Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/third_party/libwebrtc/docs/native-code/rtp-hdrext/video-timing/README.md b/third_party/libwebrtc/docs/native-code/rtp-hdrext/video-timing/README.md
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+# Video Timing
+
+The Video Timing extension is used to communicate a timing information on
+per-frame basis to receiver of rtp video stream. Contact <ilnik@google.com> for
+more info. It may be generalized to audio frames as well in the future.
+
+Name: "Video Timing" ; "RTP Header Extension for Video timing"
+
+Formal name: <http://www.webrtc.org/experiments/rtp-hdrext/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:
+
+  * 0x01 - extension is set due to timer.
+  * 0x02 - extension is set because the frame is larger than usual.
+
+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:
+
+  * Encode start.
+  * Encode finish.
+  * Packetization complete.
+  * Last packet left the pacer.
+  * Reserved for network.
+  * Reserved for network (2).
+
+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.