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howto reduce latency

Posted: 03 Nov 2013 10:55
by mdrslmr
Hi,

I'm using vlc/vlm as streaming server. Vlc/vlm introduces
some latency of approximately 1 to 1.5 seconds. Do you
have a hint how to reduce this latency?

In more detail:
I have several IP cameras and one decoder with an attached monitor.
A java application controls which of the IP cameras
is displayed via the decoder. Vlc/vlm provides the software API
actually controlling the streams via "--intf rc". The command line
looks like this:

Code: Select all

vlc -I dummy --intf rc --extraintf telnet --sout-keep --network-caching 50 --live-caching 0 --no-audio --no-sout-audio
The decoder always gets the stream from vlc. The camera streamed by vlc
is selected by the java application by issuing e.g. "control camera1 play"
via the rc interface.

The attached file is similar to the configuration I use.

Any ideas on how to reduce the latency or other improvements?

For comparison: when bypassing vlc and linking a IP camera to the decoder by
some static configuration the latency almost not noticeable.

Code: Select all

# vlc version 2.0.3-5~bpo60+2 # invocation # /usr/bin/vlc -I dummy --intf rc --extraintf telnet --sout-keep --network-caching 50\ # --live-caching 0 --no-audio --no-sout-audio new camera1 broadcast enabled setup camera1 input "rtsp://<user>:<pwd>@hcamera1.example.org/MediaInput/h264" setup camera1 output #gather:rtp{dst=myvideodecoder.example.org,port=6004} setup camera1 option sout-keep setup camera1 option input-repeat=-1 new camera2 broadcast enabled setup camera2 input "rtsp://<user>:<pwd>@camera2.example.org/MediaInput/h264" setup camera2 output #gather:rtp{dst=myvideodecoder.example.org,port=6004} setup camera2 option sout-keep setup camera2 option input-repeat=-1 new camera3 broadcast enabled setup camera3 input "rtsp://<user>:<pwd>@camera3.example.org/MediaInput/h264" setup camera3 output #gather:rtp{dst=myvideodecoder.example.org,port=6004} setup camera3 option sout-keep setup camera3 option input-repeat=-1 new camera4 broadcast enabled setup camera4 input "rtsp://<user>:<pwd>@camera4.example.org/MediaInput/h264" setup camera4 output #gather:rtp{dst=myvideodecoder.example.org,port=6004} setup camera4 option sout-keep setup camera4 option input-repeat=-1

Re: howto reduce latency

Posted: 03 Nov 2013 20:30
by mdrslmr
I just found "multicat" may be sufficient for my needs. But as far as I can
tell (since there is no software API) for switching the camera this would
mean to kill a running multicat process and to create a new one for the new
camera. This would not be very elegant.