Adaptive coding and streaming of multi-directional video
In communication applications, aggregate source image data at a transmitter exceeds the data that is needed to display a rendering of a viewport at a receiver. Improved streaming techniques that include estimating a location of a viewport at a future time. According to such techniques, the viewport may represent a portion of an image from a multi-directional video to be displayed at the future time, and tile(s) of the image may be identified in which the viewport is estimated to be located. In these techniques, the image data of tile(s) in which the viewport is estimated to be located may be requested at a first service tier, and the other tile in which the viewport is not estimated to be located may be requested at a second service tier, lower than the first service tier.
1. A method for streaming video data, comprising:
estimating a direction of movement of gaze location and a future location of a viewport at a future time, wherein the viewport represents a portion of an image from a multi-directional video to be displayed at the future time and the gaze location is within the viewport;
identifying a first region of the image along the estimated direction of movement of gaze location;
comparing the estimated direction of movement of gaze location to a hint of a direction of movement of gaze location from a source of the multi-directional video;
requesting image data for the first region and a second region representing content of the image based on the comparison, the second region including an identified portion of the image outside of the first region,
wherein the image data of the first region is requested at a first service tier, and the image data of the second region is requested at a second service tier, lower than the first service tier.
2. The method of claim 1 , wherein the requesting includes requesting image data for a region corresponding to a present location of the viewport at a highest service tier.
3. The method of claim 1 , wherein the estimating comprises:
comparing viewing habits of a current viewer to viewing habits of other viewers; and
predicting the future location of the viewport based on the comparison.
4. The method of claim 1 , wherein the estimating comprises:
comparing a motion of a current viewer's gaze to a dominant motion in the multi-directional video; and
predicting the future location of the viewport based on the comparison.
5. The method of claim 1 , further comprising:
identifying an object in the multi-directional video stream at a gaze location of a viewer;
identifying a motion of the object; and
deriving the future location of the viewport from the motion of the object.
6. A rendering system, comprising:
a buffer for storing tiles of multi-directional image data;
an image output for rendering a viewport of image contents on a display;
a controller for:
estimating a direction of movement of gaze location and a future location of a viewport at a future time, wherein the viewport represents a portion of an image from a multi-directional video to be displayed at the future time and the gaze location is within the viewport;
identifying a first region of the image along the estimated direction of movement of gaze location;
comparing the estimated direction of movement of gaze location to a hint of a direction of movement of gaze location from a source of the multi-directional video;
requesting image data for the first region and a second region representing content of the image based on the comparison, the second region including an identified portion of the image outside of the first region,
wherein the image data of the first region is requested at a first service tier, and the image data of the second region is requested at a second service tier, lower than the first service tier.
7. A method for streaming video data, comprising:
estimating, based on a hint of a direction of movement of gaze location from a source of a multi-directional video, a direction of movement of gaze location and a future location of a viewport at a future time, wherein the viewport represents a portion of an image from a multi-directional video to be displayed at the future time and a gaze location is within the viewport;
identifying region(s) of the image along the estimated direction of movement and a first region of the estimated future location of the viewport;
requesting image data for the first region and a second region representing content of the image, the second region including an identified portion of the image outside of the first region,
wherein the image data of the first region is requested at a first service tier, and the image data of the second region is requested at a second service tier, lower than the first service tier.
8. The method of claim 7 , wherein the requesting includes requesting image data for a region corresponding to a present location of the viewport at a highest service tier.
9. The method of claim 7 , further comprising:
comparing the estimated direction of movement to a estimate of direction of viewport movement for a current viewer of the multi-directional video; and
wherein, when the estimated direction matches the viewport hint, the estimated future location of the viewport is derived from a hint of a future gaze location from a source of the multi-directional video.
10. The method of claim 7 , wherein the estimating comprises:
comparing viewing habits of a current viewer to viewing habits of other viewers; and
predicting the future location of the viewport based on the comparison.
11. The method of claim 7 , wherein the estimating comprises:
comparing a motion of a current viewer's gaze to a dominant motion in the multi-directional video; and
predicting the future location of the viewport based on the comparison.
12. The method of claim 7 , further comprising:
identifying an object in the multi-directional video stream at a gaze location of a viewer;
identifying a motion of the object; and
deriving the future viewport location from the motion of the object.
13. A non-transitory storage medium including instructions that, when executed by a processor, cause:
estimating, based on a hint of a direction of movement of gaze location from a source of a multi-directional video, a direction of movement of gaze location and a future location of a viewport at a future time, wherein the viewport represents a portion of an image from a multi-directional video to be displayed at the future time and a gaze location is within the viewport;
identifying region(s) of the image along the estimated direction of movement and a first region of the estimated future location of the viewport;
requesting image data for the first region and a second region representing content of the image, the second region including an identified portion of the image outside of the first region,
wherein the image data of the first region is requested at a first service tier, and the image data of the second region is requested at a second service tier, lower than the first service tier.
14. The non-transitory storage medium of claim 13 , wherein the requesting includes requesting image data for a region corresponding to a present location of the viewport at a highest service tier.
15. The non-transitory storage medium of claim 13 , further comprising:
comparing the estimated direction of movement to a estimate of direction of viewport movement for a current viewer of the multi-directional video; and
wherein, when the estimated direction matches the viewport hint, the estimated future location of the viewport is derived from a hint of a future gaze location from a source of the multi-directional video.
16. The non-transitory storage medium of claim 13 , wherein the estimating comprises:
comparing viewing habits of a current viewer to viewing habits of other viewers; and
predicting the future location of the viewport based on the comparison.
17. The non-transitory storage medium of claim 13 , wherein the estimating comprises:
comparing a motion of a current viewer's gaze to a dominant motion in the multi-directional video; and
predicting the future location of the viewport based on the comparison.
18. The non-transitory storage medium of claim 13 , further comprising:
identifying an object in the multi-directional video stream at a gaze location of a viewer;
identifying a motion of the object; and
deriving the future viewport location from the motion of the object.
19. The method of claim 1 , wherein the first service tier and the second service tier are determined based on the comparison.