What is the primary role of a codec in audio/video systems?

The primary role of a codec in audio/video systems is to compress and decompress digital audio and video. Codecs are essential for managing the size of multimedia files, allowing for efficient storage and transmission. When audio or video data is captured, it is often in a raw format that can be very large. A codec compresses this data to reduce the file size, which makes it easier and faster to send over networks, store on devices, and play back on various platforms.

When the compressed data needs to be used, the codec then decompresses it, allowing users to access the original quality of audio or video. This dual functionality is crucial in modern audio/video applications, where bandwidth and storage are often limited.

The other options do not accurately represent the fundamental function of a codec. Enhancing image quality, increasing transmission distance, and providing power to devices are not primary functions of a codec and do not address the core purpose of handling audio and video data compression and decompression. Therefore, the option highlighting the compression and decompression capabilities accurately captures the essence of what a codec does within audio/video systems.