Method, an apparatus and a computer program product for video conferencing
A method comprising obtaining a 360-degree video content from a video source; projecting the 360-degree video content onto a 2D image plane; dividing the projected 360-degree video content into a plurality of regions, wherein the regions are partly overlapping and each region covers a region of the 360-degree video content suitable for a viewport presentation; receiving a request for a viewport orientation of the 360-degree video content from a client; and providing the client with an viewport presentation of the region corresponding to the requested viewport orientation.
1. An apparatus comprising:
at least one processor; and
at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to:
obtain a 360-degree video content from a video source;
project the 360-degree video content onto a two-dimensional image plane;
divide the projected 360-degree video content into a plurality of regions, wherein the plurality of regions are at least partly overlapping, wherein a region of the plurality of regions enables at least one viewport presentation of the projected 360-degree video content;
receive a request for a viewport orientation of the 360-degree video content from a client;
provide, to the client, a viewport presentation of a region, of the plurality of regions, corresponding to the requested viewport orientation; and
provide, to the client, a viewport presentation of a fallback region in response to the client switching between regions while a time to a next keyframe is greater than a threshold, wherein the fallback region comprises a region encoded with at least one of:
a quality lower than a quality associated with, at least, the plurality of regions,
a frame rate lower than a frame rate associated with, at least, the plurality of regions,
a resolution lower than a resolution associated with, at least, the plurality of regions,
no dependent frames, or
a period for reference pictures that is shorter than a period for reference pictures associated with, at least, the plurality of regions.
2. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
carry out session negotiations with a plurality of client devices for a viewport-dependent delivery of the 360-degree video content; and
determine, based on at least one of the plurality of client devices or parameters of the session negotiations, regions of the plurality of regions to be encoded with a same resolution.
3. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
obtain information from a plurality of client devices about motion patterns; and
adjust the division of the projected 360-degree video content into the plurality of regions according to said information so as to minimize a need for region change.
4. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
encode respective regions of the plurality of regions with at least one of:
a same encoding bitrate,
a same encoding quality,
a different encoding bitrate, or
a different encoding quality.
5. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
determine that at least two regions correspond to the viewport orientation requested by the client, wherein the requested viewport orientation corresponds to an overlap between the at least two regions.
6. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
divide the projected 360-degree video content into a plurality of sets of regions, wherein regions in at least a first set of the plurality of regions have a larger field-of-view and regions in at least a second set of the plurality of regions have a smaller field-of-view.
7. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
encode regions corresponding to viewport orientations requested by client devices.
8. The apparatus according to claim 1 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
determine two polar regions for the 360-degree video content.
9. The apparatus according to claim 7 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to at least one of:
insert key frames, at a first periodicity, into the viewport presentation of the encoded region provided to the client; or
insert the key frames, at a second periodicity, into the viewport presentation of the encoded region provided to the client in response to, at least, a frequency of switching between regions by the client, wherein the second periodicity is higher than the first periodicity.
10. The apparatus according to claim 1 , wherein a number of the plurality of regions and their degree of overlap is fixed, and wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to:
redefine the plurality of regions as a sliding field-of-view such that respective regions of the plurality of regions are slid an equal amount in a same direction when the plurality of regions are redefined.
11. The apparatus according to claim 1 , wherein a number of the plurality of regions and their degree of overlap is changeable.
12. The apparatus according to claim 11 , wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to one of:
redefine the plurality of regions as a sliding field-of-view such that sliding of one region does not directly influence sliding of another region; or
redefine the plurality of regions as a sliding field-of-view such that sliding of one region influences sliding of at least one other region with a different degree of overlap.
13. A method, comprising:
obtaining a 360-degree video content from a video source;
projecting the 360-degree video content onto a two-dimensional image plane;
dividing the projected 360-degree video content into a plurality of regions, wherein the plurality of regions are at least partly overlapping, wherein a region of the plurality of regions enables at least one viewport presentation of the projected 360-degree video content;
receiving a request for a viewport orientation of the 360-degree video content from a client;
providing, to the client, a viewport presentation of a region, of the plurality of regions, corresponding to the requested viewport orientation; and
providing, to the client, a viewport presentation of a fallback region in response to the client switching between regions while a time to a next keyframe is greater than a threshold, wherein the fallback region comprises a region encoded with at least one of:
a quality lower than a quality associated with, at least, the plurality of regions,
a frame rate lower than a frame rate associated with, at least, the plurality of regions,
a resolution lower than a resolution associated with, at least, the plurality of regions,
no dependent frames, or
a period for reference pictures that is shorter than a period for reference pictures associated with, at least, the plurality of regions.
14. The method according to claim 13 , further comprising:
carrying out session negotiations with a plurality of client devices for a viewport-dependent delivery of the 360-degree video content; and
determining, based on at least one of the plurality of client devices or parameters of the session negotiations, regions of the plurality of regions to be encoded with a same resolution.
15. The method according to claim 13 , further comprising:
obtaining information from a plurality of client devices about motion patterns; and
adjusting the division of the projected 360-degree video content into the plurality of regions according to said information so as to minimize a need for region change.
16. The method according to claim 13 , further comprising:
encoding respective regions of the plurality of regions with at least one of:
a same encoding bitrate,
a same encoding quality,
a different encoding bitrate, or
a different encoding quality.
17. The method according to claim 13 , further comprising:
determining that at least two regions correspond to the viewport orientation requested by the client, wherein the requested viewport orientation corresponds to an overlap between the at least two regions.
18. The method according to claim 13 , further comprising:
dividing the projected 360-degree video content into a plurality of sets of regions, wherein regions in at least a first set of the plurality of regions have a larger field-of-view and regions in at least a second set of the plurality of regions have a smaller field-of-view.
19. The method according to claim 13 , further comprising:
encoding regions corresponding to viewport orientations requested by client devices.
20. The method according to claim 13 , further comprising:
determining two polar regions for the 360-degree video content.
21. A non-transitory computer-readable medium comprising program instructions stored thereon for performing at least the following:
causing obtaining of a 360-degree video content from a video source;
projecting the 360-degree video content onto a two-dimensional image plane;
dividing the projected 360-degree video content into a plurality of regions, wherein the plurality of regions are at least partly overlapping, wherein a region of the plurality of regions enables at least one viewport presentation of the projected 360-degree video content;
causing receiving of a request for a viewport orientation of the 360-degree video content from a client; and
causing providing, to the client, of a viewport presentation of a region, of the plurality of regions, corresponding to the requested viewport orientation; and
causing providing, to the client, of a viewport presentation of a fallback region in response to the client switching between regions while a time to a next keyframe is greater than a threshold, wherein the fallback region comprises a region encoded with at least one of:
a quality lower than a quality associated with, at least, the plurality of regions,
a frame rate lower than a frame rate associated with, at least, the plurality of regions,
a resolution lower than a resolution associated with, at least, the plurality of regions,
no dependent frames, or
a period for reference pictures that is shorter than a period for reference pictures associated with, at least, the plurality of regions.