-15249).

GV AMPP

• Fixed: Viz Mosart fell back to the cloud hub even when a local push notification relay was reachable on the network. Only relay addresses on Viz Mosart’s own subnet were tried, so a correctly configured LocalSubnetMask excluded a relay on a different but routable subnet, and clearing the subnet mask was the only workaround. Viz Mosart now tries every advertised relay address it can reach, preferring addresses on its own subnet, and warns once per change rather than repeatedly while it stays on the cloud hub. An advertised IPv6 address no longer discards the remaining local addresses, and addresses Viz Mosart cannot dial are skipped instead of spending a connection timeout (MOSART-14597).

• Fixed: Cueing a clip took far longer than usual whenever one of the clip player nodes was stopped — typically rising from under 700 ms to around 2 seconds, with peaks near 3 seconds — and the delay applied even to ports excluded from the active salvo. Viz Mosart retries a stopped node indefinitely, and each retry blocked on a ping that held a lock the cue also needed. A node already known to be stopped is now reported as unavailable immediately instead of being pinged again, and a node that answers a later ping is returned to service and reopened (MOSART-14780).

• New: Clips can now be loaded from a file path, without FrameLight X. A new Directory setting on the video server — set in ClipServerAMPP.xml or in the server’s connection string — gives a base folder that relative clip names are resolved against, for example a NAS share. A clip name that is already a full or UNC path is used as it stands, and a relative name must carry a file extension to be treated as a file: a name without one, ending in C or A, is still read as a FrameLight X clip or asset id. Installations that leave Directory empty and do not use full paths are unaffected, and FrameLight X remains optional (MOSART-14821).

• Fixed: A cue could fail on air with The clip identifier '…' is not valid even though the identifier was correct. Stray whitespace — a space, tab or line break picked up while the identifier was cached on the rundown item — made Viz Mosart reject it before anything was sent to the platform. The identifier is now trimmed before it is checked, and when one is genuinely rejected the log names the player and says which identifier forms are accepted (MOSART-15221).

• Fixed: Viz Mosart could lose control of every clip player after a brief interruption to the platform connection, and not recover until the video server subsystem was restarted. The connection returned within a fraction of a second and reported healthy, but the topic subscriptions it carried were not restored, so commands were sent and no response could ever arrive; players then reported as unavailable and were retried in a loop. Subscriptions are now re-sent when the connection returns (MOSART-15342).

• Fixed: A clip’s playhead jumped backwards by a few frames when looping was switched on while the clip was playing. Viz Mosart applies looping to a clip that is already rolling, and it sent its internal whole-clip markers to the platform as though they were real frame positions, repositioning the clip to the start of media. A whole-clip loop now sends only the loop instruction; a genuine in and out range is unaffected (MOSART-15371).

• Fixed: With several salvos configured, Viz Mosart took 20–25 seconds to reach its clip players when the players belonging to other salvos were not running. Each salvo’s ports were opened in turn, and every first open waited out a ping that a stopped player answers only by timing out. Viz Mosart now pings all configured players together when the video server connects, so stopped players cost one timeout between them (MOSART-15486).

Clip Status

• Fixed: For installations using GV AMPP clip players with FrameLight X, a clip could show a duration of a fraction of a second in the rundown while playing in full. The platform can report a provisional length while the media is still being written, and nothing afterwards brought in the settled value: the notification sent when the media lands carries no duration, and since Viz Mosart 5.16 a clip already known to Media Administrator was skipped when the catalogue was re-read, so even a forced refresh returned the old value. Viz Mosart now re-reads the clip when its media lands, and a catalogue re-read settles the duration while leaving the clip’s name, description and state alone (MOSART-15395).

• Fixed: With Enable dynamic configuration switched on, Media Administrator could drop its connection to every clip server a few minutes after starting, and repeatedly after that, each server then backing off before it reconnected. The active video server list is re-sent whenever the remote dispatcher reconnects, and every push rebuilt all clip servers from scratch — disconnecting and re-indexing servers that nothing had asked to change, even when the list was identical to the one already in use. Media Administrator now compares the incoming list against the one it is running and reconnects only the servers whose configuration actually changed. Switching dynamic configuration off is no longer needed as a workaround (MOSART-14585).

