A method and apparatus for encoding and/or decoding image data. The encoding method includes: if the color space of an image is a single color space, correcting pixel values by applying identical correction pixel values to all color components of a previous image, and if the color space of the image is not a single color space, correcting pixel values by applying different correction pixel values to the color components of the previous image; performing temporal prediction encoding of a current image by using the corrected pixel values of the previous image; quantizing the prediction encoded data; and generating a bitstream by entropy encoding the quantized data. According to the method and apparatus, when the pixel values of a previous image are desired to be corrected in order to perform temporal prediction encoding, different pixel value correction methods are applied according to whether or not the characteristics of color components included in the color space of the image desired to be encoded. By doing so, when image data is encoded, the encoding can be performed adaptively to a variety of color spaces and higher compression efficiency can be maintained.