Macroblock based scaling of images using reduced memory bandwidth

Abstract

A method and/or system of scaling images by providing a horizontal macroblock scaler with pixels of the images in units of macroblocks and a vertical macroblock scaler where the pixels of the output image are in units of macroblocks. For the horizontal macroblock scaler macroblocks decoded or vertically scaled are read into the horizontal scaler to generate horizontally scaled macroblocks of pixels. The horizontal scaler need not access data stored in a memory, which reduces the memory bandwidth need for scaling the image. For the vertical macroblock scaler macroblocks decoded or horizontally scaled are read into the vertical scaler from memory to generate vertical scaled macroblocks of pixel. The output of the vertical scaler can be sent directly to an encoder without going through memory first, which reduces the memory bandwidth need for scaling the image. A transcoder parameter may also be provided to scale transcoder parameters such as quantization step sizes and motion vectors that are received from the decoder. The scaled transcoder parameters may be fed to an encoder or a transcoder to encode or transcode the scaled images without motion estimation that is computationally expensive.