Questions, answered
Which format should I choose if I’m not sure?
Choose MP4. It plays essentially everywhere, imports into every editor, and is what most upload forms expect. Pick WebM only when you are publishing to the web yourself and want the smaller file, or when a site specifically asks for it.
Does converting reduce quality?
Converting between these formats re-encodes the picture, so yes, some quality is lost. Choosing a higher quality setting keeps the loss invisible in practice. Converting once from your original is fine; converting the same clip back and forth repeatedly is what visibly degrades it.
Can I convert MOV files from my iPhone?
Yes. MOV is accepted as a source and converts to MP4 or WebM. Note that newer iPhones record HEVC (H.265) inside the MOV, which many sites reject — converting to MP4/H.264 here is exactly the fix for that.
Will my audio survive the conversion?
Yes — audio is re-encoded to AAC for MP4 or Opus for WebM and stays in sync. If the source has no audio track, the output will not have one either; the codec plan shown before encoding tells you which case you are in.
Are my files uploaded to a server?
No. The conversion runs in your browser using its own media APIs, so the video never leaves your device. That also means speed depends on your hardware rather than on a queue or your connection.
