I’m working on VideoCutTool as a part of GSoC 2019, our project is almost done, we hosted our tool-back-end in toolforge, here https://tools.wmflabs.org/video-cut-tool-back-end/
This server has ffmpeg installed, we implemented video encodings using ffmpeg, This tool is working fine locally, I along with my GSoC mentor tested this several times in several ways in a server, always we are facing the same error 
Error: ffmpeg not found.
We also tried use ffmpeg to test a video rotation in the server using CLI in toolforge server this works fine, but if we run the tool this is failing (ffmpeg not found)
 front-end: https://github.com/gopavasanth/video-cut-tool-front-end/
 back-end: https://github.com/gopavasanth/video-cut-tool-back-end/
Any ideas/suggestions please ?