What is CRF and how does it affect compression?

CRF (Constant Rate Factor) controls the quality-to-size tradeoff in H.264 encoding. Lower CRF values mean higher quality and larger files (0 = lossless). Higher values mean more compression and smaller files. CRF 23 is considered visually lossless for most content. CRF 28 is a good balance. CRF 35+ shows visible quality loss.

What is the tradeoff between quality and file size?

Every compression involves a quality tradeoff. At CRF 23 (High), you get minimal quality loss with moderate size reduction — ideal for archiving. CRF 28 (Medium) is the sweet spot for sharing — noticeable only in side-by-side comparisons. CRF 35 (Low) is best when file size matters most, like email attachments.

What is the best compression for email and WhatsApp?

Email typically limits attachments to 25 MB. WhatsApp limits videos to 16 MB (iOS) or 64 MB (Android). Use Medium or Low quality settings to hit these targets. Also consider reducing resolution — a 720p video at medium quality is usually under 10 MB per minute.

Video Compressor

Reduce video file size while maintaining quality. Choose your target quality level and compress instantly in your browser — no upload, no watermark.

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Comment utiliser — Video Compressor

Upload your video

Drag and drop any video file (MP4, WebM, MOV, AVI) or click to browse. Your file stays on your device — nothing is uploaded.

Choose quality level

High quality preserves visual fidelity (~30% smaller). Medium is the sweet spot (~50% smaller). Low maximizes compression (~70% smaller).

Compress and download

Click "Compress Video" to re-encode with CRF-based compression. See the before/after file size comparison and download.

Questions Fréquentes

How much can you compress a video?

Typically 30-70% depending on quality setting. High (CRF 23) gives ~30% reduction with virtually no visible difference. Medium (CRF 28) gives ~50%. Low (CRF 35) gives ~70% with some visible artifacts.

What is CRF?

CRF (Constant Rate Factor) controls quality vs. size. Lower CRF = higher quality, larger files. CRF 23 is "visually lossless." CRF 28 is the balanced sweet spot. CRF 35+ shows noticeable quality loss.

Quality vs. file size — what should I choose?

High for archiving and professional work. Medium for social media sharing and general use. Low when file size is critical — email attachments, WhatsApp, etc.

Best setting for email and WhatsApp?

Email limits: ~25 MB. WhatsApp: 16 MB (iOS) / 64 MB (Android). Use Medium or Low quality. Also consider reducing resolution — 720p at medium quality is usually under 10 MB/min.