Systems for MPEG subsample decoding
First Claim
1. A computer program product for implementing, in a system for processing MPEG data in preparation for displaying video images encoded in the MPEG data, a method for subsampling the MPEG data to reduce the volume of video data processed to selectively display video images based on a reduced volume of video data, the computer program product comprising:
- a computer-readable medium carrying computer executable instructions capable of causing the system to perform the acts ofprocessing the MPEG data to generate a reconstructed digital video stream capable of producing video images in a first video resolution;
receiving a request for displaying video images having a second video resolution;
subsampling the MPEG data to obtain a reduced volume reconstructed digital video stream corresponding to the second video resolution that is less than the first video resolution, wherein the subsampled MPEG data is subsampled without generating a version of the subsampled data in the first video resolution, wherein subsampling includes decimating IDCT output data by a selected factor to generate decimated IDCT output data, and wherein decimating the IDCT output data includes weighting color parameters of at least first and second IDCT output data samples using at least first and second weighting factors, respectively, and summing the weighted color parameters; and
selectively presenting either or both of the first and second reconstructed digital video streams.
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Accused Products
Abstract
Decimating MPEG or other video data by subsampling the output of an inverse discrete cosine transform (IDCT) module. The decimation process is useful for reducing the volume of data that must be processed to display images on a display device, particularly when the volume of video data received at the decoder is greater than the amount needed to take advantage of the resolution of the display device. For example, high definition television data can be decimated for display on a standard television display device or in a picture-in-picture window, thereby reducing the amount of processing resources needed at the decoder and reducing the size of the frame buffers. Subsampling the output of the IDCT module reduces the volume of data and, for relatively static or constant pans, there is not a significant compounded loss of image quality as successive frames are decoded.
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Citations
7 Claims
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1. A computer program product for implementing, in a system for processing MPEG data in preparation for displaying video images encoded in the MPEG data, a method for subsampling the MPEG data to reduce the volume of video data processed to selectively display video images based on a reduced volume of video data, the computer program product comprising:
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a computer-readable medium carrying computer executable instructions capable of causing the system to perform the acts of processing the MPEG data to generate a reconstructed digital video stream capable of producing video images in a first video resolution; receiving a request for displaying video images having a second video resolution; subsampling the MPEG data to obtain a reduced volume reconstructed digital video stream corresponding to the second video resolution that is less than the first video resolution, wherein the subsampled MPEG data is subsampled without generating a version of the subsampled data in the first video resolution, wherein subsampling includes decimating IDCT output data by a selected factor to generate decimated IDCT output data, and wherein decimating the IDCT output data includes weighting color parameters of at least first and second IDCT output data samples using at least first and second weighting factors, respectively, and summing the weighted color parameters; and selectively presenting either or both of the first and second reconstructed digital video streams. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification