Trying to understand the latency tracer

[solo_juan]

I have the same problem, I don't know how to interpret the data. For example:

The data:

- Rasberry Pi 3
- Raspbian Buster
- Raspberry Camera Module V2
- gstreamer, version 1.17.0.1
- Capture data: Motion-JPEG, 426x240, 15 fps and 429000 bps of bitrate

Pipeline:

/opt/vc/bin/raspivid -t 60000 -cd MJPEG -w 426 -h 240 -fps 15 -b 429000 -vf
-hf \
-o - | GST_DEBUG="GST_TRACER:7" GST_DEBUG_FILE=240.log
GST_TRACERS="latency(flags=pipeline+element+reported)" \
gst-launch-1.0 -v  fdsrc do-timestamp=true ! \
"image/jpeg,width=426,height=240,framerate=15/1,payload=(int)26" ! \
jpegparse ! rtpjpegpay ! \
udpsink port=13000 host=192.168.1.111 && gst-stats-1.0 240.log


The output:

Latency Statistics:
0x20340f0.fdsrc0.src|0x20ff150.udpsink0.sink: mean=0:00:00.001291400
min=0:00:00.000751041 max=0:00:00.007009887

Element Latency Statistics:
0x21040f0.capsfilter0.src: mean=0:00:00.000236961 min=0:00:00.000096875
max=0:00:00.000554530
0x20ec2d0.jpegparse0.src: mean=0:00:00.000558282 min=0:00:00.000346250
max=0:00:00.006139732
0x20f80b8.rtpjpegpay0.src: mean=0:00:00.000458047 min=0:00:00.000248542
max=0:00:00.004859044

Element Reported Latency:
0x20340f0.fdsrc0: min=0:00:00.000000000 max=0:00:00.000000000
ts=0:00:00.644349393
0x21040f0.capsfilter0: min=0:00:00.000000000 max=0:00:00.000000000
ts=0:00:00.644468508
0x20ec2d0.jpegparse0: min=0:00:00.000000000 max=0:00:00.000000000
ts=0:00:00.644528403
0x20f80b8.rtpjpegpay0: min=0:00:00.000000000 max=99:99:99.999999999
ts=0:00:00.644595383


My interpretation of the measure:

- it takes 644.3 ms to receive the data stream from the camera.
- it takes 0,06 ms to run jpegparse.


Is this interpretation of the data correct? If so, why does it take so long
to acquire the flow?






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