Hi. Unfortunatelly is not possible. I hope in a future version a better list input management to be implemented.
Until then you can see start-stop time only with the use of a 3rd party program and schedule your videos like https://forums.vmix.com/...t-drag-n-drop-for-videos

Hi. At first keep in mind that Vmix as advertised is not a professional playout server/software so we need to workaround by using the avaliable tools they give us. So in my opinion the term "timeline" is not correct. Other than this. The best way to do what you need (and what i personally do and im open to any ideas for better improvement) is to use vmix input. I insert my video that i need to cut in specific point in Vmix,then i use the vmix mark in-mark out points and rename for example video1. Then in Vmanager i select Events-->add event-->input and i write the input (for example Video1) and set the duration. Then in vmanager i continue for the next video/input as usual
Also you can for a video in Vmanager you can use the button "fixed duration" and give in-point for this video so it play from that point or give a duration and video will play until this duration. But in this vmanager versions source code there exist a bug that when we select a in-point in a video and the remain duration is smaller from the in-point video, then it will not load and play. For example if a video is 30 minutes and we set as in-point 15 minutes and 01 seconds so the remain duration is 14.59 then this video will not load. So better to use vmix input. In the new version im building, this bug is fixed
Be aware also that the mark in-mark out points in video inside vmix and how much accurate they will be the cuts,it depends on the video format. See for example here for more about this https://forums.vmix.com/...ith-Mark-In-and-Mark-Out