High-definition (HD) channels are television channels that broadcast content with a higher resolution than standard definition (SD) channels. This means that the picture quality is clearer and more detailed, providing a better viewing experience. HD channels typically have a resolution of 720p, 1080i, or 1080p, which allows for sharper images and more vibrant colors. To access HD channels, viewers usually need a compatible television and a subscription to a cable or satellite service that offers these channels. Many popular networks, such as HBO, ESPN, and BBC, provide HD versions of their programming, making it easier for audiences to enjoy movies, sports, and shows in enhanced quality.