FIELD OF THE INVENTION

The present invention generally relates to the field of video compression. In particular, the present invention is directed to methods and systems for adaptive cropping.

BACKGROUND

A video codec can include an electronic circuit or software that compresses or decompresses digital video. It can convert uncompressed video to a compressed format or vice versa. In the context of video compression, a device that compresses video (and/or performs some function thereof) can typically be called an encoder, and a device that decompresses video (and/or performs some function thereof) can be called a decoder.

A format of the compressed data can conform to a standard video compression specification. The compression can be lossy in that the compressed video lacks some information present in the original video. A consequence of this can include that decompressed video can have lower quality than the original uncompressed video because there is insufficient information to accurately reconstruct the original video.

There can be complex relationships between the video quality, the amount of data used to represent the video (e.g., determined by the bit rate), the complexity of the encoding and decoding algorithms, sensitivity to data losses and errors, ease of editing, random access, end-to-end delay (e.g., latency), and the like.

Motion compensation can include an approach to predict a video frame or a portion thereof given a reference frame, such as previous and/or future frames, by accounting for motion of the camera and/or objects in the video. It can be employed in the encoding and decoding of video data for video compression, for example in the encoding and decoding using the Motion Picture Experts Group (MPEG)'s advanced video coding (AVC) standard (also referred to as H.264). Motion compensation can describe a picture in terms of the transformation of a reference picture to the current picture. The reference picture can be previous in time when compared to the current picture, from the future when compared to the current picture. When images can be accurately synthesized from previously transmitted and/or stored images, compression efficiency can be improved.

SUMMARY OF THE DISCLOSURE

In an aspect, an encoder includes circuitry configured to receive a video including a current frame, select a cropped sub-frame of the current frame, signal in a bitstream the cropped sub-frame of the current frame as a function of the initial block segment, wherein the cropped sub-frame is signaled using at least a vertical offset and at least a horizontal offset, the at least a vertical offset includes an sps_conf_win_top_offset and an sps_conf_win_bottom offset, the at least a horizontal offset includes an sps_conf_win_left_offset and an sps_conf_win_right_offset, and signal in the bitstream a scaling constant associated with the cropped sub-frame.

In another aspect, a method includes receiving, by an encoder, a video including a current frame, selecting, by the encoder, a cropped sub-frame of the current frame, signaling, by the encoder and in a bitstream the cropped sub-frame of the current frame as a function of the initial block segment, wherein the cropped sub-frame is signaled using at least a vertical offset and at least a horizontal offset, the at least a vertical offset includes an sps_conf_win_top_offset and an sps_conf_win_bottom offset, the at least a horizontal offset includes an sps_conf_win_left_offset and an sps_conf_win_right_offset, and signaling by the encoder and in the bitstream a scaling constant associated with the cropped sub-frame.

The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features and advantages of the subject matter described herein will be apparent from the description and drawings, and from the claims.

