Unified intra block copy and inter prediction modes

In a computer system that implements a video decoder, a method comprising:

• receiving encoded data in a bitstream, the encoded data including a first flag that indicates whether intra block copy (IBC) prediction mode is enabled or disabled, wherein the first flag is part of a sequence parameter set;
• and
• decoding a current picture using at least part of the encoded data, the current picture including multiple blocks, wherein the decoding the current picture includes:
• determining a second flag that applies for a current block among the multiple blocks, the second flag indicating a prediction mode for the current block is the IBC prediction mode;
• determining a vector for the current block, the vector indicating a displacement within the current picture, including, as part of merge mode processing:
• determining a set of merge mode candidates, including, for each of multiple candidates:
• (a) obtaining the candidate, and (b) if the candidate references the current picture, retaining the candidate in the set of merge mode candidates, but otherwise, the candidate not referencing the current picture, excluding the candidate from the set of merge mode candidates;
• and
• selecting, as the vector for the current block, one of the set of merge mode candidates;
• and
• performing IBC prediction for the current block using the vector.

A computer system comprising a processor and memory, wherein the computer system implements a video encoder configured to perform operations comprising:

• determining whether to enable or disable intra block copy (IBC) prediction mode;
• setting a first flag to indicate whether the IBC prediction mode is enabled or disabled;
• encoding a current picture that includes multiple blocks, wherein the encoding the current picture includes:
• determining that a prediction mode for a current block among the multiple blocks is the IBC prediction mode, wherein a second flag, which applies for the current block, indicates the prediction mode for the current block is the IBC prediction mode;
• determining a vector for the current block, the vector indicating a displacement within the current picture, including, as part of merge mode processing:
• determining a set of merge mode candidates, including, for each of multiple candidates:
• (a) obtaining the candidate, and (b) if the candidate references the current picture, retaining the candidate in the set of merge mode candidates, but otherwise, the candidate not referencing the current picture, excluding the candidate from the set of merge mode candidates;
• and
• selecting, as the vector for the current block, one of the set of merge mode candidates;
• and
• performing IBC prediction for the current block using the vector;
• and
• outputting encoded data as part of a bitstream, the encoded data including the first flag as part of a sequence parameter set.

One or more computer-readable media having stored thereon encoded data in a bitstream, the encoded data including a first flag that indicates whether intra block copy (IBC) prediction mode is enabled or disabled, wherein the first flag is part of a sequence parameter set for a video sequence, the video sequence including a current picture that includes multiple blocks, the encoded data being organized to facilitate decoding the current picture with a video decoder by operations comprising:

• determining a second flag that applies for a current block among the multiple blocks, the second flag indicating a prediction mode for the current block is the IBC prediction mode;
• determining a vector for the current block, the vector indicating a displacement within the current picture, including, as part of merge mode processing:
• determining a set of merge mode candidates, including, for each of multiple candidates:
• (a) obtaining the candidate, and (b) if the candidate references the current picture, retaining the candidate in the set of merge mode candidates, but otherwise, the candidate not referencing the current picture, excluding the candidate from the set of merge mode candidates;
• and
• selecting, as the vector for the current block, one of the set of merge mode candidates;
• and
• performing IBC prediction for the current block using the vector.