摘要:
A video encoder receives a macro-block of an image frame, and determines whether the macro-block contains text. The video encoder computes a quantization parameter for quantizing the macro-block, with the quantization parameter computed to be smaller if the macro-block is determined to contain text. The video encoder encodes the macro-block using the quantization parameter. Text quality in the encoded macro-block is preserved.
摘要:
Several techniques aimed at reducing computational complexity when encoding uses bi-predictively encoded frames (B-frames) are implemented in a video encoder. In an embodiment, B-frames are not used as reference frames for encoding P-frames and other B-frames. Non-use of B-frames allows a de-blocking filter used in the video encoder to be switched off when reconstructing encoded B-frames, and use of a lower complexity filter for fractional-resolution motion search for B-frames. In another embodiment, cost functions used in motion estimation for B-frames are simplified to reduce computational complexity. In one more embodiment, fractional pixel refinement in motion search for B-frames is simplified. In yet another embodiment, predictors used in motion estimation for a macro-block in a P-frame are selected from a B-frame that uses a same reference frame as the P-frame.
摘要:
Several methods and a system to perform determination of a field referencing pattern are disclosed. In one aspect, a method is disclosed. A motion vector of a previously coded frame is analyzed using a processor and a memory. A statistic is updated based on whether the motion vector includes one or more of a fractional pel vertical component, a half pel vertical component, and an integer pel vertical component. A field referencing pattern of a target field is determined based on the statistic and an exception protocol.
摘要:
A method for conserving memory accesses in motion compensation of compressed video gathers a plurality of motion compensation data accesses into a single bounding box for direct memory access data transfer. The method places the motion compensation data of a current macroblock into a current bounding box until placing the motion compensation data into the current bounding box causes the ratio of motion compensation data to bounding box data to fall below a predetermined memory utilization threshold.
摘要:
In one aspect, code-words of variable lengths are decoded using a multi-stage decoding approach, with different stages being of different sizes (and thus accepting input data of corresponding number of bits). According to another aspect, the same bit positions are used for storing symbol information and offset value in case of hit and miss results respectively, thereby reducing the width of the entries of the decoding table. According to yet another aspect, conditional processing is avoided by providing a common arithmetic operation when decoding code-words in various escape modes, but using neutral operand values in case the operation is not required.
摘要:
Several methods and systems for estimating motion in a plurality of multimedia pictures are disclosed. In an embodiment, at least one temporal distance between a multimedia picture and one or more reference pictures corresponding to the multimedia picture in a capture order associated with the plurality of multimedia pictures is computed. The at least one temporal distance is computed subsequent to an encoding of the multimedia picture. At least one motion estimation parameter is determined based on the at least one temporal distance. Motion associated with a subsequent multimedia picture to be encoded is estimated based on the at least one motion estimation parameter.
摘要:
This invention predicts that intra mode prediction is more effective for the macro blocks where motion estimation in inter mode prediction fails. This failure is indicated by a large value of the inter mode SAD. This invention performs intra mode prediction for only macro blocks have larger inter mode SADs. The definition of a large inter mode SAD differs for different content. This invention compares the inter mode SAD of a current macroblock with an adaptive threshold. This adaptive threshold depends on the average and variance of the SADs of the previous predicted frame. An adaptive threshold is calculated for each new predictive frame.
摘要:
Several methods and systems for estimating motion in a plurality of multimedia pictures are disclosed. In an embodiment, at least one temporal distance between a multimedia picture and one or more reference pictures corresponding to the multimedia picture in a capture order associated with the plurality of multimedia pictures is computed. The at least one temporal distance is computed subsequent to an encoding of the multimedia picture. At least one motion estimation parameter is determined based on the at least one temporal distance. Motion associated with a subsequent multimedia picture to be encoded is estimated based on the at least one motion estimation parameter.
摘要:
The method, system, and apparatus of source statistics based intra prediction type is disclosed. In one embodiment, a method includes classifying a four-pixel square block in an edge class (e.g., may include a DC edge class, a vertical edge class, a horizontal edge class, a diagonal edge class, and/or a planar edge class) based on an edge classifier, classifying an eight-pixel square block having the four-pixel square block and other four-pixel square blocks as a homogenous class if the four-pixel square block and the other four-pixel square blocks of the eight-pixel square block belong to the edge class, assigning a direction to the edge class of the eight-pixel square block, and determining an optimal intra-prediction type through the classification such that empirical testing of all possible ones of the edge class and the direction is avoided when the homogenous class is identified.
摘要:
A method of rate control in coding of a video sequence to generate a compressed bit stream is provided that includes computing a sequence base quantization step size for a sequence of pictures in the video sequence, computing a picture base quantization step size for a picture in the sequence of pictures based on the sequence base quantization step size, a type of the picture, and a level of the picture in a rate control hierarchy, and coding the picture using the picture base quantization step size to generate a portion of the compressed bit stream.