If a video cuts off early, tools like Untrunc can sometimes repair the file header by comparing it with a working video from the same source.
Wondershare UniConverter or Canva Video 2.0 provide advanced features like proxy creation, AI enhancement, and timeline editing.
If an MP4 won't play on a phone despite working on a PC, it may be using an unsupported codec profile or missing a "moov atom"—a piece of metadata that needs to be at the start of the file for streaming.
Tools like Adobe Express allow you to upload a file and convert it in seconds.
I recorded a meeting but forgot to press "stop recording". now i got a mp4 file with 0 bytes and a .webex file with with ~300 MB ( Cisco Community
If you have a video in a different format and need an MP4, you can use several free and paid tools: