How to use Video Compressor
The Video Compressor reduces the file size of MP4, WebM, MOV and MKV videos by re-encoding them at a lower bitrate using H.264 or H.265 — all processed locally in your browser without uploading your footage anywhere. Compress large recordings, drone footage or screen captures before emailing, uploading to a CMS or posting to social media while retaining acceptable visual quality.
- Click "Select Video" and open the video file you want to compress.
- Choose the target quality level using the CRF slider (lower CRF = higher quality and larger file; try CRF 28 as a starting point).
- Select the output codec — H.264 for maximum compatibility, H.265 for better compression.
- Optionally set a maximum output resolution to further reduce file size.
- Click Compress and monitor the progress bar; download the compressed video when done.
Your data never leaves your device — 100% private processing.
Understanding CRF and target bitrate
Constant Rate Factor (CRF) is the primary quality control for H.264 and H.265 encoding. CRF 0 is lossless; CRF 51 is the worst quality. For H.264 a CRF of 18–28 is considered visually acceptable for most content, with 23 being the default. H.265 (HEVC) achieves similar visual quality at roughly half the bitrate of H.264 at the same CRF, making it the better choice when compatibility with older devices is not required. Target bitrate mode is an alternative that constrains file size but may vary quality across scenes.
| CRF | Perceived quality | Relative file size |
|---|---|---|
| 18 | Visually lossless | Very large |
| 23 | High (default) | Medium-large |
| 28 | Acceptable | Medium |
| 35 | Noticeable artefacts | Small |
H.264 vs H.265 for compression
H.264 (AVC) is the most universally supported video codec — playable on virtually every device, browser and platform without any additional software. H.265 (HEVC) delivers significantly better compression, achieving the same perceived quality at roughly half the bitrate, but requires hardware or software decoder support that older devices and some browsers may lack. For files destined for modern platforms (YouTube, Vimeo, recent mobile devices), H.265 is excellent. For maximum reach including older smart TVs and legacy browsers, H.264 is safer.
Worked examples
Phone clip at CRF 23
Inputs: 1080p, 1 min, default CRF 23
Result: Typically 15–40 MB — varies by motion
Smaller share file
Inputs: 1080p → 720p at CRF 28
Result: Often well under half the original size
Common video resolutions and typical H.264 bitrate
| Resolution | Dimensions | Typical bitrate |
|---|---|---|
| 480p | 854 × 480 | 1–2 Mbps |
| 720p | 1280 × 720 | 2.5–4 Mbps |
| 1080p | 1920 × 1080 | 4–8 Mbps |
| 4K (2160p) | 3840 × 2160 | 35–45 Mbps |
Glossary
- CRF (Constant Rate Factor)
- A quality-based encoding mode for H.264/H.265 where a single number from 0 (lossless) to 51 (worst) controls overall quality and file size.
- Bitrate
- The number of bits used per second of video; higher bitrate means better quality and larger file size.
- H.264 (AVC)
- Advanced Video Coding; the most widely supported lossy video codec, balancing quality, compression and compatibility.
- H.265 (HEVC)
- High Efficiency Video Coding; achieves roughly 50% better compression than H.264 at equivalent quality but requires modern decoder support.
- Lossy compression
- A compression method that permanently discards some data to achieve smaller file sizes; video quality decreases with each re-encode.
Related reading
Frequently Asked Questions
Why use Video Compressor?
- H.264 CRF encoding can cut file size by up to 80% with minimal visible quality loss
- H.265 option achieves equivalent visual quality at roughly half the H.264 output size
- Set a target output resolution to reduce oversized 4K source footage further
- CRF slider gives granular control over the quality-to-file-size trade-off
Common use cases
- Shrink a 2 GB drone video to under 200 MB to attach it in a project management tool
- Compress a screen recording to fall within a CMS platform's file upload size limit
- Re-encode a 4K source to 1080p H.265 before uploading to a client delivery portal
- Compress a batch of event videos to send via a free file-transfer service
- Prepare a compressed preview cut of a film to share for feedback before final delivery
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