Graphics

• Improved: For the AE Live graphics driver, the Clear command in Overlay Graphics Interface now also clears fullscreen graphics, instead of leaving them on air. Mosart now asks the renderer to clear itself rather than taking out each tracked graphic in turn, so on installations using one renderer for both overlay and fullscreen graphics, Clear removes everything on air. Where fullscreen and overlay graphics are on separate renderers, only the targeted renderer is cleared (MOSART-15057).

• Fixed: For Viz Engines driven through a Media Sequencer, an engine that had been reported as disconnected was never reported as connected again, even after the Media Sequencer came back. The per-engine status stayed stale until Viz Mosart was restarted, so a recovered engine still read as down. Engine status now follows the Media Sequencer connection in both directions, and the disconnected message is cleared when the connection returns (MOSART-15382).

• Fixed: In a mirrored engine setup, a macro on a fullscreen graphic was sent only to the first engine. Fullscreen graphics address their engine by number, and that path resolved a single engine instead of every engine sharing the alias — unlike Take and Continue, which already fanned out. Macros now reach every mirrored engine, and the same gap for an Overlay Graphics macro addressed by engine number is closed with it (MOSART-14484).

• Fixed: After a connection to a Media Sequencer dropped and came back, graphics commands were sent on the dead connection and never reached the engines. The playlists stayed bound to the old connection, which could also linger alongside the new one. Viz Mosart now releases everything tied to the dropped connection and rebinds the MOS playlist and the Trio show playlist on the new one, keeping the graphics already stored in the Media Sequencer. Commands queued while disconnected are no longer recorded as having been sent (MOSART-15084).

Audio

Audio Mixers

• New: An audio mixer driver for LAWO PowerCore, over Ember+. In AV Automation, under Devices > Properties on the Audio > Audio mixer tab, select LAWO POWER CORE EMBER+; the driver is then configured in AudioMixerEmberPlus.xml alongside the other Ember+ mixers, where the PowerCore-specific entries are commented with their defaults. Gradual fades are coalesced into one Ember+ message per step, so faders moved together travel in step rather than as independent streams. Prefade listen is not supported by this driver (MOSART-14145).

Audio Players

Rundown and Story Handling

• New: Rundown stories can be filtered in the Viz Mosart GUI by a value from a newsroom column — for example to work through all shots tagged for one studio position. A multi-select dropdown in the rundown area lists the values present in the loaded rundown; selecting one or more hides every other story, and Mosart skips the hidden ones when cueing the next story. The filter is global, so all connected clients and the backup server show the same view, and it can only be changed while the timeline is stopped. Nothing is removed from the rundown: hidden stories keep receiving newsroom updates, and clearing the filter restores all stories. Enable it with the new Use story filter Manus setting (off by default), and map the newsroom column to the story_filter story variable under Story External Metadata in the Newsroom Settings editor (MOSART-14958).

• Fixed: Placeholder entries in the MOS rundown cache could make a real rundown look like a duplicate and cause it to be dropped on the next reload. Mosart records a placeholder holding only the rundown ID when a newsroom system refers to a rundown it does not yet know, and these were never removed from MosRundownCache.xml. They are now cleared when the cache is loaded, and a rundown ID still present more than once is written back only once, with the log naming what was left out (MOSART-15000).

• Fixed: With Default ready to air enabled, a rundown Viz Mosart had not seen before followed the setting when announced with roCreate, but was placed as not ready when announced with roReplace or roList. In READYTOAIR mode a not-ready rundown is not shown in the Viz Mosart GUI at all. A previously unseen rundown now follows the setting however it is announced; one Viz Mosart already knows keeps the ready state it has (MOSART-15228).

Story Recorder

• Fixed: For installations using Story Publisher with Mimir, every publish job leaked a background thread, so a busy broadcast day could exhaust the memory available to AV Automation. When that happened, every operation failed and the Viz Mosart Server dropped both AV Automation and Overlay Graphics Interface, taking the connections to their devices with them, and Viz Mosart had to be restarted. This has been so since Viz Mosart 5.14. Publishing now runs on shared worker threads and leaks nothing (MOSART-15390).

