A Systematic Design of Object-based Bit-rate Control Mechanism in MPEG-4
| Autor: | Guo-liang Luo, 羅國良 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Object-based control is the most different parts from the other digital video standards. A frame is no long just a rectangular picture but a composite picture by arbitrarily shaped video objects. Because of this, the rate control algorithm is not the same as the frame-based video coding undoubtedly. Including 1) The demands of video quality; every object has different importance in multiple video objects. We have to distribute available bit rates to every object according to their importance. 2) The bitsream syntax; in order to have the definition of objects, shape information is added. We use a two-pass mechanism to handle this situation. At the first pass, we collect some information for our video sequences and calculating the variance of each VOP (Video Object Plane). At the second pass, we use the information obtained by the first pass to calculate the quantization parameter. Because CBR(Constant Bit-rate) will reduce the large latency time, we adopt a CBR(Constant Bit Rate) bitstream rather than VBR(Variable Bit Rate). In our simulation, the proposed multiple video objects rate control mechanism not only provides a reasonable bit rate but also controls the quality of video sequences. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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