tailieunhanh - H.264 and MPEG-4 Video Compression phần 7

(máy tính tạo ra) các đối tượng trực quan như mắt lưới 2D và 3D và đối mặt với hoạt hình cơ thể mô hình. Trọng tâm của cuốn sách này là rất nhiều mã hóa video tự nhiên và các cấu hình này được giới thiệu chỉ một thời gian ngắn. tiêu chuẩn bao gồm một loạt các công cụ và quy trình mã hóa và | 162 MPEG4 PART 10 to give D n identical to the D n shown in the Encoder . Using the header information decoded from the bitstream the decoder creates a prediction block PRED identical to the original prediction PRED formed in the encoder. PRED is added to D n to produce uFn which is filtered to create each decoded block F n. STRUCTURE Profiles and Levels defines a set of three Profiles each supporting a particular set of coding functions and each specifying what is required of an encoder or decoder that complies with the Profile. The Baseline Profile supports intra and inter-coding using I-slices and P-slices and entropy coding with context-adaptive variable-length codes CAVLC . The Main Profile includes support for interlaced video inter-coding using B-slices inter coding using weighted prediction and entropy coding using context-based arithmetic coding CABAC . The Extended Profile does not support interlaced video or CABAC but adds modes to enable efficient switching between coded bitstreams SP- and SI-slices and improved error resilience Data Partitioning . Potential applications of the Baseline Profile include videotelephony videoconferencing and wireless communications potential applications of the Main Profile include television broadcasting and video storage and the Extended Profile may be particularly useful for streaming media applications. However each Profile has sufficient flexibility to support a wide range of applications and so these examples of applications should not be considered definitive. Figure shows the relationship between the three Profiles and the coding tools supported by the standard. It is clear from this figure that the Baseline Profile is a subset of the Extended Profile but not of the Main Profile. The details of each coding tool are described in Sections and starting with the Baseline Profile tools . Performance limits for CODECs are defined by a set of Levels each placing limits on .