Image encoding method and image encoding device

An image encoding method, applied to an image encoding device comprising a first storage region and a second storage region, the image encoding method comprising:

• (a) storing first frame data of a first frame to a first region of the first storage region;
• (b) reading the first frame data from the first region, and using frame data stored in the second storage region as first reference frame data to encode the first frame data which is read to generate first reconstruction data of a first reconstruction frame;
• (c) before the first frame data is completely read from the first region, writing the first reconstruction data to a second region of the first storage region, storage addresses of the first region and the second region partially overlap or completely overlap;
• and
• (d) deleting the frame data in the second storage region, writing second frame data of a second frame to a first region of the second storage region, encoding the second frame data using the first reconstruction data as second reference data to generate second reconstruction data, and then writing the second reconstruction data to a second region of the second storage region.