RTP payload format designs

1. A method of processing video data, the method comprising:

receiving a first aggregation packet according to a real-time transfer protocol (RTP), wherein the first aggregation packet comprises a payload header followed by payload data comprising a first aggregation unit and a second aggregation unit;

in response to a transmission mode for the first aggregation packet comprising a multi-session transmission mode, parsing the first aggregation unit, that is the first aggregation unit of the first aggregation packet, to determine a value for a first parameter, wherein the first parameter specifies a decoding order number for a first network abstraction layer (NAL) unit included in the first aggregation unit, wherein the first aggregation unit includes a decoding order number of least significant bits (DONL) field comprising the value for the first parameter;

parsing the second aggregation unit to determine a value for a second parameter, wherein the second aggregation unit follows the first aggregation unit in the first aggregation packet, and wherein the second parameter identifies a difference between the decoding order number for the first NAL unit included in the first aggregation unit and a decoding order number for a second NAL unit included in the second aggregation unit, wherein the second aggregation unit includes a decoding order number difference (DOND) field comprising the second value for the second parameter; and

based on the first parameter and the second parameter, determining a decoding order for the second NAL unit included in the second aggregation unit.

2. The method of claim 1 , wherein the first parameter specifies a value of a number of least significant bits of the decoding order number.

3. The method of claim 2 , wherein the value of the number is 16.

4. The method of claim 1 , wherein the second parameter plus one specifies the difference between a decoding order number of the second aggregation unit and the decoding order number of the first aggregation unit.

5. The method of claim 1 , further comprising:

parsing a third aggregation unit to determine a third parameter, wherein the third aggregation unit follows the second aggregation unit in the first aggregation packet; and

based on the second parameter and the third parameter, determining a decoding order for a third NAL unit included in the third aggregation unit.

6. The method of claim 1 , wherein parsing the first aggregation unit to determine the value for the first parameter is performed in response to a value of a third parameter being greater than 0, wherein the value for the third parameter specifies a maximum number of NAL units that precede a NAL unit in a de-packetization buffer in reception order and follow the NAL unit in decoding order.

7. The method of claim 1 , further comprising:

receiving a second aggregation packet according to the RTP protocol, wherein a transmission mode for the second aggregation packet comprises a single session transmission (SST) mode;

determining a value for a fourth syntax element is equal to zero, wherein the value of the fourth syntax element indicates a maximum number of NAL units that precede a NAL unit in a de-packetization buffer in reception order and follow the NAL unit in decoding order; and

in response to the SST mode and the fourth syntax element equaling 0, determining that a first aggregation unit of the second aggregation packet does not comprise an indication of a syntax element indicating a decoding order number.

8. A device for processing video data, the apparatus comprising:

a memory configured to store the video data;

a receiver configured to receive real-time transport protocol (RTP) packets comprising the video data;

one or more processors configured to:

receive a first aggregation packet according to a real-time transfer protocol (RTP), wherein the first aggregation packet comprises a payload header followed by payload data comprising a first aggregation unit and a second aggregation unit;

parse the first aggregation unit that is the first aggregation unit of the first aggregation packet to determine a value for a first parameter, wherein the first parameter specifies a decoding order number for a first network abstraction layer (NAL) unit included in the first aggregation unit, wherein the first aggregation unit includes a decoding order number of least significant bits (DONL) field comprising the value for the first parameter;

in response to a transmission mode for the first aggregation packet comprising a multi-session transmission mode, parse the second aggregation unit to determine a value for a second parameter, wherein the second aggregation unit follows the first aggregation unit in the first aggregation packet, and wherein the second parameter identifies a difference between the decoding order number for the first NAL unit included in the first aggregation unit and a decoding order number for a second NAL unit included in the second aggregation unit, wherein the second aggregation unit includes a decoding order number difference (DOND) field comprising the value for the second parameter; and

based on the first parameter and the second parameter, determine a decoding order for the second NAL unit included in the second aggregation unit.

9. The device of claim 8 , wherein the first parameter specifies a value of a number of least significant bits of the decoding order number.

10. The device of claim 9 , wherein the value of the number is 16.

11. The device of claim 8 , wherein the second parameter plus one specifies the difference between a decoding order number of the second aggregation unit and the decoding order number of the first aggregation unit.

12. The device of claim 8 , wherein the one or more processors are further configured to:

parse a third aggregation unit to determine a third parameter, wherein the third aggregation unit follows the second aggregation unit in the first aggregation packet; and

based on the second parameter and the third parameter, determine a decoding order for a third NAL unit included in the third aggregation unit.

13. The device of claim 8 , wherein the one or more processors are configured to parse the first aggregation unit to determine the value for the first parameter in response to a value of a third parameter being greater than 0, wherein the value for the third parameter specifies a maximum number of NAL units that precede a NAL unit in a de-packetization buffer in reception order and follow the NAL unit in decoding order.

