1. A method of decoding video data, the method comprising:', 'decoding, from an encoded video bitstream, a video parameter set (VPS) that includes a plurality of hypothetical reference decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax stmcture in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax stmcture include a common set of HRD parameters, wherein the common set of HRD parameters is common to ail sub-layers of the encoded video bitstream; and', 'performing an operation using the HRD parameters of at least one of the HRD parameter syntax structures.

2. The method of claim 2, further comprising:', 'determining that a particular HRD parameter syntax structure does not include a common set of HRD parameters, and', 'wherein performing the operation using the HRD parameters of at least one of the HRD parameter syntax structures comprises performing the operation using a common set of HRD parameters associated with a previous HRD parameter syntax stmcture and additional HRD parameters of the particular HRD parameter syntax structure.

3. The method of claim 1, wherein the first HRD parameter syntax stmcture signaled in the VPS includes a first common set of HRD parameters.

4. The method of claim 3, wherein a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters.

5. The method of claim 3, wherein at least one HRD parameter syntax structure signaled in the VPS does not include a common set of HR D parameters.

6. The method of claim 1, wherein each of the HRD parameter syntax structures is applicable to an operation point of the encoded video bitstream.

7. The method of claim 1 , wherein at least one of the HRD parameter syntax structures is applicable to multiple operation points of the encoded video bitstream.

8. A video decoding device comprising one or more processors configured to: decode, from an encoded video bitstream, a video parameter set (VPS) that includes a plurality of hypothetical reference decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax structure in the pluraiity of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters, wherein the common set of HRD parameters is common to ail sub-layers of the encoded video bitstream; and', 'perform an operation using the HRD parameters of at least one of the HRD parameter syntax structures.

9. The video decoding device of claim 8, wherein the one or more processors are further configured to:', 'determine that a particular HRD parameter syntax structure does not include a common set of HRD parameters, and', 'perform the operation using a common set of HRD parameters associated with a previous HRD parameter syntax structure and additional HRD parameters of the particular HRD parameter syntax structure

10. The video decoding device of claim 8, wherein the first HRD parameter syntax structure signaled in the VPS includes a first common set of HRD parameters.1. The video decoding device of claim 10, wherein a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters

12. The video decoding device of claim 10, wherein at least one HRD parameter syntax structure signaled in the VPS does not include a common set of HRD parameters

13. The video decoding device of claim 8, wherein each of the HRD parameter syntax structures is applicable to an operation point of the encoded video bitstrcam,14. The video decoding device of claim 8, wherein at least one of the HRD parameter syntax structures is applicable to multiple operation points of the encoded video bitstream

15. A video decoding device comprising:', 'means for decoding, from an encoded video bitstream, a video parameter set (VPS) that includes a plurality of hypothetical reference decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax structure in the plurality of HRD parameter syntax stiuctures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters, wherein the common set of HRD parameters is common to all sub-layers of the encoded video bitstream; and', 'means for performing an operation using the HRD parameters of at least one of the HRD parameter syntax structures

16. The video decoding device of claim 15 , wherein:', 'the first HRD parameter syntax structure signaled in the VPS includes a first common set of HRD parameters,', 'a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters, and', 'each of the HRD parameter syntax structures is applicable to an operation point of the encoded video bitstream

17. A computer-readable storage medium that stores instructions that, when executed by a video decoding device, configure the video decoding device to:', 'decode, from an encoded video bitstream, a video parameter set (VPS) that includes a plurality of hypothetical reference decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax stracture in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters, wherein the common set of HRD parameters is common to all sub-layers of the encoded video bitstream; and', 'perform an operation using the HRD parameters of at least one of the HRD parameter syntax structures

18. The computer-readable storage medium of claim 17, wherein:', 'the first HRD parameter syntax structure signaled in the VPS includes a first common set of HRD parameters,', 'a subsequent HRD parameter syntax stracture signaled in the VPS includes a second, different common set of HRD parameters, and', 'each of the HRD parameter syntax structures is applicable to an operation point of the encoded video bitstream

19. A method of encoding video data, the method comprising:', 'generating a video parameter set (VPS) that includes a plurality of Hypothetical Reference Decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax structure in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters in addition to a set of sub- layer- specific HRD parameter information specific to a particular sub-layer of an encoded video bitstream, wherein the common set of HRD parameters is common to all sublayers of the encoded video bitstream; and', 'signaling the VPS in the encoded video bitstream.

20. The method of claim 19, wherein the first HRD parameter syntax s tructure signaled in the VPS includes a first common set of HRD parameters.

21. The method of claim 20, wherein a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters.

22. The method of claim 20, wherein at least one HRD parameter syntax structure signaled in the VPS does not include a common set of HRD parameters.

23. A video encoding device comprising one or more processors configured to: generate a video parameter set (VPS) that includes a plurality of Hypothetical', 'Reference Decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax structure in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax stiucture include a common set of HRD parameters in addition to a set of sub-layer- specific HRD parameter information specific to a particular sub-layer of an encoded video bitstream, wherein the common set of HRD parameters is common to ail sublayers of the encoded video bitstream; and', 'signal the VPS in the encoded video bitstream.

24. The video encoding device of claim 23, wherein the first HRD parameter syntax stiucture signaled in the VPS includes a first common set of HRD parameters.

25. The video encoding device of claim 24, wherein a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters.

26. The video encoding device of claim 24, wherein at least one HRD parameter syn tax s tructure signaled in the VPS does not include a common set of HRD parameters.

27. A video encoding device comprising:', 'means for generating, a video parameter set (VPS) that includes a plurality of Hypothetical Reference Decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax structure in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters in addition to a set of sub- layer- specific HRD parameter information specific to a particular sub-layer of an encoded video bitstream, wherein the common set of HRD parameters is common to all sublayers of the encoded video bitstream; and', 'means for signaling the VPS in the encoded video bitstream.

28. The video encoding device of claim 27, wherein:', 'the first HRD parameter syntax structure signaled in the VPS includes a first common set of HRD parameters,', 'a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters, and', 'each of the HRD parameter syntax structures is applicable to an operation point of the encoded video bitstream.

29. A computer-readable storage medium that stores instructions that, when executed by a video encoding device, configure the video encoding device to:', 'generate a video parameter set (V PS) that includes a plurality of Hypothetical Reference Decoder (HRD) parameter syntax structures that each include HRD parameters, wherein for each respective HRD parameter syntax structure in the plurality of HRD parameter syntax structures, the VPS further includes a syntax element indicating whether the HRD parameters of the respective HRD parameter syntax structure include a common set of HRD parameters in addition to a set of sub- layer- specific HRD parameter information specific to a particular sub-layer of the encoded video bitstream, wherein the common set of HRD parameters is common to all sublayers of the encoded video bitstream; and', 'signal the VPS in the encoded video bitstream.

30. The computer-readable storage medium of claim 29, wherein:', 'the first HRD parameter syntax stiucture signaled in the VPS includes a first common set of HRD parameters,', 'a subsequent HRD parameter syntax structure signaled in the VPS includes a second, different common set of HRD parameters, and', 'each of the HRD parameter syntax structures is applicable to an operation point of the encoded video bitstream.']