Soft decision and iterative video coding for MPEG and H.264
AssigneeResearch In Motion Limited
InventorsEn-Hui Yang, Xiang Yu
Life of this patent
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Abstract
A method of encoding video data using soft decision quantization makes use of iterative encoding to provide the ability to optimize encoding across different functional elements in a hybrid video encoder. Iterative encoding is used to allow quantization step size, motion prediction and quantization levels to be optimized despite their interrelated nature.
Claims30
A method for obtaining an optimal sequence of quantized coefficients for a block of transform residuals from a video, for encoding the video in a video encoder, the method comprising:
- constructing a graph representing a plurality of sequences of quantized coefficients for the block of transform residuals, wherein each node in the graph includes a rate cost determined from a context in a context-adaptive entropy encoder;
- and
- selecting in said graph a sequence of quantized coefficients that has a minimum rate-distortion cost, wherein rate-distortion cost is based on distortion cost and rate cost, and wherein rate cost is based on the context-adaptive entropy encoder, wherein the context-adaptive entropy encoder defines a plurality of contexts, and wherein entropy encoding of an element of a quantized coefficient is dependent upon selection of one of the contexts for that element.
A Apparatus for obtaining an optimal sequence of quantized coefficients for a block of transform residuals from a video, for encoding the video in a video encoder, the method comprising:
- constructing a graph representing a plurality of sequences of quantized coefficients for the block of transform residuals, wherein each node in the graph includes a rate cost determined from a context in a context-adaptive entropy encoder;
- and
- selecting in said graph a sequence of quantized coefficients that has a minimum rate-distortion cost, wherein rate-distortion cost is based on distortion cost and rate cost, and wherein rate cost is based on the context-adaptive entropy encoder, wherein the context-adaptive entropy encoder defines a plurality of contexts, and wherein entropy encoding of an element of a quantized coefficient is dependent upon selection of one of the contexts for that element.
A non-transitory computer-readable medium embodying computer-executable instructions for obtaining an optimal sequence of quantized coefficients for a block of transform residuals from a video, for encoding the video in a video encoder, the method comprising:
- constructing a graph representing a plurality of sequences of quantized coefficients for the block of transform residuals, wherein each node in the graph includes a rate cost determined from a context in a context-adaptive entropy encoder;
- and
- selecting in said graph a sequence of quantized coefficients that has a minimum rate-distortion cost, wherein rate-distortion cost is based on distortion cost and rate cost, and wherein rate cost is based on the context-adaptive entropy encoder,
- wherein the context-adaptive entropy encoder defines a plurality of contexts, and wherein entropy encoding of an element of a quantized coefficient is dependent upon selection of one of the contexts for that element.
Dependencies are inferred from the claim text.