14. The device of claim 8 , wherein the one or more processors are configured to:

receive a second aggregation packet according to the RTP protocol, wherein a transmission mode for the second aggregation packet comprises a single session transmission (SST) mode;

determine a value for a fourth syntax element is equal to zero, wherein the value of the fourth syntax element indicates a maximum number of NAL units that precede a NAL unit in a de-packetization buffer in reception order and follow the NAL unit in decoding order; and

in response to the SST mode and the fourth syntax element equaling 0, determine that a first aggregation unit of the second aggregation packet does not comprise an indication of a syntax element indicating a decoding order number.

15. The device of claim 8 , wherein the device comprises at least one of:

an integrated circuit;

a microprocessor; or

a wireless communication device that comprises a video coder.

16. A non-transitory computer-readable storage medium storing instructions that when executed by one or more processors cause the one or more processors to:

receive a first aggregation packet according to a real-time transfer protocol (RTP), wherein the first aggregation packet comprises a payload header followed by payload data comprising a first aggregation unit and a second aggregation unit;

in response to a transmission mode for the first aggregation packet comprising a multi-session transmission mode, parse the first aggregation unit that is the first aggregation unit of the first aggregation packet to determine a value for a first parameter, wherein the first parameter specifies a decoding order number for a first network abstraction layer (NAL) unit included in the first aggregation unit, wherein the first aggregation unit includes a decoding order number of least significant bits (DONL) field comprising the value for the first parameter;

parse the second aggregation unit to determine a value for a second parameter, wherein the second aggregation unit follows the first aggregation unit in the first aggregation packet, and wherein the second parameter identifies a difference between the decoding order number for the first NAL unit included in the first aggregation unit and a decoding order number for a second NAL unit included in the second aggregation unit, wherein the second aggregation unit includes a decoding order number difference (DOND) field comprising the value for the second parameter; and

based on the first parameter and the second parameter, determine a decoding order for the second NAL unit included in the second aggregation unit.

17. The non-transitory computer-readable storage medium of claim 16 , wherein the first parameter specifies a value of a number of least significant bits of the decoding order number, and wherein the number is 16.

18. The non-transitory computer-readable storage medium of claim 16 , wherein the second parameter plus one specifies the difference between a decoding order number of the second aggregation unit and the decoding order number of the first aggregation unit.

19. The non-transitory computer-readable storage medium of claim 16 , storing further instructions that when executed by the one or more processors cause the one or more processors to:

parse a third aggregation unit to determine a third parameter, wherein the third aggregation unit follows the second aggregation unit in the first aggregation packet; and

based on the second parameter and the third parameter, determine a decoding order for a third NAL unit included in the third aggregation unit.

20. The non-transitory computer-readable storage medium of claim 16 , wherein parsing the first aggregation unit to determine the value for the first parameter is performed in response to a value of a third parameter being greater than 0, wherein the value for the third parameter specifies a maximum number of NAL units that precede a NAL unit in a de-packetization buffer in reception order and follow the NAL unit in decoding order.

21. The non-transitory computer-readable storage medium of claim 16 , storing further instructions that when executed cause the one or more processors to:

receive a second aggregation packet according to the RTP protocol, wherein a transmission mode for the second aggregation packet comprises a single session transmission (SST) mode;

determine a value for a fourth syntax element is equal to zero, wherein the value of the fourth syntax element indicates a maximum number of NAL units that precede a NAL unit in a de-packetization buffer in reception order and follow the NAL unit in decoding order; and

in response to the SST mode and the fourth syntax element equaling 0, determine that a first aggregation unit of the second aggregation packet does not comprise an indication of a syntax element indicating a decoding order number.

22. A method of processing video data, the method comprising:

packetizing one or more network abstraction layer (NAL) units into a first aggregation packet according to an RTP protocol;

in response to a transmission mode for the first aggregation packet comprising a multi-session transmission mode, setting a value for a first parameter of a first aggregation unit based on a decoding order number for a first NAL unit included in the first aggregation unit, wherein the first aggregation unit includes a decoding order number of least significant bits (DONL) field comprising the value for the first parameter; and

based on a difference between a decoding order for a second aggregation unit and the decoding order number for the first aggregation unit, setting a value for a second parameter of a second aggregation unit, and wherein the second parameter identifies a difference between the decoding order number for the first NAL unit included in the first aggregation unit and a decoding order number for a second NAL unit included in the second aggregation unit, wherein the first aggregation unit includes a decoding order number difference (DOND) field comprising the value for the first parameter.

23. The method of claim 22 , wherein the first parameter specifies a value of a number of least significant bits of the decoding order number.

24. The method of claim 22 , wherein the second parameter identifies a difference between the first parameter and the decoding order number.