how can I view milliseconds with VLC? (and why is this method not working?)

According to mederi, the author of the Time extension, the var.add_callback( ) and var.del_callback( ) Lua functions are no longer available in VLC 2.1.

Unless VLC is patched to add the removed functions the script will not work as written.

With VLC, I have found two approaches for determining milliseconds.

Approach 1. Addon: Jump to time (Previous Frame).

• Install Jump to time Previous Frame via the macOS menu VLC > Addons Manager or the Ubuntu menu Tools > Plugins and extensions > Addons Manager tab > Extensions. In VLC 3, click the "Find more addons online" button. The online install page is here.

• Restart VLC.

• Use the menu is under VLC -> Extensions -> Jump to time (Previous frame) to open the dialog below depicted. [Note: older VLC placed the extension under the View menu.] The Jump to time (Previous frame) Get time >> button updates to show HH:MM:SS,mmm. (Note: this is a different dialog then Jump to time in the Playback menu).

Approach 2. Calculate/Estimate . One can estimate milliseconds based the MM:SS that is displayed as follows:

• Stop slightly more than one second prior to the point of interest.
• Use the Next frame e hot key to count frames after when the seconds display changes values to the point of interest.
• Use the Frame rate from the Media Information Window > Codec Details tab to convert to an approximate milliseconds value.
• frame_count / frame_rate = 0.mmm seconds
  The margin of error will be: 0.5/frame_rate = 0.mmm seconds

Maybe an alternative solution for some people. Instead of VLC, import the video into avidemux. It shows milliseconds:

and you are able to jump from Keyframe to Keyframe: