Video optimization system and method based on gaze vector information
A system and method for providing immersive video based on gaze vector information. A gaze vector is obtained from a client device operating to display an immersive video asset to a user, wherein each video frame comprises an array of tiles projected on a 3-dimensional (3D) display environment viewed by the user in which the user is immersed, the gaze vector defining a gaze direction in the 3D display environment where the user is viewing (i.e., a viewport) at any particular time. Angular separations between the viewport and remaining portions of the video frame are used in selecting different video qualities of the immersive video asset such that the viewport comprises a higher video quality than the remaining portions when displayed by the client device.
1. A client device configured to display a video asset to a user, the client device comprising:
at least one microprocessor;
a display; and
a non-transitory computer-readable storage medium coupled to the at least one microprocessor and including computer-readable instructions, when executed by the at least one processor, configured for:
effectuating receipt of a plurality of bitrate representations of the video asset, each bitrate representation having a corresponding video quality and encoded into a plurality of phase-encoded bitstreams, wherein each phase-encoded bitstream that belongs to a particular bitrate representation comprises a number (N) of frames with a specific Group-of-Pictures (GOP) structure having a GOP size (p), wherein the number of the plurality of phase-encoded bitstreams equals the GOP size and, for each p th phase-encoded bitstream, N frames are encoded as follows:
at least a first frame is encoded as an intra-coded (I) frame; and
a frame at a frame position i, for 2≤i≤N, that satisfies {i Mod (GOP size)}=p is encoded as an X-frame that has a slice header of a predictive-coded (P) frame and comprises blocks of only intra-coded data (I-blocks), otherwise, that frame is encoded as a P-frame having blocks of at least one of predictive-coded data (P-blocks) and intra-coded data (I-blocks) with a P-slice header;
responsive to gaze vector information associated with the user, generating a video frame having regions of variable video quality combined from different bitrate representations that are each encoded into [p] phase-encoded bitstreams; and
rendering the video frame for presentation via the display, wherein a first region of the video frame corresponding to a viewport has a first video quality and at least a second region of the video frame outside of the viewport has a second video quality lower than the first video quality.
2. A client device configured to display a video asset to a user, the client device comprising:
at least one microprocessor;
a display; and
a non-transitory computer-readable storage medium coupled to the at least one microprocessor and including computer-readable instructions, when executed by the at least one processor, configured for:
effectuating receipt of a plurality of bitrate representations of the video asset, each bitrate representation having a corresponding video quality and encoded into a first coded bitstream comprising a plurality of frames with a specific Group-of-Pictures (GOP) structure, wherein each GOP starts with an intra-coded (I) frame followed by a set of frames including at least one predictive-coded (P) frame, and into a second coded bitstream comprising a plurality of frames with a GOP structure that has a size coextensive with a size of the GOP structure of the first coded bitstream, wherein each GOP of the second coded bitstream starts with an I-frame followed by a plurality of X-frames, each X-frame having a slice header of a P-frame and comprising blocks of only intra-coded data (I-blocks);
responsive to gaze vector information associated with the user, generating a video frame having regions of variable video quality combined from different bitrate representations that are each encoded into the first and second coded bitstreams; and
rendering the video frame for presentation via the display, wherein a first region of the video frame corresponding to a viewport has a first video quality and at least a second region of the video frame outside of the viewport has a second video quality lower than the first video quality.