Systems and methods for spatially selective video coding
Systems and methods for providing panoramic image and/or video content using spatially selective encoding and/or decoding. Panoramic content may include stitched spherical (360-degree) images and/or VR video. In some implementations, selective encoding functionality may be embodied in a spherical image capture device that may include two lenses configured to capture pairs of hemispherical images. Encoded source images may be decoded and stitched in order to obtain a combined image characterized by a greater field of view as compared to source images. The stitched image may be encoded using a selective encoding methodology including: partitioning a stitched image into multiple portions, determining if a portion is to be re-encoded. If the image portion is to be re-encoded, re-encoding the image portion. If an image portion is not to be re-encoded, copying previously encoded image portion in lieu of encoding.
1. A computer readable apparatus comprising a storage medium having a plurality of computer executable instructions stored thereon, the plurality of computer executable instructions being configured to, when executed by a processor apparatus, cause a computerized apparatus to:
access a stitched panoramic image having been encoded at a first quality distribution;
determine individual portions of the stitched panoramic image, the determination comprising a determination of a partitioning configuration for the stitched panoramic image, the partitioning configuration comprising: (i) a circular center area portion, and (ii) a surrounding area portion that is proximate the circular center area portion;
encode a first portion of the individual portions of the stitched panoramic image using a second quality distribution;
combine the encoded first portion of the individual portions of the stitched panoramic image with other portions of the individual portions of the stitched panoramic image to produce a combined panoramic portion of the image; and
store the combined panoramic portion of the image.
2. The computer readable apparatus of claim 1 , the plurality of computer executable instructions being further configured to, when executed by the processor apparatus, cause the computerized apparatus to:
provide the stored combined panoramic portion of the image to a display device.
3. The computer readable apparatus of claim 1 , wherein the first portion of the individual portions of the stitched panoramic image comprises the surrounding area portion.
4. The computer readable apparatus of claim 1 , wherein the circular center area portion is encoded at the first quality distribution.
5. The computer readable apparatus of claim 1 , wherein the other portions of the individual portions of the stitched panoramic image are retrieved from the stitched panoramic image that has been encoded at the first quality distribution.
6. The computer readable apparatus of claim 2 , wherein:
the display device comprises a virtual reality display device; and
the plurality of computer executable instructions are further configured to, when executed by the processor apparatus, cause the computerized apparatus: determine a viewport change of the virtual reality display device.
7. The computer readable apparatus of claim 1 , wherein the stitched panoramic image comprises a spherical image derived from a plurality of at least hemispherical source images.
8. A method for selectively encoding an image, the method comprising:
accessing a centrally located portion of a stitched version of the image, the centrally located portion residing away from a stitching line of the stitched version of the image;
evaluating whether portions of the stitched version of the image are to be encoded;
for a first portion of the portions of the stitched version of the image that are not to be encoded, accessing a previously available encoded image portion;
for a second portion of the portions of the stitched version of the image that are to be encoded, encoding the second portion; and
obtaining an encoded stitched image by combining the previously available encoded image portion and the encoded second portion.
9. The method of claim 8 , wherein the encoding of the second portion comprises encoding a peripherally located portion of the stitched version of the image, the peripherally located portion comprising the stitching line of the stitched version of the image.
10. The method of claim 8 , further comprising stitching two or more fisheye projections in order to provide the stitched version of the image.
11. The method of claim 8 , further comprising determining the first portion of the portions of the stitched version of the image and determining the second portion of the portions of the stitched version of the image, the determining utilizing an image map for the stitched version of the image.
12. The method of claim 9 , wherein the encoding of the peripherally located portion of the stitched version of the image comprises encoding the peripherally located portion of the stitched version of the image as a motion-constrained tile of an encoder.
13. The method of claim 8 , wherein:
the centrally located portion comprises a circular shape; and
the encoding of the second portion comprises encoding one or more peripheral portions, the one or more peripheral portions comprising the stitching line of the stitched version of the image.
14. The method of claim 8 , wherein the centrally located portion comprises polygonal shape.
15. A system for selectively encoding an image, the system comprising:
an electronic storage configured to store a stitched version of the image;
a communications interface configured to communicate a bit stream to a client device; and
a processor apparatus configured to execute a plurality of computer readable instructions, the plurality of computer readable instructions configured to, when executed by the processor apparatus:
access the stitched version of the image;
evaluate whether portions of the stitched version of the image are to be encoded;
for a first portion of the portions of the stitched version of the image that are not to be encoded, access a previously available encoded image portion, the previously available encoded image portion comprising a polygon shaped central portion, the polygon shaped central portion not contiguous with a stitching line of the stitched version of the image;
for a second portion of the portions of the stitched version of the image that are to be encoded, encode the second portion; and
obtain an encoded stitched image by combination of the polygon shaped central portion and the encoded second portion.
16. The system of claim 15 , wherein the encode of the second portion comprises an encode of one or more peripheral portions that are polygon shaped, the one or more peripheral portions comprising the stitching line of the stitched version of the image.
17. The system of claim 16 , wherein the polygon shaped central portion comprises a square and the one or more peripheral portions comprise rectangles.
18. The system of claim 15 , wherein the encode of the second portion is encoded using a HEVC (High Efficiency Video Coding) standard encoder configured to partition the encoded second portion into multiple tiles; and
an encode of individual ones of the multiple tiles is configured in accordance with a motion constrained tile encoding profile.
19. The system of claim 15 , further comprising a plurality of image capturing devices, each of the plurality of image capturing devices being configured to capture at least hemispherical images, the at least hemispherical images being associated with a field of view of at least 180 degrees.
20. The system of claim 15 , further comprising a display device configured to render virtual-reality (VR) content in a 360-degree field of view, the VR content comprising the obtained encoded stitched image.