VideoCompress Guides

"Convert it to MP4" sounds like one job. It's really two different jobs that happen to produce a file with the same extension: Rewrap : move the same video and audio packets into an MP4 container. It takes seconds, the size stays the same and the picture can't get worse, because nothing is decoded. Re-encode : decode the video and compress it again as H.264. It takes longer and costs some quality, but it's the only route that makes the file smaller or changes what's inside. Which one you need depends on two questions: what codec is inside your .mov or .webm, and does the place you're sending it care about the extension, the codec or the megabytes? I ran both routes on two real files: a 130 MB iPhone-style .MOV and a 113 MB screen recording saved as .WebM. Everything ran in Chrome on videocompress.dev , a browser video tool I build (so read this with that in mind). Nothing was uploaded, and I checked every output with ffprobe . The short answer (measured) ...

You check the file and it says 24 MB. The limit says 25 MB. The upload still fails. Or you run a compressor three times with different quality settings and get 31 MB, then 12 MB, then something that looks like it was filmed through a screen door. Both problems have the same fix: decide the final size first, aim a little under the real ceiling, and let the encoder work backward from that number. Here is how I pick the number, and then a quick run on a real clip with VidSmaller (full disclosure: it's one of the tools I make). The limit you see isn't the limit you get The number a platform publishes is rarely the number your file has to beat. Email. Attachments travel base64-encoded, which makes them roughly 37% bigger on the wire. Gmail measures the encoded message, so a 25 MB video turns into a ~34 MB message. About 18 MB of actual file is what clears it. There's a longer explainer on why Gmail's 25 MB really means about 18 . Outlook.com stops at 20 MB, and Exchange wo...