Block partitioning image and video data

1 . A video coding method comprising:

receiving data for a block of pixels to be encoded or decoded as a current block of a current picture of a video sequence;

determining a flag corresponding to a first condition or a second condition;

determining a maximum multi-type tree (MTT) depth for each of a plurality of possible quadtree (QT) partitioning depths or determining a maximum MTT depth for the current picture;

partitioning the current block by QT partitioning recursively into one or more QT partitions at one or more QT depths;

partitioning a first QT partition by MTT partitioning into MTT partitions, wherein the MTT partitioning is limited by the maximum MTT depth determined for the QT depth of the first QT partition when the flag corresponds to the first condition, and the MTT partitioning is limited by the maximum MTT depth determined for the current picture when the flag corresponds to the second condition; and

reconstructing the QT and MTT partitions of the current block.

2 . The video coding method of claim 1 , wherein:

when the first QT partition is at a first QT level, the MTT partitioning is limited by a first maximum MTT depth; and

when the first QT partition is at a second QT level, the MTT partitioning is limited by a second maximum MTT depth.

3 . The video coding method of claim 1 , wherein the maximum MTT depths for a luma component and maximum MTT depths for a chroma component are determined separately.

4 . The video coding method of claim 1 , wherein the maximum MTT depths for binary tree (BT) partitioning and maximum MTT depths for ternary tree (TT) partitioning are determined separately.

5 . The video coding method of claim 1 , wherein the maximum MTT depths for inter and intra slices are determined separately.

6 . The video coding method of claim 1 , further comprising signaling or receiving syntax elements specifying a maximum MTT depth for each of the multiple QT depths.

7 . The video coding method of claim 6 , wherein the syntax elements specifying the maximum MTT depths are signaled in a picture header of the current picture, a sequence parameter set of the video sequence, or a slice header of a current slice that includes the current block.

8 . The video coding method of claim 6 , wherein the maximum MTT depths are signaled in a lower-level syntax element by indicating that the maximum MTT depths are derived from a higher-level syntax element.

9 . The video coding method of claim 6 , wherein maximum MTT depths signaled in a lower-level syntax element override MTT depths signaled in a higher-level syntax element.

10 . The video coding method of claim 1 , further comprising signaling or receiving a syntax element indicating whether to allow to apply the different maximum MTT depths for the plurality of possible QT depths.

11 . The video coding method of claim 1 , further comprising deriving the maximum MTT depth specified for a first QT depth from the maximum MTT depth specified for a second QT depth.

12 . An electronic apparatus comprising:

a video coder circuit configured to perform operations comprising:

receiving data for a block of pixels to be encoded or decoded as a current block of a current picture of a video sequence;

determining a flag corresponding to a first condition or a second condition;

determining a maximum multi-type tree (MTT) depth for each of a plurality of possible quadtree (QT) partitioning depths or determining a maximum MTT depth for the current picture;

partitioning the current block by QT partitioning recursively into one or more QT partitions at one or more QT depths;

partitioning a first QT partition by MTT partitioning into MTT partitions, wherein the MTT partitioning is limited by the maximum MTT depth determined for the QT depth of the first QT partition when the flag corresponds to the first condition, and the MTT partitioning is limited by the maximum MTT depth determined for the current picture when the flag corresponds to the second condition; and

reconstructing the QT and MTT partitions of the current block.

13 . A video decoding method comprising:

receiving data for a block of pixels to be decoded as a current block of a current picture of a video sequence;

determining a flag corresponding to a first condition or a second condition;

receiving a maximum multi-type tree (MTT) depth for each of a plurality of possible quadtree (QT) partitioning depths or determining a maximum MTT depth for the current picture;

partitioning the current block by QT partitioning recursively into one or more QT partitions at one or more QT depths;

partitioning a first QT partition by MTT partitioning into MTT partitions, wherein the MTT partitioning is limited by the maximum MTT depth received for the QT depth of the first QT partition when the flag corresponds to the first condition, and the MTT partitioning is limited by the maximum MTT depth determined for the current picture when the flag corresponds to the second condition; and

reconstructing the QT and MTT partitions of the current block.

14 . A video encoding method comprising:

receiving data for a block of pixels to be encoded as a current block of a current picture of a video sequence;

determining a flag corresponding to a first condition or a second condition;

specifying a maximum multi-type tree (MTT) depth for each of a plurality of possible quadtree (QT) partitioning depths or determining a maximum MTT depth for the current picture;

partitioning the current block by QT partitioning recursively into one or more QT partitions at one or more QT depths;

partitioning a first QT partition by MTT partitioning into MTT partitions, wherein the MTT partitioning is limited by the maximum MTT depth specified for the QT depth of the first QT partition when the flag corresponds to the first condition, and the MTT partitioning is limited by the maximum MTT depth determined for the current picture when the flag corresponds to the second condition; and

encoding the QT and MTT partitions of the current block.