PSNR/SSIM Metrics and Subjective Quality: How to Use Them

PSNR compares signal difference using mean squared error; SSIM models structural similarity across luminance, contrast, and structure components.

High scores do not guarantee pleasing results; banding, temporal flicker, and fine‑texture loss may be undervalued by metrics but obvious to viewers.

Compare against a high‑quality reference; evaluate multiple scenes, especially dark gradients and motion; avoid optimizing for a single number without visual checks.

Perform A/B viewing on calibrated displays; include different devices; ask for feedback from non‑experts to capture real‑world perception.

Pick CRF/presets that survive gradient and motion tests; accept slightly lower metric scores if the video looks cleaner and more stable to humans.

Run a CRF sweep and record PSNR/SSIM along with subjective notes; compress with Vibbit and compare segments: /tools/video-compress

Video compression methods: CRF, bitrate, resize