An even field has pixel information for lines 2, 4, 6.1080. An odd field consists of pixel information for lines 1, 3, 5.1079. For example, an HD 1080 picture has 1080 lines (rows) of pixels. A frame is a complete image, and a field is the set of odd-numbered or even-numbered scan lines composing a partial image. While the terms 'frame' and 'picture' are often used interchangeably, the term picture is a more general notion, as a picture can be either a frame or a field. The order in which the I, P and B frames are arranged is called the Group of pictures. P and B frames are also called Inter frames. P‑frames are also known as delta‑frames.Ī B‑frame (Bidirectional predicted picture) saves even more space by using differences between the current frame and both the preceding and following frames to specify its content. The encoder does not need to store the unchanging background pixels in the P‑frame, thus saving space. For example, in a scene where a car moves across a stationary background, only the car's movements need to be encoded. Three types of pictures (or frames) are used in video compression: I, P, and B frames.Īn I‑frame ( Intra-coded picture) is a complete image, like a JPG or BMP image file.Ī P‑frame (Predicted picture) holds only the changes in the image from the previous frame. Summary A sequence of video frames, consisting of two keyframes (I), one forward-predicted frame (P) and one bi-directionally predicted frame (B). B‑frames can use both previous and forward frames for data reference to get the highest amount of data compression.P‑frames can use data from previous frames to decompress and are more compressible than I‑frames.I‑frames are the least compressible but don't require other video frames to decode.They are different in the following characteristics: The three major picture types used in the different video algorithms are I, P and B. These different algorithms for video frames are called picture types or frame types. In the field of video compression a video frame is compressed using different algorithms with different advantages and disadvantages, centered mainly around amount of data compression. JSTOR ( October 2008) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed.įind sources: 'Video compression picture types' – news Please help improve this article by adding citations to reliable sources.

Streaming video compression artifacts