摘要:
In a scalable video codec, an adaptive Wiener filter with offset aims to minimize the differences between two input pictures or picture regions, and the filter coefficients need to be transmitted to decoder site.
摘要:
Adaptive control can use hierarchical motion estimation (HME) and/or multiple reference motion estimation (MRME) for the motion estimation of current encoding blocks. Both HME and MRME are allowed in the motion estimation to achieve a high coding gain. Control consists of slice level control and macro-block (MB) level control. A slice is one or more contiguous macroblocks. In slice level control, it is decided to use only one reference frame or use multiple reference frames to coding current slice based on the motion vectors obtained in coarse level motion estimation. In MB level control, it is decided to perform MRME or perform HME for the MB and its subblocks based on the coarse level motion vectors of the MB.
摘要:
Systems, devices and methods are described including performing scalable video coding using inter-layer residual prediction, inter-layer residual prediction in an enhancement layer coding unit, prediction unit, or transform unit may use residual data obtained from a base layer or from a lower enhancement layer. The residual may be subjected to upsample filtering and/or refinement filtering. The upsample or refinement filter coefficients may be predetermined or may be adoptively determined.
摘要:
Systems, apparatus and methods are described including determining a prediction residual for a channel of video data; and determining, using the first channel's prediction residual, a prediction residual for a second channel of the video data. Further, a prediction residual for a third channel of the video data may be determined using the second channel's prediction residual.
摘要:
Reconstructed picture quality for a video codec system may be improved by categorizing reconstructed pixels into different histogram bins with histogram segmentation and then applying different filters on different bins. Histogram segmentation may be performed by averagely dividing the histogram into M bins or adaptively dividing the histogram into N bins based on the histogram characteristics. Here M and N may be a predefined, fixed, non-negative integer value or an adaptively generated value at encoder side and may be sent to decoder through the coded bitstream.
摘要:
Methods and systems to apply motion estimation (ME) based on reconstructed reference pictures in a B frame or in a P frame at a video decoder. For a P frame, projective ME may be performed to obtain a motion vector (MV) for a current input block. In a B frame, both projective ME and mirror ME may be performed to obtain an MV for the current input block. The ME process can be performed on sub-partitions of the input block, which may reduce the prediction error without increasing the amount of MV information in the bitstream. Decoder-side ME can be applied for the prediction of existing inter frame coding modes, and traditional ME or the decoder-side ME can be adaptively selected to predict a coding mode based on a rate distribution optimization (RDO) criterion.
摘要:
Techniques are described that can be used to apply motion estimation (ME) based on reconstructed reference pictures in a B frame or in a P frame at a video decoder. For a P frame, projective ME may be performed to obtain a motion vector (MV) for a current input block. In a B frame, both projective ME and mirror ME may be performed to obtain an MV for the current input block. A metric an be used determining a metric for each pair of MV0 and MV1 that is found in the search path, where the metric is based on a combination of a first, second, and third metrics. The first metric is based on temporal frame correlation, a second metric is based on spatial neighbors of the reference blocks, and a third metric is based on the spatial neighbors of the current block.
摘要:
Techniques are described that can be used to determine parameters of an adaptive Wiener filter to apply to a video region. The following parameters of the Wiener filter may be adjusted: coefficients, coefficient quantization, filter type, filter size, prediction mode, entropy encoding, and number of filter tables. The parameters associated with the lowest rate distortion cost of the encoder are selected for transmission with the encoded video. If not using adaptive Wiener filtering results in a lowest rate distortion cost, then adaptive Wiener filtering is not used for the video region. If using adaptive Wiener filtering results in a lowest rate distortion cost, then the parameters applied by the adaptive Wiener filtering that result in the lowest rate distortion cost are communicated with the filtered video region.
摘要:
To let decoder side motion vector derivation (DMVD) coded blocks be decoded in parallel, decoder side motion estimation (ME) dependency on spatially neighboring reconstructed pixels can be removed. Mirror ME and projective ME are only performed on two reference pictures, and the spatially neighboring reconstructed pixels will not be considered in the measurement metric of the decoder side ME. Also, at a video decoder, motion estimation for a target block in a current picture can be performed by calculating a motion vector for a spatially neighboring DMVD block, using the calculated motion vector to predict motion vectors of neighboring blocks of the DMVD block, and decoding the DMVD block and the target block in parallel. In addition, determining a best motion vector for a target block in a current picture can be performed by searching only candidate motion vectors in a search window, wherein candidate motion vectors are derived from a small range motion search around motion vectors of neighboring blocks.