Macroblock based scaling of images using reduced memory bandwidth

摘要

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.

主权项

1. A method of scaling resolution of an image, comprising:
responsive to receiving first input pixel data for upscaling vertically and horizontally:
storing the first input pixel data in a memory;sending a block of pixels of the first input pixel data from the memory to a vertical scaler;generating, at the vertical scaler, first scaled pixel data representing the block of pixels upscaled vertically compared to the block of pixels;receiving, at a horizontal scaler via a first input of a multiplexer, two or more macroblocks of the first scaled pixel data from the vertical scaler without storing the first scaled pixel data in the memory;generating second scaled pixel data by filtering pixel data for a plurality of pixels spanning across the two or more macroblocks of the first scaled pixel data at a scaling filter in the horizontal scaler, the second scaled pixel data representing a block of pixels upscaled horizontally compared to the two or more macroblocks of the first scaled pixel data; andgenerating a vertically and horizontally upscaled version of the image based on the second scaled pixel data; and responsive to receiving second input pixel data for horizontal scaling without vertical scaling:
receiving, at the horizontal scaler via a second input of the multiplexer, two or more macroblocks of the second input pixel data;generating third scaled pixel data by filtering pixel data for a plurality of pixel data spanning across the two or more macroblocks of the second input pixel data, the third scaled pixel data representing a block of pixels scaled horizontally compared to the two or more macroblocks of the second input pixel data; andgenerating a horizontally scaled version of the image based on the third scaled pixel data.