What is perceptual quality?

Video encoding always involves some quality loss due to compression processes. The goal is to achieve the best possible compression for a specific use case while considering factors like compatibility with players, deliverability over the internet, time to encode, cost to store, and perceptual quality (PQ). PQ measures how close an encoded video looks compared to the original source video. Lossy compression is often used in video encoding as it allows for significant reduction in file size but results in imperfect reproduction of the original content. Popular algorithms for estimating PQ include PSNR, SSIM, and VMAF. Achieving a high-quality video involves balancing factors like bitrate, cost, and usability to ensure optimal viewing experience for end users.