Techniques for error concealment in multimedia data processing. In an embodiment, error distribution information corresponding to a first section in an access unit is obtained. In another embodiment, a plurality of error recovery schemes may be applied to the first section of the multimedia data based on the error distribution information.

If the number of frames in a GOP of an input stream is not less than 15, the GOP is determined as a control unit time. If the number of frames in the GOP is less than 15, the following GOP is connected thereto until the number of frames becomes not less than 15 and the connected GOPs are determined as a control unit time. After correcting the control unit time, the average input bit rate S.sub.n in each control unit time is obtained, and by using information on the input stream including the average input bit rate S.sub.n, a quantization step value of an output stream is calculated.

If the number of frames in a GOP of an input stream is not less than 15, the GOP is determined as a control unit time. If the number of frames in the GOP is less than 15, the following GOP is connected thereto until the number of frames becomes not less than 15 and the connected GOPs are determined as a control unit time. After correcting the control unit time, the average input bit rate S.sub.n in each control unit time is obtained, and by using information on the input stream including the average input bit rate S.sub.n, a quantization step value of an output stream is calculated.

A method performed by a video encoder for encoding a current picture belonging to a temporal level identified by a temporal_id. The method includes determining a Reference Picture Set (RPS) for the current picture indicating reference pictures that are kept in a decoded picture buffer (DPB) when decoding the current picture, and when the current picture is a temporal switching point. The method further comprises operating to ensure that the RPS of the current picture includes no picture having a temporal_id greater than or equal to the temporal_id of the current picture.

A method performed by a video encoder for encoding a current picture belonging to a temporal level identified by a temporal_id. The method includes determining a Reference Picture Set (RPS) for the current picture indicating reference pictures that are kept in a decoded picture buffer (DPB) when decoding the current picture, and when the current picture is a temporal switching point. The method further comprises operating to ensure that the RPS of the current picture includes no picture having a temporal_id greater than or equal to the temporal_id of the current picture.

Approaches to selection of motion vector (“MV”) precision during video encoding are presented. These approaches can facilitate compression that is effective in terms of rate-distortion performance and/or computational efficiency. For example, a video encoder determines an MV precision for a unit of video from among multiple MV precisions, which include one or more fractional-sample MV precisions and integer-sample MV precision. The video encoder can identify a set of MV values having a fractional-sample MV precision, then select the MV precision for the unit based at least in part on prevalence of MV values (within the set) having a fractional part of zero. Or, the video encoder can perform rate-distortion analysis, where the rate-distortion analysis is biased towards the integer-sample MV precision. Or, the video encoder can collect information about the video and select the MV precision for the unit based at least in part on the collected information.

Approaches to selection of motion vector (“MV”) precision during video encoding are presented. These approaches can facilitate compression that is effective in terms of rate-distortion performance and/or computational efficiency. For example, a video encoder determines an MV precision for a unit of video from among multiple MV precisions, which include one or more fractional-sample MV precisions and integer-sample MV precision. The video encoder can identify a set of MV values having a fractional-sample MV precision, then select the MV precision for the unit based at least in part on prevalence of MV values (within the set) having a fractional part of zero. Or, the video encoder can perform rate-distortion analysis, where the rate-distortion analysis is biased towards the integer-sample MV precision. Or, the video encoder can collect information about the video and select the MV precision for the unit based at least in part on the collected information.

Methods and systems are provided for image processing. A plurality of correlation parameters representing degrees of correlation between two or more images of a plurality of images may be determined. An optimized correlation dependency graph may be generated according to the plurality of correlation parameters. The plurality of images may then be delta encoded according to the optimized correlation dependency graph. For example, the optimized correlation dependency graph may be used for performing a predetermined correlation encoding operation. The plurality of correlation parameters may be determined, for example, in accordance with one or more predetermined correlation metrics associated with the predetermined correlation encoding operation.

Methods and systems are provided for image processing. A plurality of correlation parameters representing degrees of correlation between two or more images of a plurality of images may be determined. An optimized correlation dependency graph may be generated according to the plurality of correlation parameters. The plurality of images may then be delta encoded according to the optimized correlation dependency graph. For example, the optimized correlation dependency graph may be used for performing a predetermined correlation encoding operation. The plurality of correlation parameters may be determined, for example, in accordance with one or more predetermined correlation metrics associated with the predetermined correlation encoding operation.

A method and apparatus for encoding surveillance video where one or more regions of interest are identified and the encoding parameter values associated with those regions are specified in accordance with intermediate outputs of a video analytics process. Such an analytics-modulated video compression approach allows the coding process to adapt dynamically based on the content of the surveillance images. In this manner, the fidelity of the region of interest is increased relative to that of a background region such that the coding efficiency is improved, including instances when no target objects appear in the scene. Better compression results can be achieved by assigning different coding priority levels to different types of detected objects.