The Video Timing extension is used to communicate a timing information on per-frame basis to receiver of rtp video stream. Contact firstname.lastname@example.org for more info. It may be generalized to audio frames as well in the future.
Name: “Video Timing” ; “RTP Header Extension for Video timing”
SDP “a= name”: “video-timing” ; this is also used in client/cloud signaling.
Wire format: 1-byte extension, 13 bytes of data. Total 14 bytes extra per packet (plus 1-3 padding byte in some cases, plus shared 4 bytes for all extensions present: 2 byte magic word 0xBEDE, 2 byte # of extensions).
First byte is a flags field. Defined flags:
Both flags may be set at the same time. All remaining 6 bits are reserved and should be ignored.
Next, 6 timestamps are stored as 16-bit values in big-endian order, representing delta from the capture time of a packet in ms. Timestamps are, in order:
Pacer timestamp should be updated inside the RTP packet by pacer component when the last packet (containing the extension) is sent to the network. Last two, reserved timstamps, are not set by the sender but are reserved in packet for any in-network RTP stream processor to modify.
Notes: Extension shoud be present only in the last packet of video frames. If attached to other packets it should be ignored.