Data compression reduces file size by encoding data more efficiently. It exploits redundancies in data like neighboring pixel values (spatial redundancy) or similar frames (temporal redundancy) in images and video. Compression can be lossless, preserving all information, or lossy, sacrificing some quality for higher compression ratios important for storage, transmission speed and bandwidth. Common lossless methods include run-length and Huffman coding while lossy techniques like JPEG, MP3 and MPEG are usually used for images, audio and video.