ProRes, Photo-JPEG, H.264 (or H.265) are video codecs available at iStock. Short for compression/decompression, codecs are programs designed to address large video file sizes, making them easier to store and share. ProRes and Photo-JPEG Ideal for projects involving post-production effects, such as TV commercials. These codecs offer the best video quality, but as a tradeoff, file sizes are generally larger. H.264 (Advanced Video Coding) and H.265 (High Efficiency Video Coding) These codecs offer high-definition and allow for easier sharing between users. H.264 is the most common codec for web, social, and digital uses.