Viz Mosart GUI

• Fixed: NDI live preview in the Viz Mosart GUI could freeze on Connecting and never show video. Newer NDI runtimes report a source-change notification that Viz Mosart did not recognize, which stopped it processing any further frames from that source. The notification is now recognized and ignored, and preview runs normally (MOSART-15354).

• Fixed: Disable rundown autoscroll now behaves as it did before Viz Mosart 5.16. The behavior introduced in Viz Mosart 5.16, keeping the keyboard shortcuts bound to the story selected in the rundown, can be activated with the new Binding always follow selected story setting, off by default. The setting does not change the media pool, which continues to follow Disable rundown autoscroll (MOSART-15384).

Frame Accuracy

• Fixed: On a virtual machine whose clock is disciplined by the host — VMware Precision Clock or Hyper-V — AV Automation showed a permanently yellow genlock indicator and the genlock report said the clock was not PTP-disciplined, although this is a configuration Vizrt recommends. Both hypervisor time providers are now accepted as a precision time source when they report stratum 1. Because such a provider can present itself as a primary reference whether or not the host is itself synchronized, the report states that the clock is synchronized to the hypervisor host, that the host’s own synchronization is not verified, and that the host’s time configuration should be checked. The indicator is display-only; playout timing is unchanged (MOSART-15358).

Remote Control Service and API

Server Administration

Configuration and Settings

• Fixed: The External Panel application's settings window opened empty and could not be used. This has been so since that window was introduced in Viz Mosart 5.15. External Panel settings can be opened and edited again (MOSART-15086).

• Improved: For installations using Template Database, saving A/V Setup over a WAN is much faster. The save rewrote and re-read every router entry regardless of what had changed, which on a large configuration could freeze AV Automation for several minutes or fail with a timeout; it now completes in seconds. The saved configuration is unchanged (MOSART-15214).

• Fixed: For installations using Template Database over a WAN, saving A/V Setup could fail with a database connection error, often naming a template unrelated to the edit. Saves now complete reliably (MOSART-15215).

• Fixed: For installations using Template Database, two people saving at the same time could both proceed, producing duplicate-key errors and partially saved template sets. Only one save now goes through; the other is refused. A refused save also says whether another user is editing or whether Viz Mosart could not secure the database, instead of always reporting it as locked by an unknown user (MOSART-15217).

• Fixed: For installations with a gRPC transport enabled, a channel templates repository larger than 4 MB could not be transferred: template changes saved in the Template Editor never reached Manus Administrator, and devices in AV Automation and Overlay Graphics Interface could be left stuck in Idle. The limit is now 64 MB, on every gRPC channel (MOSART-15337).

• Improved: For installations using a video wall, the wall is now configured in Mosart settings under AV Automation → Video Wall, instead of the Video Wall tab in Device Properties. The settings were previously held per Windows user and could only be read by AV Automation; they now sit centrally with the rest of the Viz Mosart settings. AV Automation carries the existing values over once, on the first start after upgrading, and the old tab points to the new location. Only the fields a wall type uses are shown: Server address for the network types, COM port and Bit rate for Encore, and Backup server address for Pandora (MOSART-15205).

• Fixed: Standby at startup was ignored for Jupiter PixelNet and Watchout video walls, which came up out of standby however the setting was set. It now applies to every video wall type (MOSART-15205).

• Improved: Template changes made in Template Editor 2 are now picked up by AV Automation without restarting it. A new Update server button next to Save tells AV Automation to re-read the template store — the template database or channeltemplates.xml — and pass the result on to Manus Administrator. The message confirms the request was sent, not that the templates are live: a reload is held while a show is running and takes effect at the next Initialize devices or when the server goes idle, and it is declined outright while the old Template Editor is open in AV Automation, so nobody’s unsaved work is overwritten. The AV Automation log records which happened (MOSART-15400).

• Fixed: A failed read of the Template Database at start-up was reported as success, so AV Automation and the Template Editor could come up against an empty or half-populated template set with nothing in the log to explain it. A failed read is now raised: AV Automation logs it, reverts to the last saved files, retries the connection and asks the operator whether to continue, and the Template Editor falls back to the local channeltemplates.xml instead of reporting that templates were read from the database (MOSART-15451).

