An image processing apparatus, the apparatus comprising: a processing resource (102, 112, 114) comprising a processor and an image processing unit, IPU, (112, 114) arranged to transfer image data to a main frame buffer for output by a display device; a first frame buffer for storing first image data (204, 206, 208, 210, 216), the first image data (204, 206, 208, 210, 216) comprising background objects and foreground objects, the background objects including a video window, the first image data (204, 206, 208, 210, 216) having a first frame rate associated therewith; a second frame buffer for storing second image data, the second image data having a second frame rate associated therewith, wherein the second frame rate is higher than the first frame rate; the processing resource (102, 112, 114) arranged to acquire a location of the video window; the processing resource (102, 112, 114) supporting a masking process and arranged to incorporate mask data into the first image data (204, 206, 208, 210, 216) in the first frame buffer by filling a reserved output area bounded by the video window and not obscured by the foreground objects with a predefined keycolor; and the image processing unit, IPU, (112, 114) supporting 2D DMA data transfer on a pixel-by-pixel basis and arranged to transfer the first image data (204, 206, 208, 210, 216) and at least part of second image data to the main frame buffer wherein the mask data is used by the masking process in relation to the second image data in order to provide the at least part of the second image data in place of the mask data such that the at least part of the second image data occupies the reserved output area, wherein the image processing apparatus, IPU, (112, 114) is characterized in that the image processing unit, IPU, (112, 114) is further arranged to retrieve a pixel of the first image data (204, 206, 208, 210, 216) from the first frame buffer; if the retrieved pixel of the first image data (204, 206, 208, 210, 216) is encountered within the video window using the acquired location of the video window and has the predefined keycolor, to retrieve a corresponding pixel of the second image data from the second frame buffer and to transfer the retrieved pixel of the second image data to the main frame buffer; and otherwise, to transfer the retrieved pixel of the first image data (204, 206, 208, 210, 216) to the main frame buffer. a processing resource (102, 112, 114) comprising a processor and an image processing unit, IPU, (112, 114) arranged to transfer image data to a main frame buffer for output by a display device; a first frame buffer for storing first image data (204, 206, 208, 210, 216), the first image data (204, 206, 208, 210, 216) comprising background objects and foreground objects, the background objects including a video window, the first image data (204, 206, 208, 210, 216) having a first frame rate associated therewith; a second frame buffer for storing second image data, the second image data having a second frame rate associated therewith, wherein the second frame rate is higher than the first frame rate; the processing resource (102, 112, 114) arranged to acquire a location of the video window; the processing resource (102, 112, 114) supporting a masking process and arranged to incorporate mask data into the first image data (204, 206, 208, 210, 216) in the first frame buffer by filling a reserved output area bounded by the video window and not obscured by the foreground objects with a predefined keycolor; and the image processing unit, IPU, (112, 114) supporting 2D DMA data transfer on a pixel-by-pixel basis and arranged to transfer the first image data (204, 206, 208, 210, 216) and at least part of second image data to the main frame buffer wherein the mask data is used by the masking process in relation to the second image data in order to provide the at least part of the second image data in place of the mask data such that the at least part of the second image data occupies the reserved output area, wherein the image processing apparatus, IPU, (112, 114) is characterized in that the image processing unit, IPU, (112, 114) is further arranged to retrieve a pixel of the first image data (204, 206, 208, 210, 216) from the first frame buffer; if the retrieved pixel of the first image data (204, 206, 208, 210, 216) is encountered within the video window using the acquired location of the video window and has the predefined keycolor, to retrieve a corresponding pixel of the second image data from the second frame buffer and to transfer the retrieved pixel of the second image data to the main frame buffer; and otherwise, to transfer the retrieved pixel of the first image data (204, 206, 208, 210, 216) to the main frame buffer.