1. A method implementable on an encoder for adjusting a coding threshold for encoding a region of an image, wherein the coding threshold determines whether the region should be coded, comprising: encoding, at a first time, a first image representation of the region using first encoding parameters generated by the encoder; encoding, at a second time later than the first time, a second image representation of the region using second encoding parameters generated by the encoder; assessing at least the first and second encoding parameters to determine whether the image is likely stationary; and if the image is likely stationary, adjusting the coding threshold in the encoder for at least a portion of the region.