Quantization adjustments for DC shift artifacts
    42.
    发明申请
    Quantization adjustments for DC shift artifacts 有权
    DC偏移伪影的量化调整

    公开(公告)号:US20070248163A1

    公开(公告)日:2007-10-25

    申请号:US11400785

    申请日:2006-04-07

    IPC分类号: H04N11/04

    摘要: A video encoder identifies one or more portions of a video picture that contain DC shift blocks and adjusts quantization (e.g., by selecting a smaller quantization step size) to reduce contouring artifacts when the picture is reconstructed. The encoder can identify the portion(s) of the picture that contain DC shift blocks by identifying one or more gradient slope regions in the picture and analyzing quantization effects on DC coefficients in the gradient slope region(s). The encoder can select a coarser quantization step size for a high-texture picture portion.

    摘要翻译: 视频编码器识别包含DC移位块的视频图像的一个或多个部分,并且调整量化(例如,通过选择较小的量化步长)以减少重构图像时的轮廓伪影。 编码器可以通过识别图像中的一个或多个梯度斜率区域并分析对梯度斜率区域中的DC系数的量化效应来识别包含DC移位块的图像的部分。 编码器可以为高纹理图像部分选择较粗的量化步长。

    Hybrid motion vector prediction for interlaced forward-predicted fields
    43.
    发明授权
    Hybrid motion vector prediction for interlaced forward-predicted fields 有权
    用于交错前向预测场的混合运动矢量预测

    公开(公告)号:US07616692B2

    公开(公告)日:2009-11-10

    申请号:US10933956

    申请日:2004-09-02

    摘要: Techniques and tools for hybrid motion vector prediction for interlaced forward-predicted fields are described. For example, a video decoder determines an initial motion vector predictor for a motion vector of an interlaced forward-predicted field. The decoder then checks a variation condition based at least in part on a predictor polarity selection (e.g., same or opposite), the initial motion vector predictor, and neighbor motion vectors. If the variation condition is satisfied, the decoder uses one of the neighbor motion vectors as a final motion vector predictor. Otherwise, the decoder uses the initial motion vector predictor as the final motion vector predictor. A video encoder performs corresponding processing.

    摘要翻译: 描述了用于隔行正向预测场的混合运动矢量预测的技术和工具。 例如,视频解码器确定用于隔行扫描前向预测场的运动矢量的初始运动矢量预测器。 解码器至少部分地基于预测器极性选择(例如相同或相反),初始运动矢量预测器和相邻运动矢量来检查变化条件。 如果满足变化条件,则解码器使用相邻运动矢量之一作为最终运动矢量预测器。 否则,解码器使用初始运动矢量预测器作为最终运动矢量预测器。 视频编码器执行相应的处理。

    Quantization adjustments for DC shift artifacts
    45.
    发明授权
    Quantization adjustments for DC shift artifacts 有权
    DC偏移伪影的量化调整

    公开(公告)号:US08503536B2

    公开(公告)日:2013-08-06

    申请号:US11400785

    申请日:2006-04-07

    IPC分类号: H04N7/12

    摘要: A video encoder identifies one or more portions of a video picture that contain DC shift blocks and adjusts quantization (e.g., by selecting a smaller quantization step size) to reduce contouring artifacts when the picture is reconstructed. The encoder can identify the portion(s) of the picture that contain DC shift blocks by identifying one or more gradient slope regions in the picture and analyzing quantization effects on DC coefficients in the gradient slope region(s). The encoder can select a coarser quantization step size for a high-texture picture portion.

    摘要翻译: 视频编码器识别包含DC移位块的视频图像的一个或多个部分,并且调整量化(例如,通过选择较小的量化步长)以减少重构图像时的轮廓伪影。 编码器可以通过识别图像中的一个或多个梯度斜率区域并分析对梯度斜率区域中的DC系数的量化效应来识别包含DC移位块的图像的部分。 编码器可以为高纹理图像部分选择较粗的量化步长。

    Adjusting quantization to preserve non-zero AC coefficients
    46.
    发明授权
    Adjusting quantization to preserve non-zero AC coefficients 有权
    调整量化以保持非零AC系数

    公开(公告)号:US08130828B2

    公开(公告)日:2012-03-06

    申请号:US11400741

    申请日:2006-04-07

    IPC分类号: H04B1/66 H04N7/12 H04N11/02

    CPC分类号: H04N19/126 H04N19/61

    摘要: A video encoder identifies one or more AC coefficients of each of plural blocks in the picture. The encoder identifies a threshold quantization step size such that the identified AC coefficient(s) of each of the plural blocks are nonzero after quantization according to the threshold quantization step size. The threshold quantization step size is such that quantization according to the next higher quantization step size would result in at least one of the identified AC coefficient(s) of at least one of the plural blocks being zero. For example, identifying the threshold quantization step size comprises identifying n top AC coefficients in each of four blocks of a macroblock, determining the smallest AC coefficient among the identified n top AC coefficients of the four blocks, and iteratively evaluating the smallest AC coefficient with respect to candidate quantization step sizes until the threshold quantization step size is identified.

