Systems and methods for protecting elementary bitstreams incorporating independently encoded tiles
Systems and methods for partial frame encryption in accordance with embodiments of the invention are disclosed. In one embodiment, the method receives a video bitstream that includes several frames, each frame including several independently encoded compression units within the frame, encrypts a portion of each of several compression units in several frames, and generates an output bitstream that includes the several independently encoded compression units including the encrypted portions of the compression units.
1. A non-transitory machine readable medium containing processor instructions, where execution of the instructions by a set of one or more processors causes the set of processors to perform a process comprising:
receiving at least a portion of a container file that contains encrypted video comprising a plurality of encoded frames of video and encryption-related metadata, where:
each of the plurality of encoded frames of video comprises a plurality of tiles that partition the encoded frame of video into rectangular regions and are independently encoded; and
the plurality of encoded frames of video comprises a partially encrypted frame of video that is encrypted using partial frame encryption such that each of the plurality of tiles within the partially encrypted frame of video includes at least one portion that is protected using encryption and at least one portion that is not encrypted;
locating encryption-related metadata from the container file, where the located encryption-related metadata identifies portions of the partially encrypted frame for decryption prior to decoding the plurality of tiles within the partially encrypted frame;
decrypting the portions of the partially encrypted frame identified by the located encryption-related metadata to obtain a decrypted frame; and
decoding the decrypted frame using information from a header associated with the frame to determine the locations of the plurality of tiles.
2. The non-transitory machine readable medium of claim 1 , wherein a tile is an independently decodable portion of a particular frame of video and does not depend upon another compression unit within the particular frame in order to be decoded.
3. The non-transitory machine readable medium of claim 1 , further comprising
parsing the header associated with the frame to identify a structure of the files within the frame.
4. The non-transitory machine readable medium of claim 1 , wherein the header associated with the frame comprises pointers, where each pointer is a pointer to a start location of one of the plurality of tiles.
5. The non-transitory machine readable medium of claim 1 , wherein the header associated with the frame comprises offsets indicating a start location of the encrypted portion of one of the plurality of tiles within the frame.
6. The non-transitory machine readable medium of claim 1 , wherein the plurality of tiles is fixed at locations within the partially encrypted frame determined using the information from the header.
7. The non-transitory machine readable medium of claim 1 , wherein the plurality of tiles is located in different locations for different partially encrypted frames.
8. The non-transitory machine readable medium of claim 1 , wherein the encryption-related metadata are contained in a separate DRM track at least a portion of which is located within the at least one portion of the container file.
9. The non-transitory machine readable medium of claim 1 , wherein decrypting the portions of the partially encrypted frame comprises decrypting each of the at least one portion that is protected using encryption within each of the plurality of tiles within the partially encrypted frame of video using an AES cipher.
10. The non-transitory machine readable medium of claim 1 , wherein the plurality of encoded frames of video form part of a video bitstream further comprising at least one unit containing a parameter set and identifies the locations of the plurality of tiles within the encoded frames of video.
11. The non-transitory machine readable medium of claim 10 , wherein parameters related to each tile in the plurality of tiles are signaled in the parameter set.
12. A playback device comprising:
a memory; and
a processor configured to communicate with the memory, where the memory contains a decoder application;
wherein the decoder application directs the processor to:
receive at least a portion of a container file that contains encrypted video comprising a plurality of encoded frames of video and encryption related metadata, where:
each of the plurality of encoded frames of video comprises a plurality of tiles that partition the encoded frame of video into rectangular regions and are independently encoded; and
the plurality of encoded frames of video comprises a partially encrypted frame of video that is encrypted using partial frame encryption such that each of the plurality of tiles within the partially encrypted frame of video includes at least one portion that is protected using encryption and at least one portion that is not encrypted;
locate encryption-related metadata from the container file, where the located encryption-related metadata identifies portions of the partially encrypted frame for decryption prior to decoding the plurality of tiles within the partially encrypted frame;
decrypt the portions of the partially encrypted frame identified by the located encryption-related metadata to obtain a decrypted frame;
decode the decrypted frame using information from a header associated with the frame to determine the locations of the plurality of tiles; and
display the decoded frame.
13. The playback device of claim 12 , wherein a tile is an independently decodable portion of a particular frame of video and does not depend upon another compression unit within the particular frame in order to be decoded.
14. The playback device of claim 12 , further comprising
parsing the header associated with the frame to identify a structure of the tiles within the frame.
15. The playback device of claim 12 , wherein the header associated with the frame comprises pointers, where each pointer is a pointer to a start location of one of the plurality of tiles.
16. The playback device of claim 12 , wherein the header associated with the frame comprises offsets indicating a start location of the encrypted portion of one of the plurality of tiles within the frame.
17. The playback device of claim 12 , wherein the plurality of tiles is fixed at certain locations within the partially encrypted frame.
18. The playback device of claim 12 , wherein the plurality of tiles is located in different locations for different partially encrypted frames.
19. The playback device of claim 12 , wherein the encryption-related metadata are contained in a separate DRM track within the at least one portion of the container file.
20. The playback device of claim 12 , wherein decrypting the portions of the partially encrypted frame comprises decrypting the encrypted portion using an AES cipher.
21. The playback device of claim 12 , wherein the plurality of encoded frames of video form part of a video bitstream further comprising at least one unit containing a parameter set and identifies the locations of the plurality of tiles within the encoded frames of video.
22. The playback device of claim 21 , wherein parameters related to each tile in the plurality of tiles are signaled in the parameter set.
23. A playback device comprising:
a memory; and
a processor configured to communicate with a memory, where the memory contains a video player application;
wherein the video player application directs the processor to:
receive at least a portion of a container file that contains encrypted is video comprising a plurality of encoded frames of video and encryption-related metadata, where:
each of the plurality of encoded frames of video comprises a plurality of tiles that partition the encoded frame of video into rectangular regions and are independently encoded; and
the plurality of encoded frames of video comprises a partially encrypted frame of video that is encrypted using partial frame encryption such that each of the plurality of tiles within the partially encrypted frame of video includes at least one portion that is protected using encryption and at least one portion that is not encrypted, where the locations of the plurality of tiles are determined using information from a header associated with the frame;
locate encryption-related metadata from the container file, where the located encryption-related metadata are contained in a separate DRM track at least a portion of which is located within the at least one portion of the container file, and identifies portions of the partially encrypted frame for decryption prior to decoding the plurality of tiles within the partially encrypted frame;
decrypt the portions of the partially encrypted frame identified by the located encryption-related metadata to obtain a decrypted frame, where decrypting the portions of the partially encrypted frame comprises decrypting each of the at least one portion that is protected using encryption within each of the plurality of tiles within the partially encrypted frame of video using an AES cipher;
decode the decrypted frame using information from the header associated with the frame; and
display the decoded frame.