Frequently Asked Questions about CADET


  1. What operating systems can I use to run CADET?
    CADET has been tested on OS X and Windows (7 and 10). You can also run CADET on Linux: from the command line or from an executable script, run the following two commands:
    • $ cd <path-to-cadet-directory>/cadet-resources
    • $ node cadet-server —dir ~
  2. CADET does not work with Internet Explorer on Windows. On Windows, you'll need to use another browser, like Chrome or Firefox.

  3. Why do I need to install Node.js in order to run CADET?
    Node.js provides a local Web server (that is, a Web server that runs on your own computer), which makes it possible for CADET to run without being connected to the Internet.
  4. How can I find and install updates to CADET?
    Please check the CADET user group for update announcements. Before installing an update, always be sure to QUIT all previous instances of CADET in all browsers before installing and running the update: from within CADET, open CADET's File menu and choose Quit. Do not simply quit the browser.

Opening and running CADET

  1. I can't seem to get CADET to work in Internet Explorer on Windows. What should I do?
    CADET does not work with Internet Explorer on Windows. On Windows, you'll need to use another browser, like Chrome or Firefox.
  2. When I try to open CADET on my Mac I get a message that the application cannot be opened because it's from an unidentified developer. What should I do?
    Right-click (or Ctrl+click) on "CADET Mac.command," choose Open from the menu and then choose Open from the dialog. You will only need to do this once. See the instructions for opening an unsigned app for additional information.
  3. Can I run CADET in more than one browser simultaneously?
    Yes. If you do run more than one instance of CADET, though, you should not be playing the same media clip.
  4. Can I run CADET from a terminal window?
    Yes. Open a terminal window and follow these steps.

    • CD into the CADET directory.
    • CD into the cadet-resources directory.
    • Type node cadet-server --dir ~ and then press Enter. CADET will open.
    Note: Issuing the command --dir ~ causes CADET to open with file browsing rooted in the home directory. If you do not issue --dir ~, then CADET will open with file browsing rooted in the root directory.
  5. I changed my root directories in Preferences and now Node crashes when I open/play media?
    It's possible that you are experiencing read/write permissions issues in regards to temporary caption files (.temp.vtt). This error is only with version .045, going forward the temp files are stored in the Application Data folder and deleted upon quitting CADET. You can either set your root folders to their default locations, or run the application as an administrator; but we recommend upgrading to version .046 or higher.

Writing and editing captions

  1. I styled some of my captions using colors and different fonts, but these styling features do not appear when I export the captions and play them in a media player. Why not?
    CADET provides a wide range of styling options. However, not all caption formats support all of these styling options: for example, SRT does not support markup for text colors or different font faces. Other formats, such as WebVTT and TTML, do support styling options, but not all media players are capable of correctly interpreting styling markup. So even if you export a TTML file with markup for red text, the target player will show white text if it doesn't know how to interpret the markup for red text.
  2. My caption styles appear correctly in the caption-editing grid in CADET, but the captions in CADET's media player don’t show the styling. Why is that?
    CADET uses WebVTT to display captions in the player.  While WebVTT supports markup for certain kinds of caption styling, some browsers (such as IE, Edge, and Firefox) simply ignore all styling markup that is included in WebVTT files. This is why you will only see styled captions when you are running CADET in a browser that supports the styling markup found in WebVTT. Be assured, however, that the WebVTT files that you export from CADET (as well as other caption formats that support styling markup, such as TTML, QTtext and SAMI) contain the appropriate styling commands, regardless of the browser in which CADET is running. Whether or not your target player will render those styles depends on the player’s ability to interpret the markup correctly.
  3. Can I position captions somewhere other than at the bottom of my video?
    Yes. CADET provides support for both horizontal and vertical placement options, which can be found in the Style>Alignment menu.
  4. Can I change the default display of the captions in CADET's video player?
    Because CADET uses your browser's native video player, the captions in the player might look different from one browser to the next. If you're using IE 11, Edge, or Safari, however, you can change the default look of the captions:
    • IE 11: go to Tools > Internet Options > Accessibility > Captions.
    • Edge: go to Windows > Settings > Ease of Access > Closed captions.
    • Safari: go to System Preferences... > Accessibility > Captions.
    Note: Changing the default caption style in the browser settings will affect the captions that you see in CADET (and for other videos you play in that browser) but will not change the exported caption file.
  5. In IE, when I type Control-O to open a project, a browser dialog appears with no files in it. What should I do?
    In IE, the Ctrl-O key combination is first trapped by the browser itself, which pops up IE’s "Open URL" dialog. Simply close this dialog (either with the mouse or by hitting the Escape key) and CADET's file-browser dialog will fill up with files. Alternatively, you can open the File menu and select Open.
  6. The video I want to caption is on Youtube (or Vimeo), I don't have a local copy. Can I still create captions with CADET?
    Yes, CADET will play back remote video from either Youtube or Vimeo and allow you to create captions and synchronize them to the remote video. While the captions displayed in the CADET video player emulate caption playback on those platforms, you'll have to perform an additional step of importing the captions into the remote platform in order for others to see your captions. When you've finished your project and you're ready to upload the captions to the remote platform, read instructions for uploading caption files to YouTube, and instructions for uploading caption files to Vimeo.

