Knowledge Base

Getting Started with Video Slave 4


Video Slave 4 is easy to use and to setup. This article will tell you all you need to know to use Video Slave's synchronized video playback abilities as quickly as possible. 

The main feature of Video Slave 4 is its ability to playback movies in sync to external timecode sources. MIDI Timecode (MTC) is used for synchronized playback, MIDI Machine Control (MMC) is used for locating while not playing and scrubbing. As a timecode source, you can use any kind of device or software that can supply MTC or MMC. In this tutorial, we will assume you're using one of the standard Digital Audio Workstations that can supply both MTC and MMC.

Note: There's a persistent issue with Pro Tools loop playback and MTC. To enable synchronized playback also when looping, you will need to setup Video Slave as a HUI remote - either using the built-in virtual MIDI ports or by setting up additional network MIDI ports for HUI. Setup is explained here.

Let's get started!

When you launch Video Slave, the main window will be shown. As you can see, it consists of four sections - the tab section which contains a number of setting panes, the video section which the video output will be displayed in, the controller bar which contains the main counter box as well as playback and fullscreen controls and the editing section which displays the contents of the currently active timeline.

VS 4 GettingStarted 1

To start, drag a movie file to the media tab of the tab section at the top left of the main window. Alternatively, use File -> Add Media to Project. This will add the movie to the project's media bin. Think of the media bin as a place where all the files in the project live. To play back the movie file you just added, you will need to drag and drop it to a video track on the timeline in the editing section of the window. Hold the Alt key while dragging to move the video to its original timecode if one is present in the file.

When dropped onto a video track, this will add a video region to the video track and create audio tracks and regions for all audio tracks the movie contains. Video and the corresponding audio regions will always be linked (also when editing them) to make sure they're always in sync with each other.

Timelines and how to use them

With the release of Video Slave 4, we switched from a playlist-based approach used in previous versions to a timeline-based approach. This makes working with media much easier and more versatile than in the previous versions as it allows editing and it's also much more intuitive for starters using the software.

Each project in Video Slave can contain several timelines. Each timeline has a start TC, a duration and a frame rate and contains an event track as well as a number of audio and video tracks. It is perfectly fine to just use one timeline in a project but you also have the ability to use several of them. One example for the use of several timelines would be if you're e.g. working on a feature film consisting of several reels; you can have one timeline with all reel movies starting at the individual hours and another one where they are tied together for review for example. There are other scenarios where using more than one timeline can make sense as well.

You can change the timeline start TC and duration as well as add new or delete existing timelines in the "Timelines" tab of the tab section in the top left corner of the main window.

By default, new timelines have a start TC of 01:00:00:00 (this can be adjusted in the user preferences). We recommend adapting the timeline start TC to a value matching your project's timecode range for best operation. So if you're working on a project around a 10:00:00:00 timecode start, it makes sense to set the timeline start TC to e.g. 09:59:00:00. You can do that by selecting the current timeline (the one with the check box next to it ticked) in the "Timelines" tab and by clicking the "Edit" button.

When the timeline's timecode range is correctly set for your project, the next step is to set the movie's start TC to the correct value in order to play it back in sync to your timecode source. This can be done by double-clicking the video region which will open the "Properties" panel of the tab section.

VS 4 GettingStarted 2

You can now playback the movie, assign audio track outputs, enable the TC/Feet and Frames overlay and edit the video and audio regions. What's not working yet is the synchronized playback. We're going to get to that next.

MIDI Timecode/MIDI Machine Control setup

Video Slave plays back movies in sync using MIDI Timecode (MTC) and additionally uses MIDI Machine Control (MMC) for scrubbing and locating while not playing. It doesn't matter for Video Slave if the MIDI information is coming from a separate machine or from the same machine. It also doesn't matter if the timecode comes from a physical MIDI interface or through the network using macOS' built-in network MIDI. You only need to tell Video Slave where the MIDI data is coming from.

To do so, open the preferences and select the "General" tab (if it isn't already shown).


If you want to use Video Slave on the same machine, we recommend using the virtual ports Video Slave creates automatically. Using them doesn't require any additional setup steps. If you're using a physical MIDI interface receiving MIDI information from another machine, you can also just select that here. If you want to use network MIDI, you need to create a MIDI port first before you can select it in the dropdown menus. There's an extra article for you discussing the few extra steps needed. It is of course ok to connect the same input to both the MTC and the MMC In.

DAW MIDI Timecode/MIDI Machine Control setup

What you need to do to prepare your DAW to actually send MIDI timecode and MIDI Machine Control depends on the DAW you're using. We prepared a separate article to give you more information about it.

Synchronized playback

Once your DAW is setup and the MIDI inputs within Video Slave are configured correctly, you're almost done. You should now see the incoming timecode and the timecode rate in the MIDI I/O section of the General preferences changing when you hit play or scrub within your DAW.

Now you only need to tell Video Slave to follow external sync by clicking the sync button. If you also setup MMC, it should now also follow the locate commands while not playing.

VS4 GettingStarted 3

Common pitfalls

If the incoming timecode changes and the sync button is enabled on (the button should be blinking) but Video Slave doesn't follow, there are a couple of things to look out for.

  • Timecode rate mismatch
    MIDI Timecode and MIDI Machine Control messages both don't only carry the actual timecode address but also the timecode frame rate. It is important that the incoming timecode frame rate matches the frame rate of the movie that should play in sync. To make sure, please check both the timecode frame rate of the timeline in Video Slave and the timecode output setting in your DAW.
  • Timecode range mismatch
    Please make sure that the timecode range of your timeline matches the timecode range of your DAW. As an example: if your DAW sends timecode information starting at 01:00:00:00 and Video Slave's timeline start timecode is set to 10:00:00:00, the movie will only play once your DAW reaches the 10:00:00:00 mark. There are two ways of handling this scenario. The first is to change the timecode range of your DAW or to set the timecode range of the timeline within Video Slave as discussed above.

If synchronized playback still doesn't work, please feel free to get in touch.

Notes on using the fullscreen mode in Video Slave 4

With the release of Video Slave 4 we switched to using Apple's official fullscreen API. This however can cause that all of the attached screens (except for the one Video Slave uses for fullscreen) go black when the fullscreen mode is entered.

To get around this, please open the macOS system preferences -> Mission Control and make sure "Displays have separate spaces" is set.

Mission Control prefs