If you were looking for a specific app or service named , please clarify, as current results primarily highlight general live-to-MP4 workflows and tools like Guide Live for interactive tours. MP4 & WebM Recording | Ant Media Documentation
If you want to "go live" using a file you’ve already created (pre-recorded streaming): Bflivemp4
Services like Livepush allow you to upload an MP4 video and broadcast it as a "live" event to multiple platforms simultaneously. If you were looking for a specific app