• New: The External Panel has a new Fill manual lowerthirds only setting. It is on by default, matching what External Panel already did — only manual lowerthirds are bound to panel buttons. Turning it off also binds the automatic, timed lowerthirds from the story. Existing installations are unaffected (MOSART-15444).

Logging

• Improved: The Viz Mosart GUI now logs when it connects to the Viz Mosart Server, on both the new SignalR transport and the default Remoting transport. The GUI prefers SignalR where the server supports it, and on that transport a successful connection was previously not logged at all, leaving no evidence in a log that the GUI had reached the server (MOSART-15373).

Security

• Improved: Third-party dependencies carrying high-severity security advisories have been updated or removed: Newtonsoft.Json upgraded from 11.0.2 to 13.0.4 across the Viz Mosart applications and drivers, and AutoMapper removed from the Viz One integration in Media Administrator. Viz Mosart behaves as before (MOSART-11886, MOSART-15305).

Note: Enabling OIDC authentication on a Mosart Server switches off the shared REST API key entirely. The key is not checked at all, so every integration that authenticates with X-API-Key is refused with 401 — including the Elgato Stream Deck plugin and your own scripts. This has been the behavior since OIDC authentication was introduced in Viz Mosart 5.15. Plan for it before enabling authentication in production.

Known Limitations

• With the new Binding always follow selected story setting switched on, the keyboard shortcuts do not always follow the story an operator has selected. After loading or reloading a rundown they stay on the previous rundown’s story until a story is clicked; a story that Viz Mosart selects automatically on a rundown load is treated as an operator selection; and the behavior is undefined when the setting is used while Disable rundown autoscroll is off. The setting is off by default, and installations that leave it off are unaffected (MOSART-15575).

Deprecations

Recent notable changes

• 5.14.0: the Keyable Timing Display is deprecated, and is no longer included in the Viz Mosart Timing Display installer.

• 5.14.0: the installer for ActiveX NRCS plugin is no longer included, since the ActiveX NRCS plugin was deprecated in Viz Mosart 5.13. Customers will need to use the HTML-based plugin (Mosart Web Apps NRCS Plugin).

• 5.12.0: the legacy Showmaker Windows application is no longer supported. The new Showmaker (currently in early access mode) is part of the Mosart Web Applications (Mosart Web Apps Showmaker).

• 5.11.0: the MMTrio executable is no longer included.

• 5.10.0: It is expected that users of Viz Mosart have now migrated to the Combined Manus Administrator introduced in Viz Mosart 5.2.0. From this version of Viz Mosart, the two original iNews and MOS versions of Manus Administrator are deprecated.

Upcoming changes

• In a future version of Viz Mosart (version TBC), support for the Viz Mosart Timing Display client application will be deprecated. Customers are encouraged to migrate to the HTML-based timing display that is available through the Mosart Web Applications. Vizrt is continuing to strengthen the web-based architecture which serves this timing display, and to enhance its functionality where customer experience exposes use cases which are not yet fully satisfied.

• In a future version of Viz Mosart (version TBC), the Keyboard Shortcut Editor (legacy) in the Viz Mosart GUI will be deprecated, to be fully replaced by the new improved Keyboard Shortcut Editor. This new editor is already available in parallel to the original one in the Viz Mosart GUI. Customers are encouraged to start using this new editor, since Vizrt will continue to enhance its functionality, based on customer experience and feedback.

Installation and Upgrade

Installing for Current user only or for Anyone who uses this computer

Normally, Viz Mosart applications are installed for Anyone who uses this computer, but in some situations it is preferable to install for Current user only. If you have a previous installation for Anyone who uses this computer and then install for Current user only, Windows' Apps & Features will show two installations of the application, both the previous one and the new one, and you will also see two shortcuts on your desktop. This is a feature of Windows, but could lead to confusion with subsequent updates.

• A recommendation to avoid this particular situation is to uninstall the previous Viz Mosart application before installing the new one.

