Pre-dithering in high dynamic range video coding

    公开(公告)号:US10027963B2

    公开(公告)日:2018-07-17

    申请号:US15035551

    申请日:2014-11-10

    摘要: An encoder receives an input enhanced dynamic range (EDR) image and a corresponding lower dynamic range (LDR) image to be coded at a given target rate. Before coding, a pre-dithering process is applied to the input LDR image to generate a dithered LDR image at a second bit depth, lower than its original bit depth. The pre-dithering process includes: generating uniformly-distributed noise, applying a spatial filter to the noise to generate low-pass or high-pass filtered noise, applying a temporal high pass or low pass filter to the spatially-filtered noise to generate output noise, adding the output noise to the input LDR image to generate a noise-enhanced LDR image, and quantizing the noise-enhanced image to generate the dithered LDR image. Selecting the characteristics of the dithering filters is based on both the target bit rate and luminance characteristics of the pixels in the input LDR image.

    Adaptive reshaping for layered coding of enhanced dynamic range signals
    57.
    发明授权
    Adaptive reshaping for layered coding of enhanced dynamic range signals 有权
    自适应重构用于增强动态范围信号的分层编码

    公开(公告)号:US09584811B2

    公开(公告)日:2017-02-28

    申请号:US14898574

    申请日:2014-06-16

    发明人: Guan-Ming Su

    摘要: An encoder receives an input enhanced dynamic range (EDR) image to be coded in a layered representation. Input images may be gamma-coded or perceptually-coded using a bit-depth format not supported by one or more video encoders. The input image is remapped to one or more quantized layers to generate output code words suitable for compression using the available video encoders. Algorithms to determine optimum function parameters for linear and non-linear mapping functions are presented. Given a mapping function, the reverse mapping function may be transmitted to a decoder as a look-up table or it may be approximated using a piecewise polynomial approximation. A polynomial approximation technique for representing reverse-mapping functions and chromaticity translation schemes to reduce color shifts are also presented.

    摘要翻译: 编码器接收要以分层表示编码的输入增强动态范围(EDR)图像。 输入图像可以使用不被一个或多个视频编码器支持的位深度格式进行伽马编码或感知编码。 将输入图像重新映射到一个或多个量化层,以使用可用的视频编码器生成适合于压缩的输出码字。 提出了确定线性和非线性映射函数的最优函数参数的算法。 给定映射函数,反向映射函数可以作为查找表发送到解码器,或者可以使用分段多项式近似来近似。 还提出了用于表示反向映射函数和色度转换方案以减少颜色偏移的多项式近似技术。

    Guided color transient improvement filtering in video coding
    58.
    发明授权
    Guided color transient improvement filtering in video coding 有权
    视频编码中的引导色彩瞬态改善滤波

    公开(公告)号:US09338470B2

    公开(公告)日:2016-05-10

    申请号:US14748004

    申请日:2015-06-23

    发明人: Guan-Ming Su Sheng Qu

    摘要: An encoder receives a target image in a standard dynamic range and a guide image in a high dynamic range, wherein both the target image and the guide image represent the same scene. A color transient improvement (CTI) filter is selected to predict a chroma component of a decoded version of the target image based on both the luma and chroma components of the target image and the guide image. The filtering coefficients for the CTI filter are computed by minimizing an error measurement (e.g., MSE) between pixel values of the decoded image and the guide image. The computed set of filtering coefficients is signaled to a receiver (e.g., as metadata). A decoder receives the coded image and the metadata, and applies the same CTI filter to the decoded image to generate an output image.

    摘要翻译: 编码器接收标准动态范围内的目标图像和高动态范围内的引导图像,其中目标图像和引导图像都表示相同的场景。 选择颜色瞬态改善(CTI)滤波器以基于目标图像和引导图像的亮度和色度分量来预测目标图像的解码版本的色度分量。 通过最小化解码图像的像素值和引导图像之间的误差测量(例如,MSE)来计算CTI滤波器的滤波系数。 所计算的滤波系数组被发送给接收机(例如,作为元数据)。 解码器接收编码图像和元数据,并将相同的CTI滤波器应用于解码图像以产生输出图像。

    Joint base layer and enhancement layer quantizer adaptation in EDR video coding
    59.
    发明授权
    Joint base layer and enhancement layer quantizer adaptation in EDR video coding 有权
    EDR视频编码中的联合基层和增强层量化器适应

    公开(公告)号:US09219916B2

    公开(公告)日:2015-12-22

    申请号:US13908926

    申请日:2013-06-03

    摘要: An encoder receives one or more input pictures of enhanced dynamic range (EDR) to be encoded in a coded bit stream comprising a base layer and one or more enhancement layer. The encoder comprises a base layer quantizer (BLQ) and an enhancement layer quantizer (ELQ) and selects parameters of the BLQ and the ELQ by a joint BLQ-ELQ adaptation method which given a plurality of candidate sets of parameters for the BLQ, for each candidate set, computes a joint BLQ-ELQ distortion value based on a BLQ distortion function, an ELQ distortion function, and at least in part on the number of input pixels to be quantized by the ELQ. The encoder selects as the output BLQ parameter set the candidate set for which the computed joint BLQ-ELQ distortion value is the smallest. Example ELQ, BLQ, and joint BLQ-ELQ distortion functions are provided.

    摘要翻译: 编码器接收要编码在包括基本层和一个或多个增强层的编码比特流中的增强动态范围(EDR)的一个或多个输入图像。 编码器包括基本层量化器(BLQ)和增强层量化器(ELQ),并且通过联合BLQ-ELQ适配方法来选择BLQ和ELQ的参数,该方法为每个BLQ给出了多个用于BLQ的候选参数组 候选集合,基于BLQ失真函数,ELQ失真函数,并且至少部分地基于由ELQ量化的输入像素的数量来计算联合BLQ-ELQ失真值。 编码器选择输出BLQ参数设置计算出的关节BLQ-ELQ失真值最小的候选组。 提供了例如ELQ,BLQ和联合BLQ-ELQ失真功能。

    Error Control in Multi-Stream EDR Video Codec
    60.
    发明申请
    Error Control in Multi-Stream EDR Video Codec 有权
    多流EDR视频编解码器中的错误控制

    公开(公告)号:US20150117551A1

    公开(公告)日:2015-04-30

    申请号:US14514597

    申请日:2014-10-15

    IPC分类号: H04N19/65 H04N19/44

    摘要: Error control in multi-stream visual dynamic range (VDR) codecs is described, including for a case of a layer-decomposed (non-backward compatible) video codecs. Error control can be provided by concealing lost and/or corrupted data in data frames of a decoded VDR bitstream prior to rendering a corresponding VDR image. Various algorithms and methods for concealing lost and/or corrupted data are provided.

    摘要翻译: 描述了多流视觉动态范围(VDR)编解码器中的错误控制,包括对于层分解(非向后兼容)视频编解码器的情况。 可以通过在渲染对应的VDR图像之前隐藏解码的VDR比特流的数据帧中的丢失和/或损坏的数据来提供错误控制。 提供了用于隐藏丢失和/或损坏的数据的各种算法和方法。