Sign hiding techniques for quantized transform coefficients in video coding

A method for encoding video data, the method comprising:

• generating a block of transform coefficients, wherein the block of transform coefficients is one coefficient group of a plurality of coefficient groups of a transform block;
• determining whether to perform a sign data hiding process for a first transform coefficient in the one coefficient group based on a first variable compared to a first threshold;
• determining whether to perform a sign data hiding process for a second transform coefficient in the one coefficient group based on a second variable compared to a second threshold different from the first threshold;
• encoding sign information for the block based on the determination of whether to perform the sign data hiding process;
• and
• encoding the video data based on the transform coefficients.

An apparatus configured to code video data, the apparatus comprising:

• a memory configured to store a transform block of transform coefficients;
• and
• a video coding processor configured to:
• determine a block of transform coefficients, wherein the block of transform coefficients is one coefficient group of a plurality of coefficient groups of a transform block;
• determine whether to perform a sign data hiding process for a first transform coefficient in the one coefficient group based on a first variable compared to a first threshold;
• determine whether to perform a sign data hiding process for a second transform coefficient in the one coefficient group based on a second variable compared to a second threshold different from the first threshold;
• code sign information for the block based on the determination of whether to perform the sign data hiding process;
• and
• code the video data based on the transform coefficients.

An apparatus configured to code video data, the apparatus comprising:

• means for determining a block of transform coefficients, wherein the block of transform coefficients is one coefficient group of a plurality of coefficient groups of a transform block;
• means for determining whether to perform a sign data hiding process for a first transform coefficient in the one coefficient group based on a first variable compared to a first threshold;
• means for determining whether to perform a sign data hiding process for a second transform coefficient in the one coefficient group based on a second variable compared to a second threshold different from the first threshold;
• means for coding sign information for the block based on the determination of whether to perform the sign data hiding process;
• and
• means for coding the video data based on the transform coefficients.

A non-transitory computer-readable storage medium storing instructions that, when executed, cause one or more processors of a device configured to code video data to:

• determine a block of transform coefficients, wherein the block of transform coefficients is one coefficient group of a plurality of coefficient groups of a transform block;
• determine whether to perform a sign data hiding process for a first transform coefficient in the one coefficient group based on a first variable compared to a first threshold;
• determine whether to perform a sign data hiding process for a second transform coefficient in the one coefficient group based on a second variable compared to a second threshold different from the first threshold;
• code sign information for the block based on the determination of whether to perform the sign data hiding process;
• and
• code the video data based on the transform coefficients.