I-Frame

An I-frame, or intra-coded frame, stores a complete picture on its own, independent of neighboring frames. It is the keyframe that anchors a GOP and the only frame type a decoder can display without reconstructing from others. In long-GOP codecs, I-frames recur periodically and the P- and B-frames in between store only differences. Intra-frame codecs like ProRes and DNxHD make every frame an I-frame, which is why they scrub and trim so smoothly and survive repeated edits well, at the cost of larger files. Editors benefit from understanding I-frames when seeking feels jumpy (you can only cleanly land on or near keyframes in some formats), when setting export keyframe intervals, and when choosing edit-friendly intra-frame intermediates over efficient but harder-to-edit long-GOP source.