Coding of significance maps and transform coefficient blocks

An apparatus for encoding a video into a data stream, the apparatus comprising:

• an encoder configured to encode, based on context-adaptive entropy encoding, first-type syntax elements and second-type syntax elements, wherein each of the first-type syntax elements indicates whether at a respective position corresponding to the first-type syntax element within a transform coefficient block, a significant transform coefficient is present, and each of the second-type syntax elements relates to a value of the significant transform coefficient at a respective position corresponding to the second-type syntax element within the transform coefficient block;
• wherein the encoder is configured to context-adaptive entropy encode the first-type syntax elements in a scan order determined from among a plurality of scan orders, and for context-adaptive entropy encoding of a current first-type syntax element of the first-type syntax elements, the encoder is configured to use a context that is selected for the current first-type syntax element based on the scan order and a transform block size.

A non-transitory computer-readable medium for storing data associated with a video, comprising:

• a data stream stored in the non-transitory computer-readable medium, the data stream comprising first-type syntax elements and second-type syntax elements, wherein each of the first-type syntax elements indicates whether at a respective position corresponding to the first-type syntax element within a transform coefficient block, a significant transform coefficient is present, and each of the second-type syntax elements relates to a value of the significant transform coefficient at a respective position corresponding to the second-type syntax element within the transform coefficient block,
• wherein the first-type syntax elements are decoded in a scan order, which is determined from among a plurality of scan orders, and based on context-adaptive entropy decoding using contexts which are selected for each of the first-type syntax elements, wherein the context for a current first-type syntax element being decoded is selected in accordance with the scan order and a transform block size.