How to reduce the latency

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
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1

How to reduce the latency? Here is the test command:
gst-launch-1.0 v4l2src device=“/dev/video0” ! ‘video/x-raw, width=1920,height=1080,format=(string)UYVY’ ! nvvidconv ! “video/x-raw(memory:NVMM),width=1920,height=1080,format=(string)I420” ! nvv4l2h264enc maxperf-enable=1 bitrate=8000000 preset-level=0 num-B-Frames=0 ! nvv4l2decoder enable-max-performance=1 disable-dpb=1 ! nvoverlaysink sync=false max-lateness=-1

I found the latency is about 110ms(1080P60). Is it the right command or it’s the right result?

3

Hi,
It looks to be optimal gstreamer command. Both encoder and decoder run in max clocks. You may compare to the case without encoder and decoder:

gst-launch-1.0 v4l2src device="/dev/video0" ! "video/x-raw, width=1920,height=1080,format=(string)UYVY" ! nvvidconv ! "video/x-raw(memory:NVMM),width=1920,height=1080,format=(string)I420" ! nvoverlaysink sync=false max-lateness=-1
4

No encoder and decoder is about 70ms(1080P60). But I want to test the encoder latency and the decoder latency. That means encoder and decoder need about 50ms? And how can I reduce the latency or any suggestions?

5

@DaneLLL
Is the multimedia api faster than gstream? Because I found the multimedia api latency is less than gst-launch-1.0 command. The capture and display test, the multimedia api is about 40ms, when I set the jetson_clocks. Because my project is sensitive on speed, so I must confirm that. It’s better less than 50ms(capture->convert->encoder->decoder->display)

6

Hi,
Generally jetson_mutlimedia_api is faster than gstreamer. It it low-level APIs and goes through less layers when comparing to gstreamer. You may check samples in

/usr/src/jetson_multimedia_api