Patent ID: 11956457
Assignee: TENCENT AMERICA LLC
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 19:
20. A method for determining bitstream conformance:
receiving an encoded bitstream, wherein the bitstream includes:
a first flag, in an access unit delimiter of the encoded bitstream, that indicates whether an access unit of video data of the encoded bitstream includes either or neither one from among an intra random access point (IRAP) picture and a gradual decoding refresh (GDR) picture,
a second flag, in a picture header of video data of the encoded bitstream, that indicates whether the picture is the IRAP picture, and
a value of the first flag and a value of the second flag are aligned; and

checking bitstream conformance, for references pictures in a reference picture list having an unavailable reference picture, that the following constraints apply:
a number of entries that are indicated to be in the reference picture list is not less than a number of active entries that are indicated to be in the reference picture list,
each picture referred to by an active entry in the reference picture list is present in a decoded picture buffer (DPB) and has a temporal identifier value less than or equal to a temporal identifier value of the current picture, and
each picture referred to by an entry in the reference picture list is not the current picture and is indicated by a picture header flag to potentially be a reference picture.