Rotational transcoding for JPEG or other coding standards

摘要

This disclosure describes techniques for rotating an encoded image, such as an image encoded according to a JPEG standard. In one example, a method for rotating an encoded image comprising reordering minimum coded units (MCUs) of the encoded image according to a specified rotation of the encoded image, rotating image data within the MCUs according to the specified rotation, and generating a rotated version of the encoded image comprising the reordered MCUs and the rotated image data within the MCUs.

主权项

1. A method in an image capture device for rotating an encoded image comprising:
reordering minimum coded units (MCUs) of the encoded image according to a specified rotation of the encoded image, wherein the MCUs are separately decodable units that are decoded without reference to another MCU; applying file size control parameters to image data within the MCUs by reducing or eliminating high frequency components within the MCUs; rotating the image data within the MCUs according to the specified rotation comprising performing a flip operation on coefficient values of the MCUs; and generating the rotated version of the encoded image comprising the reordered MCUs and the rotated image data within the MCUs, wherein reordering MCUs, rotating image data within the MCUs, and generating a rotated version of the encoded image are accomplished by the image capture device.