I frame and P Frame

Ref: http://bbs.csdn.net/topics/280002948

1. NAL, slice and frame meanings and Their Relationships

NAL refers to the network extraction layer, which contains some network-related information.
Slice means slice. In 264, the image is divided into one frame or two fields, and the frame can be divided into one or several slilce ); A piece consists of a macro block (MB. Macro Block is the basic unit for encoding.

2. 1 (encoding band of non-IDR image), 2 (encoding Band Data Segment A), and 3 (encoding band data segment B) in nal nal_unit_type), 4 (encoding Band Data Segment c), 5 (IDR image encoding band) Types
Three encoding modes: I _slice, p_slice, and B _slice
The five types in nal nal_unit_type indicate what information is next and how to block specific data.
I _slice, p_slice, and B _slice indicate I-type slice, p-type slice, and B-type slice. here, I _slice is the intra-frame prediction mode encoding; p_slice is the unidirectional prediction encoding or intra-frame mode; B _slice is the bidirectional prediction or intra-frame mode.

3. Are there three types of frames: I frame, P frame, and B frame?
The differences between I frame, P frame, and B frame are as follows: I _slice, p_slice, B _slice, slice, and frame, which are already known in question 1.

4. At last, what frames are 6 (SEI), 7 (SPS), and 8 (PPS) in nal nal_unit_type?
NAL nal_unit_type is a sequence parameter set (SPS), image parameter set (PPS), and enhancement information (SEI. It indicates that the subsequent data information includes the sequence parameter set (SPS), image parameter set (PPS), and enhancement information (SEI ).