    摘要翻译: 视频编码器识别图像中的多个块中的每一个的一个或多个AC系数。 编码器识别阈值量化步长,使得根据阈值量化步长,多个块中的每一个的所识别的AC系数在量化之后是非零的。 阈值量化步长使得根据下一较高量化步长的量化将导致至少一个多个块中的至少一个的系数中的至少一个为零。 例如,识别阈值量化步长包括识别宏块的四个块中的每一个中的n个顶部AC系数,确定四个块的所识别的n个顶部AC系数中的最小AC系数,并且相对于 到候选量化步长,直到识别阈值量化步长。

    Adjusting quantization to preserve non-zero AC coefficients
    48.
    发明申请
    Adjusting quantization to preserve non-zero AC coefficients 有权
    调整量化以保持非零AC系数

    公开(公告)号:US20070237221A1

    公开(公告)日:2007-10-11

    申请号:US11400741

    申请日:2006-04-07

    IPC分类号: H04N11/04

    CPC分类号: H04N19/126 H04N19/61

    摘要: A video encoder identifies one or more AC coefficients of each of plural blocks in the picture. The encoder identifies a threshold quantization step size such that the identified AC coefficient(s) of each of the plural blocks are nonzero after quantization according to the threshold quantization step size. The threshold quantization step size is such that quantization according to the next higher quantization step size would result in at least one of the identified AC coefficient(s) of at least one of the plural blocks being zero. For example, identifying the threshold quantization step size comprises identifying n top AC coefficients in each of four blocks of a macroblock, determining the smallest AC coefficient among the identified n top AC coefficients of the four blocks, and iteratively evaluating the smallest AC coefficient with respect to candidate quantization step sizes until the threshold quantization step size is identified.

    摘要翻译: 视频编码器识别图像中的多个块中的每一个的一个或多个AC系数。 编码器识别阈值量化步长,使得根据阈值量化步长,多个块中的每一个的所识别的AC系数在量化之后是非零的。 阈值量化步长使得根据下一较高量化步长的量化将导致至少一个多个块中的至少一个的系数中的至少一个为零。 例如,识别阈值量化步长包括识别宏块的四个块中的每一个中的n个顶部AC系数,确定四个块的所识别的n个顶部AC系数中的最小AC系数,并且相对于 到候选量化步长,直到识别阈值量化步长。

    Adaptive video encoding using a perceptual model
    49.
    发明授权
    Adaptive video encoding using a perceptual model 有权
    使用感知模型的自适应视频编码

    公开(公告)号:US08422546B2

    公开(公告)日:2013-04-16

    申请号:US11137924

    申请日:2005-05-25

    IPC分类号: H04B1/66

    摘要: A video encoder includes a region detector module that classifies blocks of video frames. An adaptive filter module applies a median filter to a block based upon a block classification assigned by the region detector module. An adaptive quantization module quantizes a block according to a quantization method adaptively determined based upon a block classification assigned by the region detection module. In one example, a video encoder adaptively determines a median filter selected using a block classification. In another example, a video encoder adaptively determines whether to drop an isolated last transform coefficient based on the block classification, and/or applies a dead-zone selected using the block classification.

    摘要翻译: 视频编码器包括对视频帧块进行分类的区域检测器模块。 自适应滤波器模块基于由区域检测器模块分配的块分类将中值滤波器应用于块。 自适应量化模块根据由区域检测模块分配的块分类自适应地确定的量化方法量化块。 在一个示例中,视频编码器自适应地确定使用块分类选择的中值滤波器。 在另一示例中,视频编码器基于块分类自适应地确定是否丢弃隔离的最后变换系数,和/或应用使用块分类选择的死区。

    Motion vector coding and decoding in interlaced frame coded pictures
    50.
    发明授权
    Motion vector coding and decoding in interlaced frame coded pictures 有权
    在交错帧编码图像中的运动矢量编码和解码

    公开(公告)号:US07924920B2

    公开(公告)日:2011-04-12

    申请号:US10933882

    申请日:2004-09-02

    摘要: In one aspect, an encoder/decoder receives information for four field motion vectors for a macroblock in an interlaced frame-coded, forward-predicted picture and processes the macroblock using the four field motion vectors. In another aspect, an encoder/decoder determines a number of valid candidate motion vectors and calculates a field motion vector predictor. The encoder/decoder does not perform a median operation on the valid candidates if there are less than three of them. In another aspect, an encoder/decoder determines valid candidates, determines field polarities for the valid candidates, and calculates a motion vector predictor based on the field polarities. In another aspect, an encoder/decoder determines one or more valid candidates, determines a field polarity for each individual valid candidate, allocates each individual valid candidate to one of two sets (e.g., opposite polarity and same polarity sets) depending on its field polarity, and calculates a motion vector predictor based on the two sets.

    摘要翻译: 一方面,编码器/解码器接收用于隔行扫描帧编码的前向预测图像中的宏块的四个场运动矢量的信息,并使用四个场运动矢量处理该宏块。 在另一方面,编码器/解码器确定多个有效的候选运动矢量并计算场运动矢量预测器。 如果编码器/解码器中有少于三个,编码器/解码器不对有效候选进行中位数操作。 在另一方面,编码器/解码器确定有效候选,确定有效候选的场极性,并且基于场极性计算运动矢量预测器。 在另一方面,编码器/解码器确定一个或多个有效候选,确定每个单独有效候选的场极性,根据其场极性将每个单独的有效候选分配给两组中的一个(例如,相反的极性和相同极性集) ,并且基于两组来计算运动矢量预测器。