Typical Group of Pictures (GOP) Structure
The typical Group Of Pictures (GOP) structure is IBBPBBP... The I-frame is used to predict the first P-frame and these two frames are also used to predict the first and the second B-frame. The second P-frame is predicted using the first P-frame and they join to predict the third and fourth B-frames. The scheme is shown in the next picture:
This structure suggests a problem because the fourth frame (a P-frame) is needed in order to predict the second and the third (B-frames). So we need to transmit the P-frame before the B-frames and it will delay the transmission (it will be necessary to keep the P-frame).
This structure has strong points:
- It minimizes the problem of possible uncovered areas.
- P-frames and B-frames need less data than I-frames, so less data is transmitted.
But it has weak points:
- It increases the complexity of the decoder, which can mean more memory is needed to rearrange the frames.
- The interpolated frames (namely B-frames) require more motion vectors which means an increased bit rate.
Read more about this topic: Inter Frame
Famous quotes containing the words typical, group, pictures and/or structure:
“Compare the history of the novel to that of rock ‘n’ roll. Both started out a minority taste, became a mass taste, and then splintered into several subgenres. Both have been the typical cultural expressions of classes and epochs. Both started out aggressively fighting for their share of attention, novels attacking the drama, the tract, and the poem, rock attacking jazz and pop and rolling over classical music.”
—W. T. Lhamon, U.S. educator, critic. “Material Differences,” Deliberate Speed: The Origins of a Cultural Style in the American 1950s, Smithsonian (1990)
“Unless a group of workers know their work is under surveillance, that they are being rated as fairly as human beings, with the fallibility that goes with human judgment, can rate them, and that at least an attempt is made to measure their worth to an organization in relative terms, they are likely to sink back on length of service as the sole reason for retention and promotion.”
—Mary Barnett Gilson (1877–?)
“When lions paint pictures men will not always be represented as conquerors. When women translate laws, constitutions, bibles and philosophies, man will not always be the declared heard of the church, the state, and the home.”
—Elizabeth Cady Stanton 1815–1902, U.S. women’s rights activist, author, editor. The Revolution (August 13, 1868)
“The verbal poetical texture of Shakespeare is the greatest the world has known, and is immensely superior to the structure of his plays as plays. With Shakespeare it is the metaphor that is the thing, not the play.”
—Vladimir Nabokov (1899–1977)