Industrial Technology Research Institute

Sunplus Technology Co., Ltd.

Ming-Ting Sun

Chia-Wen Lin

Jeongnam Youn

Zhi Zhou

Shin-Huang Chang

Wen-Hao Wang

Yuh-Feng Hsu

Yeping Su

Hung-Hseng Hsu

A method for fast multiple reference frame motion estimation, which is used to perform motion estimation between a current frame and reference frames Fn&#x2212;1, Fn&#x2212;2, . . . , Fn&#x2212;k. The method performs a special block matching to find a plurality of motion vectors for blocks of each frame with respective to a previous frame and then composes motion vector(s) of the current frame referring to the reference frame Fn&#x2212;(k&#x2212;1) and a motion vector of the reference frame Fn&#x2212;(k&#x2212;1) referring to the reference frame Fn&#x2212;k into composed motion vectors of the current frame referring to the reference frame Fn&#x2212;k for the block in the current frame. The method selects a composed motion vector with a minimum of cost function from the composed motion vectors produced when composing the motion vectors and then finely adjusts the composed motion vector selected, thereby obtaining an adjusted motion vector.

Method for fast multiple reference frame motion estimation

Methods and systems for fast variable block-size motion estimation based on merging and splitting procedures for AVC video encoding are disclosed. The methods take advantage of the correlation of the Motion Vectors (MVs) of the different block-size modes to achieve a good computation reduction. Considering that the smaller the block-size difference between two block-sizes is, the more correlations between their MVs can be expected, the methods use a 8*8 block as an initial processing block to calculate prediction MVs. The prediction MVs are then used in predicting MVs for other block-sizes.

System and method for fast variable-size motion estimation

A method for fast macroblock mode decision is disclosed. The method includes: (A) determining if a motion cost at the origin (0, 0) or a prediction motion vector (PMV) for a 4n*4n macroblock is smaller than a first threshold; (B) if the motion cost is smaller than the first threshold, determining a macroblock mode as 4n*4n and ending the method; (C) if the motion cost is not smaller than the first threshold, using an adaptive diversity search strategy to perform motion estimation on four 2n*2n blocks associated with the 4n*4n macroblock; (D) determining if all motion costs of the four 2n*2n blocks in step (C) are smaller than a second threshold; and (E) if step (D) determines that the motion costs of the four 2n*2n blocks are smaller than the second threshold, determining the macroblock mode as 2n*2n and ending the method.

Method for fast macroblock mode decision based on motion cost of variable block size

Methods and systems for providing a video stream from a server to a client over a network include a memory for storing a forward-encoded bit-stream and a reverse-encoded bit-stream for a video data. The forward-encoded bit-stream includes I-frames encoded without inter-frame dependencies and P-frames encoded depending on forward-direction preceding frames, and the reverse-encoded bit-stream includes I-frames and P-frames encoded depending on reverse-direction preceding frames. When the server receives a request with a video cassette recording (VCR) function from the client, the server reads out and transmits frames selectively from among the first, second, third, and fourth frames in accordance with the request. The server can select the closest I-frame to a requested frame in either bit-stream for a fast-mode play or a random-access play, and switch the bit-streams to use subsequent P-frames in a different direction than that of the closest I-frame.

Methods and systems for video streaming with VCR functionality

A transcoder for transcoding digital video signals includes a decoder and an encoder. In the decoder, an end-of-block (EOB) position of an incoming block received by the decoder is determined and a discrete cosine transform (DCT) block type is determined based on the determined EOB position. A reduced number of DCT coefficients is computed in a subsequent inverse DCT computation based on the DCT block type. In the encoder, if the incoming block is intercoded, no DCT coefficients are computed after the EOB of the incoming blocks is performing a DCT. Further, in the encoder when the incoming block is intercoded, an algorithm is applied to predict which DCT coefficients may become zero after a subsequent quantization operation, and only DCT coefficients that may not become zero are computed in performing the DCT.

Transcoding apparatus and method

Methods and systems for generating motion vectors for re-encoding video signals are disclosed. The motion vector is determined by the sum of a base motion vector and a delta motion vector. In the case of no frame-skipping, the base motion vector is the incoming motion vector. In the case of frame skipping, the base motion vector is the sum of the motion vectors of the incoming signal since the last re-encoded frame and the current frame. The delta motion vector is optimized by a minimum Sum of the Absolute Difference by searching over a smaller area than if searching for a new motion vector without a delta motion vector. These methods and systems may be used to improve re-encoding digital video signals.

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Mercer Island, WA, United States of America

Ming-Ting Sun