Dependent random access point pictures

A method for encoding a video bitstream comprising:

• encoding an intra random access point, IRAP, picture of said video bitstream;
• encoding a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and the random access point identifying a location other than a beginning of said video bitstream where to start decoding said video bitstream, and
• encoding at least one non-random access point, non-RAP, picture of said video stream following said DRAP picture in output order and decoding order, said at least one non-RAP picture is encoded to not allow use of any non-RAP picture preceding said DRAP picture in decoding order in said video stream as reference picture,
• wherein encoding the DRAP picture comprises:
• generating data to accompany said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• encoding the DRAP picture using the generated data.

A decoder for decoding a video bitstream, the decoder comprising:

• at least one processor configured through program code executable from at least one memory to perform operations comprising:
• decoding an intra random access point, IRAP, picture of said video bitstream;
• decoding a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the sole reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and identifies a location other than a beginning of said video bitstream where to start decoding said video bitstream;
• and
• decoding at least one non-random access point, non-RAP, picture of said video bitstream following said DRAP picture in output order and decoding order, said at least one non-RAP picture is encoded to not allow use of any non-RAP picture preceding said DRAP picture in decoding order in said video bitstream as a reference picture,
• wherein decoding the DRAP picture comprises:
• identifying data accompanying said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• decoding the DRAP picture using the identified data accompanying said DRAP picture.

A decoder for decoding a video bitstream comprising:

• at least one processor configured through program code executable from at least one memory to perform operations comprising:
• decoding an intra random access point, IRAP, picture of said video bitstream;
• and
• decoding a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the sole reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and identifies a location other than a beginning of said video bitstream where to start decoding said video bitstream;
• and
• wherein non-RAP pictures of the pictures following said DRAP picture in decoding order are encoded to not allow use of any non-RAP picture preceding said DRAP picture in decoding order in said video bitstream as a reference picture;
• wherein decoding the DRAP picture comprises:
• identifying data accompanying said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• decoding the DRAP picture using the identified data accompanying said DRAP picture.

An encoder for encoding a video stream, the encoder comprising:

• at least one processor configured through program code executable from at least one memory to perform operations comprising:
• encoding an intra random access point, IRAP, picture of said video bitstream;
• encoding a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and the random access point identifying a location other than a beginning of said video bitstream where to start decoding said video bitstream, and
• encoding at least one non-random access point, non-RAP, picture of said video stream following said DRAP picture in output order and decoding order, said at least one non-RAP picture is encoded to not allow use of any non-RAP picture preceding said DRAP picture in decoding order in said video stream as reference picture,
• wherein encoding the DRAP picture comprises:
• generating data to accompany said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• encoding the DRAP picture using the generated data.

An encoder for encoding a video stream comprising:

• at least one processor configured through program code executable from at least one memory to perform operations comprising:
• encoding an intra random access point, IRAP, picture of said video stream;
• and
• encoding a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and the random access point identifying a location other than a beginning of said video bitstream where to start decoding said video bitstream;
• and
• wherein non-RAP pictures of the pictures following said DRAP picture in decoding order are encoded to not allow use of any non-RAP picture preceding said DRAP picture in decoding order in said video bitstream as a reference picture,
• wherein encoding the DRAP picture comprises:
• generating data to accompany said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• encoding the DRAP picture using the generated data.

A non-transitory computer readable medium storing computer program comprising instructions, which when executed by at least one processor, cause said at least one processor to:

• decode an intra random access point, IRAP, picture of said video bitstream;
• decode a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the sole reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and identifies a location other than a beginning of said video bitstream where to start decoding said video bitstream;
• and
• decode at least one non-random access point, non-RAP, picture of said video bitstream following said DRAP picture in output order and decoding order, said at least one non-RAP picture is encoded to not allow use of any non-RAP picture preceding said DRAP picture in decoding order in said video bitstream as a reference picture,
• wherein the instructions further cause the at least one processor to:
• identify data accompanying said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• decode the DRAP picture using the identified data accompanying said DRAP picture.

A non-transitory computer readable medium storing computer program comprising instructions, which when executed by at least one processor, cause said at least one processor to:

• encode an intra random access point, IRAP, picture of said video bitstream;
• encode a dependent random access point, DRAP, picture of said video bitstream using one of said IRAP picture and a preceding, according to a decoding order, DRAP picture in said video bitstream, or both, as sole reference picture(s) for decoding said DRAP picture, so that said DRAP picture together with the reference picture(s) used for decoding said DRAP picture constitute a random access point in said video bitstream for a random access operation, wherein said DRAP picture is marked as a picture for use as a reference picture by pictures following said DRAP picture in decoding order and the random access point identifying a location other than a beginning of said video bitstream where to start decoding said video bitstream, and
• encode at least one non-random access point, non-RAP, picture of said video stream following said DRAP picture in output order and decoding order, said at least one non-RAP picture is encoded to not allow use of use any non-RAP picture preceding said DRAP picture in decoding order in said video stream as reference picture,
• wherein the instructions further cause the at least one processor to:
• generate data to accompany said DRAP picture that indicates said IRAP picture and said preceding DRAP picture are required to decode said DRAP picture;
• and
• encode the DRAP picture using the generated data.