Signaling macroblock mode information for macroblocks of interlaced forward-predicted fields
AssigneeMicrosoft Corporation
InventorsThomas W. Holcomb, Pohsiang Hsu, Sridhar Srinivasan, Chih-Lung Lin
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Abstract
Techniques and tools for code table selection and joint coding/decoding of macroblock mode information for macroblocks of interlaced forward-predicted frames are described. For example, a video decoder decodes a variable length code that jointly signals macroblock mode information for a motion-compensated macroblock. The jointly signaled information includes a macroblock type, whether a coded block pattern is present or absent, and whether motion vector data is present or absent for the motion-compensated macroblock. A video encoder performs corresponding encoding.
Claims20
In a computing device that implements a video decoder, the computing device comprising a processor and memory, a method of transforming encoded video information, the method comprising:
- receiving, at the computing device that implements the video decoder, encoded video information in a bit stream;
- and
- with the computing device that implements the video decoder, decoding an interlaced forward-predicted field using the encoded video information, including processing a variable length code that jointly signals macroblock mode information for a macroblock of the interlaced forward-predicted field, wherein the macroblock is motion-compensated, and wherein the jointly signaled macroblock mode information is one of plural combinations of options for (1) a macroblock type, (2) whether a coded block pattern is present or absent, and (3) whether motion vector data is present or absent for the motion-compensated macroblock of the interlaced forward-predicted field, the plural combinations including at least one combination in which the coded block pattern is absent for the motion-compensated macroblock of the interlaced forward-predicted field.
In a computing device that implements a video encoder, the computing device comprising a processor and memory, a method of transforming video information, the method comprising:
- with the computing device that implements the video encoder, encoding a current interlaced forward-predicted field to produce encoded video information, including:
- selecting a code table from among plural available code tables for macroblock mode information for interlaced forward-predicted fields;
- and
- using the selected code table to process a variable length code that indicates macroblock mode information for a macroblock, wherein the macroblock mode information includes (1) a macroblock type, (2) whether a coded block pattern is present or absent, and (3) when applicable for the macroblock type, whether motion vector data is present or absent;
- and
- from the computing device that implements the video encoder, outputting the encoded video information in a bit stream.
A video decoder comprising:
- a processor;
- memory;
- at least one input device, output device or communication connection;
- and
- storage storing computer-executable instructions for causing the video decoder to decode video using:
- means for decoding plural variable length codes, each of the plural variable length codes jointly signaling macroblock mode information for one of plural macroblocks of an interlaced P-field, wherein for each of the plural macroblocks the macroblock mode information includes a macroblock type and, regardless of the macroblock type, a first presence indicator for presence or absence of a coded block pattern, and wherein for at least one motion-compensated macroblock of the plural macroblocks the macroblock mode information further includes a second presence indicator for presence or absence of motion vector data for the motion-compensated macroblock of the interlaced P-field;
- and
- means for performing motion compensation.
Dependencies are inferred from the claim text.