tailieunhanh - H.264 and MPEG-4 Video Compression phần 5

Nâng cao thời gian thực đơn giản và nâng cao hồ sơ đơn giản). Đây là các cấu hình phổ biến nhất được sử dụng tại thời điểm hiện tại và do đó, họ được bảo hiểm trong một số chi tiết. Công cụ và cấu hình cho mã hóa của các đối tượng hình tùy ý được thảo luận tiếp theo (Core, chính và hồ sơ liên quan), | 100 MPEG-4 VISUAL Advanced Simple and Advanced Real-Time Simple profiles . These are by far the most popular profiles in use at the present time and so they are covered in some detail. Tools and profiles for coding of arbitrary-shaped objects are discussed next the Core Main and related profiles followed by profiles for scalable coding still texture coding and high-quality studio coding of video. In addition to tools for coding of natural real-world video material MPEG-4 Visual defines a set of profiles for coding of synthetic computer-generated visual objects such as 2D and 3D meshes and animated face and body models. The focus of this book is very much on coding of natural video and so these profiles are introduced only briefly. Coding tools in the MPEG-4 Visual standard that are not included in any Profile such as Overlapped Block Motion Compensation OBMC are perhaps contentiously not covered in this chapter. OVERVIEW OF MPEG-4 VISUAL NATURAL VIDEO CODING Features MPEG-4 Visual attempts to satisfy the requirements of a wide range of visual communication applications through a toolkit-based approach to coding of visual information. Some of the key features that distinguish MPEG-4 Visual from previous visual coding standards include Efficient compression of progressive and interlaced natural video sequences compression of sequences of rectangular video frames . The core compression tools are based on the ITU-T standard and can out-perform MPEG-1 and MPEG-2 video compression. Optional additional tools further improve compression efficiency. Coding of video objects irregular-shaped regions of a video scene . This is a new concept for standard-based video coding and enables for example independent coding of foreground and background objects in a video scene. Support for effective transmission over practical networks. Error resilience tools help a decoder to recover from transmission errors and maintain a successful video connection in an error-prone .