[*] The various Viz Mosart applications shall normally always be on the same version, to ensure compatibility of features. If the Viz Mosart applications were installed under the various users' dedicated locations, then during an upgrade, you would have to repeat the installation of a new version for all Viz Mosart users for that computer. In addition to the time and effort this would require, you risk that some users might miss the upgrade. When one of these users later starts a Viz Mosart application, for example the Viz Mosart GUI, it would no longer be compatible with the commonly upgraded Viz Mosart applications, like the Viz Mosart Server.

Please refer to the Viz Mosart Administrator Guide, section Installation.

System Requirements

Recommendations

For further details, see the Installation > Prerequisites section in the Viz Mosart Administrator Guide.

General

• Microsoft .NET Framework 4.8.

• Microsoft Visual C++ 2015-2022 Redistributable (both x86 and x64).

• Microsoft Edge WebView2 Runtime (x64).

Viz Mosart Server

• Microsoft Windows Server 2025.

• Microsoft Windows Server 2022.

• Microsoft Windows Server 2019 (only with Extended Support from Microsoft - until 2029-01-09).

• Microsoft Windows Server 2016 (only with Extended Support from Microsoft - until 2027-01-12).

• Microsoft Windows Server 2012 R2 (only with Extended Security updates from Microsoft - until 2026-10-13).

Viz Mosart client computers (GUI, Audio Panel, Timing Display, Audio Player)

• Microsoft Windows 11.

• Microsoft Windows 10 (only with the Windows 10 Extended Security Updates program).

Network Bandwidth

• 1000 Mbps (Gigabit) Ethernet card is required on the Viz Mosart client computer if NDI is used for live preview in the Preview and Program windows.

Upgrade

As a standard procedure, always make backups before upgrading. Please backup all files in the following locations:

• C:\channeltemplates

• %localappdata%\Mosart_Medialab

• %programdata%\Mosart Medialab\ConfigurationFiles

• %programfiles(x86)%\Mosart Medialab\<Mosart application>\ConfigurationFiles

• All files with extension .exe.config in folders %programfiles(x86)%\Mosart Medialab\<Mosart application>\ where <Mosart application> is the relevant Viz Mosart application (for example Mosart Server, Mosart GUI).

Windows registry settings for:

• HKEY_CURRENT_USER\Software\[Wow6432Node\]Mosart Medialab

• HKEY_LOCAL_MACHINE\Software\[Wow6432Node\]Mosart Medialab

For the upgrade procedure, see the Viz Mosart Administrator Guide, section Installation.
You will always find the latest updated documentation for Viz Mosart at the Vizrt Documentation Center.

If you do not have Internet access to the above documentation, a quick guide for installation is given here:

1. Download all relevant Viz Mosart installation files to the preferred location.
   The default location is C:\Mosart\Installers. You are advised to make a sub-directory for the installers for a particular version/build containing all the MSI installer-files and any other supplemental files.

2. Stop all Viz Mosart Windows services.

3. Double-click the installation file, and follow the prompts to complete installation. Note that after completing this step for the Viz Mosart Server and the Viz Mosart GUI, the documentation is available in the installation sub-folder Documentation.

4. Repeat the above step for all relevant installation files.

5. As the last steps you may need to start a set of Windows services to make Viz Mosart run properly (not needed after installing the Viz Mosart Server or the Viz Mosart GUI client, these services are started by the installer). The services are configured to automatically start when the computer is started. The safest is to reboot the computer to verify that this automatic start of the services is working.

Installations with Viz Mosart in several galleries

If you have several galleries running an earlier Viz Mosart version, like Viz Mosart 3.x or Viz Mosart 4.x, you can safely upgrade one of the galleries to Viz Mosart 5.x while the others stay on their current version.

Previous Versions

In accordance with the Vizrt Global Support Handbook section Software Lifecycle, support for older versions of Viz Mosart ends 24 months after a subsequent minor or major version is released.

• With this release of Viz Mosart version 5.18, earlier versions will therefore no longer be supported after 2028-10-12

• At the date of this release, Viz Mosart versions 5.8 and earlier are no longer supported.

Documentation

Latest, continually updated documentation for Viz Mosart 5.18 is available at the Vizrt Documentation Center.

Support

Support is available at the Vizrt Support Portal.