On December 5, the US Patent & Trademark Office published Apple’s newly granted patent for ‘Dynamic selection of field/frame-based MPEG video encoding.’ Apple’s patent relates to video encoding. More specifically, the invention relates to dynamic selection between field-based encoding and frame-based encoding for Motion Picture Experts Group (MPEG) video encoding.
Dynamic selection of field/frame-based MPEG video encoding
Abstract: A discrete cosine transform (DCT) level enhancement to Motion Picture Experts Group (MPEG) video encoding is described that results in a more concise bitstream than MPEG encoding without the enhancement. One degree of freedom provided by the MPEG encoding specifications is whether a frame- or field-based DCT operation will be used. In the field-based DCT operations, luminance sub-blocks are built from even or odd rows of the original image, which correspond to the top and bottom fields in field-based video. This allows the encoder to take advantage of the higher correlation between rows for the same field, especially in field-based video with a high level of motion. In one embodiment, both field- and frame-based DCT operations are performed and the results are quantized. On a macroblock-by-macroblock basis, the option that results in the fewest non-zero coefficients is selected and those coefficients are used for run-time encoding.
In Patent FIG. 2 Apple illustrates a block diagram of a MPEG encoding scheme in which selection between field- or frame-based DCT operations is performed dynamically during encoding. The various components of the block diagram of FIG. 2 can be implemented as hardware, software or a combination of hardware and software. Thus, the selection of whether a macroblock is to be processed using field- or frame-based DCT operations as well as other portions of MPEG encoding can be any combination of hardware and software.
Inventor/Filing Date: The sole inventor is listed as Jason Klivington. The original filing date is noted as being January 2002.
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Written and researched by Neo.