Picture & Audio Quality
Resolution
The number of pixels that make up a video frame, commonly expressed as width by height (like 1920x1080 for 1080p).
Higher resolution means more visual detail, but only up to what a compressed stream's bitrate can actually support — a poorly compressed 4K stream can look worse than a well-compressed 1080p one. Resolution and compression quality are related but genuinely separate factors in overall picture quality.