Configurable Video Transition Duration in Reel Quick

Video transitions are one of those details that quietly shape the feel of an edit. In Reel Quick issue #13 , the goal was simple: let users control how long a scene transition lasts instead of forcing a fixed value. Issue URL: https://github.com/ronin1770/reel-quick/issues/13 The problem The app already supported transition effects between scenes, but the duration was fixed. That meant creators could choose what transition to use, but not how long it should run. For short-form video, that matters a lot: fast transitions create a snappier pace longer transitions feel smoother or more cinematic some edits need no transition at all The feature The new behavior adds a configurable transition duration: minimum: 0.0 seconds maximum: 4.0 seconds step: 0.5 seconds A slider in the frontend lets the user choose the duration, and that value is sent to the backend for FFmpeg video generation. If the value is 0.0 , transitions are disabled entirely. The FFmpeg math When two clips are joined with a transition, the transition overlaps the end of the first clip and the start of the second clip. So the final duration is: final length = clip 1 + clip 2 - transition duration Example 1 Clip 1 = 7 seconds Clip 2 = 8 seconds Transition duration = 4 seconds Math: 7 + 8 - 4 = 11 seconds Final video length: 11 seconds Example 2 Clip 1 = 7 seconds Clip 2 = 8 seconds Transition duration = 0.5 seconds Math: 7 + 8 - 0.5 = 14.5 seconds Final video length: 14.5 seconds Why validation matters This feature also needs guardrails. The backend validates that: the duration is between 0 and 4 the duration is a multiple of 0.5 clips are long enough for the selected transition That last point is important. A 4 second transition cannot work safely if a clip itself is only 3 seconds long. Implementation notes The implementation touches both frontend and backend: Frontend add a transition duration slider show the selected value beside it send transition_duration in the video creation request show inline vali