This app is essential. The caption files I’m provided with when uploaded to facilitate captioning being visible or hidden line up to the start of the film. With the branding bumper inserted the film doesn’t start until the bumper has played. Sublititle files .srt are time coded text files. To insert a time period each consequent time code has to be amended.
In a nutshell that is what this app does. Full stop!
App Store for Mobile and MAC desktop
Restricted time length on the free version