Video and subtitle tools

Two tools for the part of video work that is neither shooting nor editing: making a file fit somewhere it was not cut for, and fixing timing that has drifted.

The aspect ratio and crop planner shows what survives when a 16:9 edit is cut to 9:16, 1:1 or 4:5, including where each platform's interface covers the frame. That is the difference between a caption that reads and one hidden behind a progress bar. Subtitle sync shifts or rescales SRT and VTT timings, which is what a file needs when it was cut for a different frame rate or when a cold open was added after the subtitles were made.

Most subtitle drift is a frame rate problem, not an offset. Film runs at 24 frames per second and NTSC video at 23.976, a difference of exactly 0.1 percent. A file authored against one and played against the other stays almost in sync at the start and ends up roughly four seconds out after an hour, which reads as an offset for the first ten minutes and then stops making sense. A shift moves every cue by the same amount and cannot fix that. Rescaling multiplies the timings, which can. Knowing which of the two you are looking at is most of the job, so the tool shows the drift across the whole file rather than only at the point you are checking.

Crop safe zones are platform-specific and they move. A 9:16 export loses roughly the top and bottom eighth of the frame to the interface on most feeds, but not the same eighth on each, and captions burned into that band disappear on one platform while surviving on another. The planner draws the overlay rather than describing it, because a caption either clears the progress bar or it does not and that is a question about pixels.

Nothing you open here is uploaded. Subtitle files are read in the browser with the File API and never leave the machine, which matters when the file is an unreleased cut under embargo. There is no account and no server to hold anything.