What this converter actually supports
Convertr uses the deployed FFmpeg toolchain for published audio and video routes. A container such as MP4, MOV, MKV, AVI, or WebM can hold different codecs, so the file extension alone does not guarantee that a particular player will accept the contents.
Use the dedicated HEVC-to-MP4 or H.265-to-H.264 tools when you need a playable container or wider codec support.
The public upload limit is 1 GB. Convertr does not reduce dimensions, duration, resolution, or output quality merely to manage worker load.