The biggest mistake when compressing video is starting with “what CRF should I use?” The better first question is: where is this video going? A chat preview, a client review, a long-term archive, and a hard file-size limit do not have the same answer.
Start with the destination
The same 1080p recording can be handled very differently:
- Group chats and social previews: 720p is usually enough. On a small screen, the quality loss is hard to notice.
- Client or team review: keep 1080p if the video contains UI, tables, subtitles, or anything the viewer has to read.
- Archival: avoid dropping resolution just to save space; adjust quality first.
- A hard size limit: Discord, email, or an upload form may force you to use a bitrate cap.
In one line: don’t compress before you know what “good enough” means.
Cut before you compress
The cheapest compression is not an encoder setting — it’s a shorter video.
If your recording has 30 seconds of dead air, 12 seconds of fumbling for a window, and 20 seconds of “okay, that’s the end,” cutting those parts first can remove a meaningful chunk of the file before any re-encoding happens.
So the order is:
- Trim the start, end, and filler with the Video Trimmer.
- Compress the remaining clip in the Video Compressor.
- Only then decide whether you need to normalize it to MP4 with the Format Converter.
Do not compress first and trim later. That wastes time and makes the result harder to control.
Don’t drop resolution by reflex
Resolution is a big size lever, but it’s also the fastest way to make a video look bad. Use it deliberately:
| Source | Destination | Reasonable output |
|---|---|---|
| 1080p phone video | Chat / social preview | 720p |
| 1080p screen recording | Team review | 1080p or 720p |
| 1440p / 4K camera clip | Social upload | 1080p |
| 4K screen recording | Email / chat | 720p or 1080p |
Don’t keep 4K just because the source is 4K. If the useful content is a talking head, a desktop app, or code, 1080p is often plenty — and 720p may survive compression better than 4K squeezed into a tiny file.
No hard limit? Use CRF
If your goal is “smaller, but still looks good,” CRF is usually the right tool. It is a quality target, not a size promise:
| CRF | Meaning | Use it for |
|---|---|---|
| 18–20 | Visually close to the source | Archives, future editing |
| 23 | Balanced default | General sharing |
| 26–28 | Smaller, still acceptable | Chat apps, social previews |
| 30+ | Aggressive | Only when you know it’s acceptable |
If you are unsure, start at CRF 27. If the result looks good and the size is acceptable, stop. If it looks soft, step down to 25 or 24.
Hard limit? Use a bitrate cap
Some destinations don’t care how good your file looks if it’s 21 MB and the limit is 20 MB. Discord’s free upload cap and many email attachment limits are the classic cases. This is where a bitrate cap is more useful than CRF alone.
Estimate a starting bitrate:
target bitrate ≈ target file size × 8 ÷ duration in seconds
For a 4-minute video that must fit under 20 MB:
20 MB × 8 = 160 Mbit
160 ÷ 240 seconds ≈ 667 kbit/s
That’s a starting point, not a guarantee. Static screen recordings and talking-head clips need fewer bits than fast camera movement.
Scenario cheat sheet
| Scenario | Practical approach |
|---|---|
| Chat / social preview | Trim first, then 720p and CRF 26–28 |
| Discord / email | Estimate a bitrate cap, then verify the result |
| Internal demo / tutorial | Keep 1080p when text matters, around CRF 23 |
| Archive / future editing | Keep resolution, CRF 18–20 |
| “Must be small enough to send” | MP4 first, then compress carefully |
Common mistakes
- Looking only at the file size. If faces turn mushy or text becomes unreadable, the compression is too aggressive.
- Compressing before trimming. You’re spending bits on footage nobody needs.
- Forcing 4K into a tiny file. A 720p or 1080p version often looks better.
- Ignoring audio. Meetings, interviews, and tutorials spend real space on the audio track.
- Assuming changing the container compresses the video. MP4/MKV/MOV are containers; the codec and bitrate still decide size.
Try it
Trim the junk first with the Video Trimmer, then run a test at CRF 27 in the Video Compressor. If the file is small enough, stop. If not, reduce resolution or move to a bitrate cap.
Everything runs locally in your browser; the file does not upload.
FAQ
Q: Is lower CRF always better? A: No. Lower CRF preserves more quality, but produces a bigger file. Use lower values for archiving or further editing; 26–28 is often better for simple sharing.
Q: The file is still too big. What next? A: Make sure you trimmed it. Then reduce resolution. Use a bitrate cap only after those.
Q: Can I always fit a video under 20 MB? A: Not always. It depends on duration and motion. A short static screen recording is easy; a long high-motion clip needs more trimming or lower resolution.
Q: Should I convert to MP4 first? A: Usually you can do it in one step. Convert first only if the source format is unusual or your target platform rejects it.