A decoding system, a RGB video color converter and a method for color conversion of at least part of a decoded currently received YUV frame representing an image is provided. The currently received YUV frame includes image blocks and RGB color conversion is performed by storing a previous color conversion RGB image in a RGB buffer, the image being from an immediately preceding received decoded frame. Next, identifying is effected for identifying the image blocks of the decoded currently received YUV frame that are unchanged relative to corresponding previous image blocks in an immediately preceding received decoded frame. Thereafter, selectively performing YUG to RGB color conversion is effected only on the image blocks of the currently received YUV frame that are not unchanged relative to the corresponding previous image blocks. This provides selected RGB converted blocks for the current frame and then selectively updating image blocks in the buffer with selected RGB converted blocks for the current frame is performed. The resulting RGB image is then displayed on a display module.