Question 1717 – Computer-Graphics

A Group Of Pictures can contain the following picture types:
I picture (or) I frame (intra coded picture) – a picture that is coded independently of all other pictures. Each GOP begins (in decoding order) with this type of picture.
P picture (or) P frame (predictive coded picture) – contains motion-compensated difference information relative to previously decoded pictures. Each P picture can only reference one picture, and that picture must precede the P picture in display order as well as in decoding order and must be an I or P picture.
B picture (or) B frame (bi predictive coded picture) – contains motion-compensated difference information relative to previously decoded pictures. Each B picture can only reference two pictures, the one which precedes the B picture in display order and the one which follows, and all referenced pictures must be I or P pictures.

D picture or D frame (DC direct coded picture) – serves as a fast-access representation of a picture for loss robustness or fast-forward. D pictures are only used in MPEG-1 video.