Apparatus, a method and a computer program for video coding and decoding
Four or more bitstream versions of a same content are encoded and divided into segments of independently coded tile sets representing multiple spatial regions. First and second bitstreams include independently coded tile sets encoded at a first quality. Third and fourth bitstreams include independently coded tile sets encoded at a second quality. First and third bitstreams have first random access picture interval. Second and fourth bitstreams have second random access picture interval. Independently coded tile sets are grouped into multiple groups of collocated sub-picture tracks, only one of said tile sets per group is intended to be received and/or decoded per any segment. Instruction(s) are generated for merging tile sets of different spatial locations into coded picture(s), causing a tile set originating from a random access picture to be decoded as a tile set originating from a non-random-access picture when merged with a tile set originating from a non-random-access picture.
1. A method comprising:
encoding or obtaining at least two bitstream versions of a same video content, wherein the same video content is divided into image segments, wherein each of the at least two bitstream version of the same video content is encoded at different quality, wherein a first bitstream comprises a random access picture at a first time instance and a second bitstream comprises a non-random access picture at said first time instance;
providing an image segment of the first bitstream comprising said random access picture with a video coding layer network abstraction layer (VCL NAL) unit type indicative of a random access image segment;
providing an image segment of the second bitstream comprising said non-random access picture with a VCL NAL unit type indicative of a non-random access image segment; and
generating at least one instruction for merging said at least two bitstreams, wherein said image segments from the first and the second bitstreams at said first time instance are merged into at least one coded picture.
2. The method according to claim 1 , comprising providing said at least one coded picture with a picture-level indication to indicate a picture type.
3. The method according to claim 1 , wherein generating the at least one instruction for merging comprises an instruction for rewriting a picture-level indication to indicate a non-random-access picture.
4. An apparatus comprising at least one processor, and at least one memory storing computer program code that, when executed by the processor, cause the apparatus to perform:
encoding or obtaining at least two bitstream versions of a same video content wherein the same video content is divided into image segments, wherein each of the at least two bitstream version of the same video content is encoded at different quality, wherein a first bitstream comprises a random access picture at a first time instance and a second bitstream comprises a non-random access picture at said first time instance;
providing an image segment of the first bitstream comprising said random access picture with a video coding layer network abstraction layer (VCL NAL) unit type indicative of a random access image segment;
providing an image segment of the second bitstream comprising said non-random access picture with a VCL NAL unit type indicative of a non-random access image segment; and
generating at least one instruction for merging said at least two bitstreams, wherein said image segments from the first and the second bitstreams at said first time instance are merged into at least one coded picture.
5. The apparatus according to claim 4 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform: providing said at least one coded picture with a picture-level indication to indicate a picture type.
6. The apparatus according to claim 4 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform: generating the at least one instruction for merging further comprises generating an instruction for rewriting a picture-level indication to indicate a non-random-access picture.
7. The apparatus according to claim 5 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform: encoding said picture-level indication in a picture header, a header parameter set, and/or a picture parameter set.
8. The apparatus according to claim 6 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform: encoding said picture-level indication in a picture header, a header parameter set, and/or a picture parameter set.
9. The apparatus according to claim 4 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform:
encapsulating the at least one instruction into a collector track, wherein the collector track extracts implicitly or explicitly coded video data from video tracks, and wherein the video tracks comprise coded video data of the first and second bitstreams.
10. A method comprising:
obtaining an image segment of a first bitstream with a video coding layer network abstraction layer (VCL NAL) unit type indicative of a random access image segment at a first time instance;
obtaining an image segment of a second bitstream with a VCL NAL unit type indicative of a non-random access image segment at said first time instance; and
merging said at least the first and second bitstreams, wherein image segments from the first and second bitstreams at said first time instance are merged into at least one coded picture and a picture-level indication to indicate a picture type is provided with said at least one coded picture.
11. The method according to claim 10 , wherein the merging further comprises rewriting the picture-level indication to indicate a non-random access picture.
12. The method according to claim 10 , further comprising encoding said picture-level indication in one or more of the following: a picture header, a header parameter set, or a picture parameter set.
13. The method according to claim 10 , wherein at least one VCL NAL unit type of the image segments in said at least one coded picture is allowed to differ from the picture type of said at least one coded picture.
14. An apparatus comprising at least one processor, and at least one memory storing computer program code that, when executed by the processor, cause the apparatus to perform:
obtaining an image segment of a first bitstream with a video coding layer network abstraction layer (VCL NAL) unit type indicative of a random access image segment at a first time instance;
obtaining an image segment of a second bitstream with a VCL NAL unit type indicative of a non-random access image segment at said first time instance; and
merging said at least the first and second bitstreams, wherein image segments from the first and second bitstreams at said first time instance are merged into at least one coded picture and a picture-level indication to indicate a picture type is provided with said at least one coded picture.
15. The apparatus according to claim 14 , wherein the merging further comprises rewriting the picture-level indication to indicate a non-random access picture.
16. The apparatus according to claim 15 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform:
encoding said picture-level indication in a picture header, a header parameter set, and/or a picture parameter set.
17. The apparatus according to claim 14 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform:
encoding said picture-level indication in a picture header, a header parameter set, and/or a picture parameter set.
18. The apparatus according to claim 14 , wherein at least one VCL NAL unit type of the image segments in said at least one coded picture is allowed to differ from the picture type of said at least one coded picture.
19. The apparatus according to claim 14 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform:
obtaining or inferring at least one instruction for merging said image segments into the at least one coded picture; and
processing the at least one instruction to form the at least one coded picture.
20. The apparatus according to claim 19 , wherein the at least one memory further stores computer program code that, when executed by the processor, cause the apparatus to perform: obtaining or inferring the at least one instruction from a collector track, wherein the collector track extracts implicitly or explicitly coded video data from video tracks, and wherein the video tracks comprise coded video data of the first and second bitstreams.