Why video files are so large
A minute of 4K footage from a modern phone is around 350MB. Gmail stops at 25MB. That gap is why almost nobody can email a video straight from their camera roll, and why every messaging app quietly ruins your footage instead.
Most of that size is unnecessary for how the video will actually be watched. Recording at 4K makes sense for editing; sending 4K to someone who will watch it on a phone screen does not.
What to change first
Resolution gives you the biggest saving for the least visible loss. Dropping 4K to 720p cuts the pixel count by about 89 percent, and on a phone screen the difference is close to invisible.
After that, adjust quality. The scale here is inverted, which trips people up: a lower number means higher quality and a larger file. 23 looks essentially identical to the source, 28 is a sensible default, and 32 and above starts to show blockiness in fast motion.
Realistic expectations
- Phone footage at 4K or 1080p: typically 70 to 90 percent smaller at 720p.
- Screen recordings: compress extremely well, often over 90 percent.
- Already-compressed downloads: modest savings, sometimes none. A file someone else already compressed has little left to give.
Questions
Why is it so much slower than other sites?
Because those sites upload your video to their servers and compress it there. That is faster, but it means handing your footage to a company, and it is why they cap file sizes and add watermarks — every video costs them money. Here the work happens on your machine, which is slower but private and unlimited.
Can I use my phone?
For short clips, yes. For anything long, a phone may run out of memory and the browser will close the tab. A laptop is far more reliable.
Is my video uploaded?
No. The video never leaves your device. Only the compression engine is downloaded, once, from a public code repository.