A video codec is a technology used to compress and decompress digital video files. It allows for efficient storage and transmission of video data by reducing the file size while maintaining quality. Common video codecs include H.264, H.265, and VP9, each with its own strengths and applications. When a video is recorded, it is often too large to store or share easily. A codec processes the video to make it smaller, which is essential for streaming services like YouTube or Netflix. When you play a video, the codec decompresses it, allowing you to view the content smoothly.