Video Compression Calculator

The Video Compression Calculator recommends optimal encoding settings for any combination of codec, resolution, frame rate, and quality target. It generates a ready-to-use FFmpeg command so you can immediately encode with the best settings for your use case.

Understanding CRF (Constant Rate Factor)

CRF is the primary quality control parameter in H.264 and H.265 encoding. It ranges from 0 (lossless) to 51 (worst quality). Lower CRF = higher quality = larger file. The default (23 for H.264, 28 for H.265) produces a good balance. Recommended values: 18 = visually lossless, 23 = high quality streaming, 28 = good quality web video, 32+ = low quality preview.

Codec-Specific Settings

H.264 (libx264): Use -crf and -preset. Slower presets provide better compression at the same quality. For streaming use preset medium or fast. For archival use slow or veryslow. H.265 (libx265): Same CRF scale as H.264 but CRF 28 ≈ CRF 23 in H.264 quality. Significantly smaller files. AV1 (libaom-av1): CRF range 0–63. Very slow encoding — use hardware encoder (SVT-AV1) for speed. VP9 (libvpx-vp9): Use -crf and -b:v 0 for quality-based encoding. Apple ProRes: No CRF — uses profile-based quality (Proxy, LT, 422, 422 HQ, 4444). Choose profile based on required quality and file size balance.

Encoding Presets

FFmpeg presets control the trade-off between encoding speed and compression efficiency: ultrafast, superfast, veryfast, faster, fast, medium (default), slow, slower, veryslow. A slower preset gives you smaller files at the same quality, at the cost of encoding time.