Image decoding device and still frame image decoding method thereof

An image decoding device, comprising:

• a video receiving circuit, configured to receive a plurality of video data corresponding to different channels;
• an image adjusting circuit;
• and
• a decoder, configured to:
• decode a first frame in first video data of a plurality of video data according to a reference frame at a reference location of a memory, and store the first frame to the reference location to overwrite at least one part of the reference frame;
• select the first video data from the plurality of video data and decode a second frame in the first video data according to the first frame at the reference location in response to a still frame command, wherein the image adjusting module adjusts the second frame and stores the adjusted second frame to an output location of the memory;
• preserve the first frame at the reference location in response to the still frame command so as to again decode the second frame according to the first frame at the reference location;
• and
• again decode the second frame according to the first frame at the reference location in response to an end command, so as to store the second frame to the reference location to overwrite at least one part of the first frame.