Sign prediction for block-based video coding

A video decoding apparatus, comprising:

• a memory configured to store a bitstream comprising a set of candidate transform coefficients and a sequence of sign signaling bits for the set of candidate transform coefficients;
• and
• a processor coupled to the memory and configured to perform operations comprising:
• receiving a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients;
• generating a set of predicted signs for the set of candidate transform coefficients associated with a transform block of a video frame;
• decoding the sequence of sign signaling bits based on one or more contexts used to entropy-encode the sequence of sign signaling bits to obtain an indication of correctness of the predicted signs of the respective candidate transform coefficients, wherein a context of the one or more contexts used to entropy-encode a sign signaling bit is determined based on a scan position of a candidate transform coefficient corresponding to the sign signaling bit;
• and
• estimating original signs for the set of candidate transform coefficients based on the set of predicted signs and the sequence of decoded sign signaling bits.

A non-transitory computer-readable storage medium having stored therein a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients, wherein the bitstream is decodable by performing operations comprising:

• receiving a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients;
• generating a set of predicted signs for the set of candidate transform coefficients associated with a transform block of a video frame;
• decoding the sequence of sign signaling bits based on one or more contexts used to entropy-encode the sequence of sign signaling bits to obtain an indication of correctness of the predicted signs of the respective candidate transform coefficients, wherein a context of the one or more contexts used to entropy-encode a sign signaling bit is determined based on a scan position of a candidate transform coefficient corresponding to the sign signaling bit;
• and
• estimating original signs for the set of candidate transform coefficients based on the set of predicted signs and the sequence of decoded sign signaling bits.