Latency Measurements

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RidgeRun GstMoQ: Media Over Quic GStreamer Plugin

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Latency tests

We measure glass-to-glass latency using v4l2src and a video with a timeoverlay. Multiple samples are taken, also we measure latency under different conditions, for example publishing multiple streams or on a one-to-many setup as well as using rrmoqsrc and web-server. These are not perfect measurements but it helps us get a rough idea of the latency.

The video with timeoverlay is generated with the following pipeline:

gst-launch-1.0 -e \
  filesrc location=bunny.mp4  ! qtdemux name=d \
    d.video_0 ! queue ! decodebin ! videoconvert \
      ! timeoverlay halignment=left valignment=top time-mode=buffer-time \
      ! x264enc speed-preset=veryfast bitrate=2500 key-int-max=60 bframes=0 \
      ! h264parse ! queue ! mux. \
    d.audio_0 ! queue ! aacparse ! queue ! mux. \
    mp4mux name=mux faststart=true ! filesink location=bunny_with_clock.mp4

Then we use a tee to see the video that being send through moq roughly at the same time:

gst-launch-1.0 -v \
  filesrc location=bunny_with_clock.mp4 \
    ! qtdemux name=demux \
    demux.video_0 \
    ! h264parse \
    ! tee name=t \
    \
    t. ! queue \
       ! h264parse config-interval=-1 \
       ! rrmoqsink relay-url="http://127.0.0.1:4443" channel=test \
    \
    t. ! queue \
       ! vaapidecodebin \
       ! vaapipostproc \
       ! xvimagesink

With live videosrc:

gst-launch-1.0 -v \
  autovideosrc  \
    ! vaapipostproc ! timeoverlay halignment=left valignment=top  \
    ! tee name=t \
    \
    t. ! queue \
       ! vaapipostproc \
       ! xvimagesink \
    \
    t. ! queue \
       ! vaapipostproc \
       ! timeoverlay halignment=left valignment=top ! vaapih264enc   \
       ! h264parse  \
       ! rrmoqsink relay-url="http://127.0.0.1:4443" channel=test

We consume the video track and check the time difference between the two in the timeoverlay added.

gst-launch-1.0 -v \
  rrmoqsrc relay-url=https://127.0.0.1:4443 channel=test name=src \
  src.track ! queue  \
    ! vaapidecodebin  \
    ! vaapipostproc ! xvimagesink sync=false

For the web-server case with video we use the following pipeline:

gst-launch-1.0 \
  filesrc location=../bbb_with_clock_baseline.mp4 ! \
  qtdemux name=mux \
    mux.video_0 ! tee name=t \
   t. ! queue ! \
      rrmoqbin relay-mode=local relay-server-host-addr=https://127.0.0.1:4443 \
        channel=web-test name=bin sink_0::track-name=video run-web-server=true     \
   t. ! queue \
      ! vaapidecodebin \
      ! vaapipostproc \
      ! xvimagesink

And with autovideosrc:

gst-launch-1.0 -v \
  autovideosrc  \
    ! vaapipostproc ! timeoverlay halignment=left valignment=top  \
    ! tee name=t \
    \
    t. ! queue \
       ! vaapipostproc \
       ! xvimagesink \
    \
    t. ! queue \
       ! vaapipostproc \
       ! timeoverlay halignment=left valignment=top ! x264enc tune=zerolatency speed-preset=ultrafast  ! video/x-h264,profile=baseline ! rrmoqbin relay-mode=local  relay-server-host-addr=https://127.0.0.1:4443 \
        channel=web-test name=bin sink_0::track-name=video run-web-server=true

And view the video in http://127.0.0.1:5173/.

This gives us a set of measuremnets under different conditions:

Peer-to-peer (rrmoqsrc)

Item	Resolution	Framerate	Bitrate	Latency (Local relay)	Latency (VPN relay)
Video A	1280x720	24 fps	~2.17 Mbps	samples: [0.29 s, 0.50 s, 0.65 s]	samples: [0.75 s, 0.83 s, 2.00 s]
v4l2src	640×480	30 fps	~0.5 Mbps	samples: [0.564 s, 0.236 s, 0.5 s]	(xvimagesink sync=false) [0.068 s, 0.1 s, 0.1 s]

Peer-to-peer (web-server)

Item	Resolution	Framerate	Bitrate	Latency (Local relay)	Latency (VPN relay)
Video A	1280x720	24 fps	~1.99 Mbps	samples: [0.125 s, 0.125 s, 0.084 s]	samples: [0.125 s, 0.125 s, 0.125 s]
v4l2src	640×480	30 fps	~0.5 Mbps	samples: [0.1s, 0.1s, 0.1s]	[0.032 s, 0.1 s, 0.1 s]

One-to-many (rrmoqsrrc)

For this test we launch a single track to a local relay and get latency measurements from 5 rrmoqsrc elements running simultanously in the same computer.

Item	Resolution	Framerate	Bitrate	Latency
Video A	1280x720	24 fps	~1.99 Mbps	samples: [0.542 s, 1.50 s, 0.084 s, 0.50 s, 0.792 s]

One-to-many (web-server)

This test launched a single track with a local relay and 5 web pages consuming the track:

Item	Resolution	Framerate	Bitrate	Latency
Video A	1280x720	24 fps	~1.99 Mbps	samples: [0.1s, 0.1s, 0.1s. 0.1s, 0.005s]

One-to-one high traffic

This test runs in a one-to-one setup but we launched multiple tracks 10 tracks (same video and different channel) in the same relay server to see the behavior under higher traffic.

For this test we launch a single track to a local relay and get latency from 5 rrmoqsrc elements running simultanously in the same computer.

Item	Resolution	Framerate	Bitrate	Latency
Video A	1280x720	24 fps	~2.17 Mbps	samples: [0.833 s, 1.625 s, 1.166 s]

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