Video decoder direct current (DC)/ alternative current (AC) coefficient forecast method and video decoder

Abstract

The invention provides a video decoder direct current (DC) / alternative current (AC) coefficient forecast method. The method has the following steps that a buffer area is preset, blocks needing to forecast and current blocks to be forecasted are stored in the buffer area, a point photoelectric tape reader (PTR) points to the current blocks to be forecasted, and the pointer PTR has an initial value; position serial numbers of the blocks within the buffer area are set; initial values are given to the AC coefficient or the DC coefficient within the buffer area; the current block coefficient is forecasted, and forecasted value is stored in the buffer area; the block coefficient is forecasted according to the position serial numbers of the blocks; the pointer PTR jumps to the initial value of the pointer when points to the end block. A circular buffer area is used for saving the macro block data used in forecasting, so that the forecast coefficient index and boundary judgment are greatly simplified, under the condition of the moderate storage space, the forecast process is simplified, and the forecast efficiency of taking a block as a unit is improved. The invention further provides a video decoder by the method.

Description

technical field [0001] The present invention relates to a video decoder, in particular to a DC / AC coefficient prediction method of the video decoder and a video decoder using the method. Background technique [0002] Currently, multimedia compression technology has been widely used in various consumer products and communication devices, such as VCD players, DVD players, mobile phones, and MP4 players. [0003] A conventional multimedia compression technique is eg the latest MPEG compression technique, MPEG-4. MPEG-4 is capable of providing professional-quality audio and video streaming services over a wide range of bandwidths. MPEG-4 is defined by the Moving Picture Experts Group (MPEG), and the specification officially became an international standard in 2000. [0004] Compared with MPEG-1 and MPEG-2, MPEG-4 is more suitable for interactive AV services and remote monitoring. Its design goal is to make it more adaptable and scalable, and can use a narrow bandwidth to pass ...

AI Technical Summary

Problems solved by technology

The traditional buffer needs to save the DC / AC coefficients of all adjacent 8x8 blocks in the row above the row where the current macroblock is located, and at the same time save the DC of the 8x8 block in the previous column of the row where the current macroblock is located. / AC coefficient to predict the DC / AC coefficient value of each block in the current macroblock, so the memory space that needs to be opened up is: taking the QCIF with a resolution size of 176×144 as an example, each time a macroblock is processed, the DC that needs to be saved The coefficients are (11x2+2+(11+1)x2)=48, and the AC coefficients to be saved are (48x7)=336, a total of 384 coefficients; however, the retrieval process of the coefficients used in the traditional buffer calculation is cumbersome, and every Calculating the coefficients of an 8x8 block needs to start from the calculation of the first address of the previous macroblock row. At the same time, the boundary processing of the first macroblock row and the first macroblock column of each frame is cumbersome, and it needs to be divided into intra-frame or out-of-frame situation, the process has many branches

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