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AndiThebest is offline AndiThebest
2011-01-19 , 22:49
Posts: 203 | Thanked: 152 times | Joined on May 2009 @ Austria
#1
Hi.

I want make a argumented reality car, controled by n900 accelerometer.
So i have a embedded debian board with makes a wlan-accesspoint, controls the car and sends a webcam stream to n900.

I have testet videostream from my laptop webcam to n900 (server and client = vlc) with 3 different ways:

Code:
server rtp:
vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp2v,acodec=mpga}:rtp{dst=CLIENTADRESSE,port=5000,sdp=file:///home/andi/sdp.sdp,ttl=10,mux=ts,proto=udp}'

client rtp:
open sdp.sdp file, generated by server
vlc file:///sdp.sdp

Code:
server udp multicast:
vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp2v,vb=800,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:std{access=udp,mux=ts,dst=239.255.23.23:1234}'

client:
vlc udp://@239.255.23.23:1234 :udp-caching=0

Code:
server mms stream:
vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp2v,vb=64,scale=1,acodec=mpga,ab=8,channels=1}:std{access=mmsh,mux=asfh,dst=:8080}'

client (n900, kmplayer, gstreamer/mplayer):
mms://SERVER:8080
via vlc:
vlc mmsh://SERVER:8080
My problem is, delay between webcam and n900(kmplayer/vlc) is ~2 seconds, thats too long.
Any ideas to decrase this latency?

Regards, Andi
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aligatro is offline aligatro
2011-01-19 , 22:57
Posts: 490 | Thanked: 191 times | Joined on May 2010
#2
try to send uncompressed video, that should help, but wifi might be too slow for it.
 
epitaph is offline epitaph
2011-01-19 , 23:03
Banned | Posts: 358 | Thanked: 160 times | Joined on Dec 2010
#3
Originally Posted by AndiThebest View Post
Hi.

I want make a argumented reality car, controled by n900 accelerometer.
So i have a embedded debian board with makes a wlan-accesspoint, controls the car and sends a webcam stream to n900.

I have testet videostream from my laptop webcam to n900 (server and client = vlc) with 3 different ways:

Code:
server rtp:
vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp2v,acodec=mpga}:rtp{dst=CLIENTADRESSE,port=5000,sdp=file:///home/andi/sdp.sdp,ttl=10,mux=ts,proto=udp}'

client rtp:
open sdp.sdp file, generated by server
vlc file:///sdp.sdp

Code:
server udp multicast:
vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp2v,vb=800,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:std{access=udp,mux=ts,dst=239.255.23.23:1234}'

client:
vlc udp://@239.255.23.23:1234 :udp-caching=0

Code:
server mms stream:
vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp2v,vb=64,scale=1,acodec=mpga,ab=8,channels=1}:std{access=mmsh,mux=asfh,dst=:8080}'

client (n900, kmplayer, gstreamer/mplayer):
mms://SERVER:8080
via vlc:
vlc mmsh://SERVER:8080
My problem is, delay between webcam and n900(kmplayer/vlc) is ~2 seconds, thats too long.
Any ideas to decrase this latency?

Regards, