1. A method of decoding video data, the method comprising:', 'determining, for a supplemental enhancement information (SEI) network abstraction layer (NAL) unit of a bitstream, whether a NAL unit type value for the SEI NAL unit indicates that the NAL unit comprises a prefix SEI NAL unit including a prefix SEI message or a suffix SEI NAL unit including a suffix SEI message; and', 'decoding video data of the bitstream following the SEI NAL unit based on whether the SEI NAL unit is the prefix SEI NAL unit or the suffix SEI NAL unit and data of the SEI NAL unit.

2. The method of claim 1, further comprising, when the SEI NAL unit comprises the suffix SEI NAL unit, extracting the suffix SEI NAL unit from an access unit (AU) that includes at least a first video coding layer (VCL) NAL unit in the AU prior to the suffix SEI NAL unit in decoding order.

3. The method of claim 2, wherein the suffix SEI NAL unit follows all VCL NAL units in the AU in decoding order.

4. A device for decoding video data, the device comprising a processor configured to determine, for a supplemental enhancement information (SEI) network abstraction layer (NAL) unit of a bitstream, whether a NAL unit type value for the SEI NAL unit indicates that the NAL unit comprises a prefix SEI NAL unit including a prefix SEI message or a suffix SEI NAL unit including a suffix SEI message, and decode video data of the bitstream following the SEI NAL unit based on whether the SEI NAL unit is the prefix SEI NAL unit or the suffix SEI NAL unit and data of the SEI NAL unit.

5. The device of claim 4, wherein the processor is configured to, when the SEI NAL unit comprises the suffix SEI NAL unit, extract the suffix SEI NAL unit from an access unit (AU) that includes at least a first video coding layer (VCL) NAL unit in the AU prior to the suffix SEI NAL unit in decoding order.

6. The device of claim 5, wherein the suffix SEI NAL unit follows all VCL NAL units in the AU in decoding order.

7. A device for decoding video data, the device comprising:', 'means for determining, for a supplemental enhancement information (SEl) network abstraction layer (NAL) unit of a bitstream, whether a NAL unit type value for the SEl NAL unit indicates that the NAL unit comprises a prefix SEl NAL unit including a prefix SEl message or a suffix SEl NAL unit including a suffix SEl message; and', 'means for decoding video data of the bitstream following the SEl NAL unit based on whether the SEl NAL unit is the prefix SEl NAL unit or the suffix SEl NAL unit and data of the SEl NAL unit.

8. The device of claim 7, further comprising means for extracting, when the SEl NAL unit comprises the suffix SEl NAL unit, the suffix SEl NAL unit from an access unit (AU) that includes at least a first video coding layer (VCL) NAL unit in the AU prior to the suffix SEl NAL unit in decoding order.

9. The device of claim 8, wherein the suffix SEl NAL unit follows all VCL NAL units in the AU in decoding order

10. A computer-readable storage medium having stored thereon instructions that, when executed, cause a processor to:', 'determine, for a supplemental enhancement information (SEl) network abstraction layer (NAL) unit of a bitstream, whether a NAL unit type value for the SEl NAL unit indicates that the NAL unit comprises a prefix SEl NAL unit including a prefix SEl message or a suffix SEl NAL unit including a suffix SEl message; and', 'decode video data of the bitstream following the SEl NAL unit based on whether the SEl NAL unit is the prefix SEl NAL unit or the suffix SEl NAL unit and data of the SEl NAL unit

11. The computer-readable storage medium of claim 10, further comprising instructions that cause the processor to, when the SEl NAL unit comprises the suffix SEl NAL unit, extract the suffix SEl NAL unit from an access unit (AU) that includes at least a first video coding layer (VCL) NAL unit in the AU prior to the suffix SEl NAL unit in decoding order

12. The computer-readable storage medium of claim 11, wherein the suffix SEl NAL unit follows all VCL NAL units in the AU in decoding order

13. A method of generating a bitstream including video data, the method comprising:', 'determining whether a supplemental enhancement information (SEl) message is a prefix SEl message or a suffix SEl message, wherein the SEl message includes data related to encoded video data;', 'encapsulating the SEl message in an SEl NAL unit, wherein the SEl NAL unit includes a NAL unit type value that indicates whether the SEl NAL unit is a prefix SEl NAL unit or a suffix SEl NAL unit and whether the SEl message is a prefix SEl message or a suffix SEl message; and', 'generating a bitstream including at least the SEl NAL unit

14. The method of claim 13, wherein generating the encoded bitstream comprises encapsulating the SEl NAL unit in an access unit (AU) such that the SEl NAL unit follows a first video coding layer (VCL) NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEl NAL unit is a suffix SEl NAL unit

15. The method of claim 14, wherein generating the bitstream further comprises encapsulating the SEl NAL unit in the AU such that the SEl NAL unit further succeeds a last VCL NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEl NAL unit is the suffix SEl NAL unit

16. A device for generating a bitstream including video data, the device comprising a processor configured to determine whether a supplemental enhancement information (SEl) message is a prefix SEl message or a suffix SEl message, wherein the SEl message includes data related to encoded video data, encapsulate the SEl message in an SEl NAL unit, wherein the SEl NAL unit includes a NAL unit type value that indicates whether the SEl NAL unit is a prefix SEl NAL unit or a suffix SEl NAL unit and whether the SEl message is a prefix SEl message or a suffix SEl message, and generate a bitstream including at least the SEl NAL unit

17. The device of claim 16, wherein the processor is configured to encapsulate the SEl NAL unit in an access unit (AU) such that the SEl NAL unit follows a first video coding layer (VCL) NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEl NAL unit is a suffix SEl NAL unit

18. The device of claim 17, wherein the processor is configured to encapsulate the SEI NAL unit in the AU such that the SEI NAL unit further succeeds a last VCL NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEI NAL unit is the suffix SEI NAL unit

19. A device for generating a bitstream including video data, the device comprising: means for determining whether a supplemental enhancement information (SEI) message is a prefix SEI message or a suffix SEI message, wherein the SEI message includes data related to encoded video data;', 'means for encapsulating the SEI message in an SEI NAL unit, wherein the SEI NAL unit includes a NAL unit type value that indicates whether the SEI NAL unit is a prefix SEI NAL unit or a suffix SEI NAL unit and whether the SEI message is a prefix SEI message or a suffix SEI message; and', 'means for generating a bitstream including at least the SEI NAL unit.

20. The device of claim 19, wherein the means for generating the bitstream comprises means for encapsulating the SEI NAL unit in an access unit (AU) such that the SEI NAL unit follows a first video coding layer (VCL) NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEI NAL unit is a suffix SEI NAL unit.

21. The device of claim 20, wherein the means for generating the bitstream further comprises means for encapsulating the SEI NAL unit in the AU such that the SEI NAL unit further succeeds a last VCL NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEI NAL unit is the suffix SEI NAL unit.

22. A computer-readable storage medium having stored thereon instructions that, when executed, cause a processor to:', 'determine whether a supplemental enhancement information (SEI) message is a prefix SEI message or a suffix SEI message, wherein the SEI message includes data related to encoded video data;', 'encapsulate the SEI message in an SEI NAL unit, wherein the SEI NAL unit includes a NAL unit type value that indicates whether the SEI NAL unit is a prefix SEI NAL unit or a suffix SEI NAL unit and whether the SEI message is a prefix SEI message or a suffix SEI message; and', 'generate a bitstream including at least the SEI NAL unit.

23. The computer-readable storage medium of claim 22, wherein the instructions that cause the processor to generate the bitstream comprise instructions that cause the processor to encapsulate the SEI NAL unit in an access unit (AU) such that the SEI NAL unit follows a first video coding layer (VCL) NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEI NAL unit is a suffix SEI NAL unit.

24. The computer-readable storage medium of claim 23, wherein the instructions that cause the processor to generate the bitstream further comprise instructions that cause the processor to encapsulate the SEI NAL unit in the AU such that the SEI NAL unit further succeeds a last VCL NAL unit in the AU in decoding order when the NAL unit type value indicates that the SEI NAL unit is the suffix SEI NAL unit.']