You already set a megabyte cap and the clip is still too big—or too slow to finish in a browser tab. That is when codec choice matters. Use H.264 when recipients must play it everywhere; switch to H.265 only when both ends support it and you need another size cut.
This walkthrough uses VidSmaller, a cloud compressor that hits an exact output size (Advanced mode unlocks H.265 on paid plans).
1. Upload once, keep the laptop cool
Open vidsmaller.com. Drop MP4, MOV, MKV, WebM, or another supported format. Guest accounts have per-file limits and limited credits. There is no watermark; uploads are deleted after processing.
Long 4K timelines belong here—not in a browser tab that can OOM mid-encode.
2. Hit the size first, then choose the codec
In Basic, set Output file size or tap Email / WhatsApp / Discord / Reddit so the two-pass job aims at a real number.
Then open Advanced:
- H.264 + MP4 — default. Widest phone, chat app, and browser playback.
- H.265 — smaller file at the same quality, slower encode, and older devices may refuse it.
- Drop resolution (4K → 1080p or 720p) before you flip codecs if the source is huge.
For hard caps (forms, WhatsApp comfort), target about 1MB under the published limit so overhead does not push you over.
3. Download and verify playback
Start compression, wait for the cloud job, download. You can close the tab; the result link stays until it expires.
Spot-check on the device that will receive the file. If H.265 fails to play, re-run the same size target with H.264 (or one resolution step lower).
Related: why long 4K encodes belong in the cloud, not in a browser tab.
