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 an encoded video bitstream comprising a plurality of frames, each frame comprising a plurality of independently encoded compression units within the frame, wherein each independently encoded compression unit is a tile;
for each frame of the plurality of frames:
receiving a metadata header identifying the locations of the plurality of independently encoded compression units within the frame;
receiving encryption information identifying locations of encrypted portions of the plurality of independently encoded compression units in the frame;
decrypting the encrypted portions of each of a plurality of compression units in the frame based on the received metadata header and the received encryption information; and
upon decrypting the encrypted portions of the plurality of compression units of the frame, decoding, by a plurality of processors in parallel, the frame with the decrypted plurality of compression units.
2. The non-transitory machine readable medium of claim 1 , wherein a compression unit is an independently decodable portion of a particular frame of video such that it 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 , wherein decrypting the portion of each of the plurality of compression units comprises determining that compression units are in a state of being enabled based on information within a header associated with the video bitstream.
4. The non-transitory machine readable medium of claim 1 , wherein each portion of the encrypted portions is selected from the group consisting of i) a first N bytes of the compression unit, ii) a last N bytes of the compression unit, iii) a middle portion of N bytes within the compression unit and iv) a pattern of N bytes within the compression unit.
5. The non-transitory machine readable medium of claim 1 , wherein the compression units are tiles within a High-Efficiency Video Coding (HEVC) standard and the video bitstream is encoded based on the HEVC standard.
6. The non-transitory machine readable medium of claim 5 , wherein the metadata header includes a Picture Parameter Set (PPS) of the HEVC video bitstream to identify a structure of the tiles within the video bitstream.
7. The non-transitory machine readable medium of claim 1 , wherein decrypting the encrypted portions of each of the plurality of compression units comprises using a common encryption format (CENC) to decrypt the portions.
8. A content decoder comprising:
a memory;
a processor configured to communicate with the memory, where the memory contains instructions;
wherein execution of the instructions by the processor causes the processor to:
receive an encoded video bitstream comprising a plurality of frames, each frame comprising a plurality of independently encoded compression units within the frame, wherein each independently encoded compression unit is a tile;
for each frame of the plurality of frames:
receiving a metadata header identifying the locations of the plurality of independently encoded compression units within the frame;
receive encryption information identifying locations of encrypted portions of the plurality of independently encoded compression units in the frame;
decrypt the encrypted portions of each of a plurality of compression units in the frame based on the received metadata header and the received encryption information; and
upon decrypting the encrypted portions of the plurality of compression units of the frame, decode, by a plurality of processors in parallel, the frame with the decrypted plurality of compression units.
9. The content decoder claim 8 , wherein a compression unit is an independently decodable portion of a particular frame of video such that it does not depend upon another compression unit within the particular frame in order to be decoded.
10. The content decoder of claim 8 , wherein decrypting the portion of each of the plurality of compression units comprises determining that compression units are in a state of being enabled based on information within a header associated with the video bitstream.
11. The content decoder of claim 8 , wherein the portion is selected from the group consisting of i) a first N bytes of the compression unit, ii) a last N bytes of the compression unit, iii) a middle portion of N bytes within the compression unit and iv) a pattern of N bytes within the compression unit.
12. The content decoder of claim 8 , wherein the compression units are tiles within a High-Efficiency Video Coding (HEVC) standard and the video bitstream is decoded based on the HEVC standard.
13. The content decoder claim 12 , wherein the metadata header includes a Picture Parameter Set (PPS) of the HEVC video bitstream to identify a structure of the tiles within the video bitstream.
14. The content decoder claim 8 , wherein decrypting the encrypted portions of each of the plurality of compression units comprises using a common encryption format (CENC) to decrypt the portions.