Controlling the video player

  1. Can I control the video player in CADET using the keyboard?
    Yes. See the list of keyboard shortcuts for more information.
  2. Can I control the player with a foot pedal?
    Yes. As of CADET version 2.0.33, there are individual keyboard shortcuts for play and pause. There are many programmable foot pedals which emulate keyboard devices. That is, when you press one of the pedal buttons, the pedal will issue a specific key combination. To the computer, it appears that keys on a keyboard have been pressed.
    By programming the foot pedal to issue the correct key sequence, you can control CADET's media player. You might program your foot pedal to issue a PLAY sequence (Ctrl-Alt(Option)-Space) when depressed and a PAUSE (Ctrl-Shift-Alt(Option)-Space) plus SCRUB-BACKWARD-SMALL (Ctrl-G) sequence upon release, so that it replays a small bit of the last encountered audio the next time it plays. Alternatively, you might program it to issue the PLAY/PAUSE toggle sequence (Ctrl-Space) when depressed and do nothing when released. This would allow you simply to use your pedal instead of the normal CTRL-Space to toggle the player. The options are only limited by the programmability of the pedal. We tested this approach using a 3-button pedal from X-Keys (, but the technique should work with any programmable foot pedal. Note: This is not an endorsement of the X-Keys pedal. See the Keyboard Shortcut and Menu Reference for supported keyboard shortcuts.
  3. When I press CTRL+Spacebar to play/pause the video player, my Mac starts speaking to me. How do I fix this?
    Your Mac's text-to-speech (TTS) function is set to use CTRL+Spacebar to speak selected text. To change this, open System Preferences > Accessibility > Speech. From this window you can either disable the TTS function or reassign the shortcut to another keyboard combination. Learn more about the Mac's TTS capabilities.
  4. I'm using an audio clip to create captions, but I don't see any captions in the player. Why is this and what can I do?
    If you're on a Mac and use Safari, you'll see captions. But if you're using Chrome or Firefox (whether on a Mac or PC), those browsers don't hide the built-in media controller when playing back audio files like they do for video playback. So the controller is actually obscuring the captions. If you select all the rows and set the Style Alignment to Top, then you'll see the captions. You can then set the alignment back to bottom before you export your project.

Importing files into CADET

  1. What file formats will CADET import?
    CADET will import the following file formats: WebVTT, TTML, SRT, QTtext, SCC, DigiDX, DVD STL (Spruce), DVD Adobe Script and plain-text files with the extension ".txt". CADET will not import Word files.
  2. I'm trying to import a file into CADET. I can select the file in the Import File dialog, but the text doesn't get imported into the editor. Why not?
    Make sure that the file you are trying to import has been created as UTF-8 with no BOM (byte order mark). Using an application such as BBEdit, Notepad, TextWrangler, Word, etc., open the file and save it as UTF-8 with no BOM, then try importing the file again.
  3. I've used an automatic-captioning service and the captions are full of errors! Can I import this caption file into CADET and clean it up?
    Yes. Import the auto-generated caption file into CADET (using one of the supported import formats), correct the errors in text and timing, and re-export in the appropriate format for your target video player.

Exporting files from CADET

  1. What file formats will CADET export?
    CADET will export the following file formats: WebVTT, TTML, SRT, QTtext, SAMI, SCC, Description Script (.ad.html), DigiDX, DVD STL (Spruce), DVD Adobe Script and plain-text (.txt) files.
  2. I've exported WebVTT captions and put them in a directory with the video on my computer. When I play the video in my web browser, I don't see any captions. Why?
    Most browsers won’t play captions locally, but if you transfer the WebVTT file and the video to a web server, and create an HTML page which implements a media player using the <video> and <track> elements and references the video and caption file on the web server, you should see the captions. You can also import the captions using many local media players, such as VLC, to watch them locally without uploading your work to a web server.
  3. I've captioned my own remote video clip on YouTube or Vimeo, but when I play the clip in YouTube or Vimeo directly (not in CADET), my captions don't appear. Why?
    CADET does not integrate your captions with the remote video platforms. That's a step that you must undertake yourself. Read instructions for uploading caption files to YouTube, and instructions for uploading caption files to Vimeo.


If your problem is not addressed here you can visit the CADET user group for additional help. Posts are frequently checked by developers and we will do our best to help you!