What type of frame can be coded without reference?

The I-Frame, or Intra-coded Frame, is the type of frame that can be coded without reference to any other frames. It is a self-contained image that allows for the full restoration of the picture without needing any additional data from other frames. This characteristic makes I-Frames essential in video compression and streaming, as they serve as key entry points in the video stream. Because they do not rely on other frames, I-Frames provide a solid foundation for the decoding process, thereby enabling the playback of video sequences even in the absence of surrounding frames.

In contrast, P-Frames (Predictive Frames) and B-Frames (Bidirectional Frames) require the context provided by other frames for their reconstruction. P-Frames predict their content based on the preceding frames, while B-Frames can utilize both preceding and succeeding frames to achieve greater compression efficiency. Reference Frames refers to any frame utilized by other frames for the decoding process. These frames necessitate a foundation provided by I-Frames or other frames to decode properly, thus underlining why they cannot be encoded independently unlike I-Frames.