Adaptive skip or zero block detection combined with transform size decision

A method, comprising:

• encoding a picture in a video sequence, the picture being formed from blocks, the encoding including encoding of a respective block of the picture by applying a series of skip-block detection procedures during the encoding of the respective block, wherein the series of skip-block detection procedures comprises:
• a first skip-block detection procedure implemented prior to performing any motion estimation for the respective block;
• and
• a second skip-block detection procedure implemented after performing motion estimation for the respective block and if the first skip-block detection procedure fails to detect that the respective block is to be encoded in skip mode.

One or more computer-readable memory or storage devices storing computer-executable instructions which when executed by a computing device causes the computing device to perform encoding operations comprising:

• encoding a picture in a video sequence using a block-based encoding process in which a core transform is applied to one or more blocks of the picture;
• and
• outputting a bitstream including the encoded picture,
• wherein the encoding of the picture in the video sequence comprises, for a current block of the picture being encoded:
• applying transforms of different sizes to the current block;
• determining a transform size of a core transform to be selectively applied during encoding and signaled for use by the decoder based on results of the application of the transforms of different sizes;
• and
• determining whether to encode the current block in a skip mode based on at least some of the results of the application of the transforms of different sizes.