I have a Node app that downloads audio and video, and uses ffmpeg to combine them into a single file.
I had been using ffmpeg-static - npm (npmjs.com) as part of the app on Heroku to spawn the child process, but this generates a segmentation fault error when it is called.
Reading another topic here stated that ffmpeg is part of the standard environment, so I changed to command to just use that, but now the error is “stderr: ‘/bin/sh: 1: ffmpeg: not found\n’”.
It sounds like you’re using Docker and not a Native Environment. Render Native Environments do have ffmpeg available by default.
If you only used Node & the ffmpeg buildpacks on Heroku, you may find it simpler to deploy directly to a Native Environment to avoid some of the complications of Docker.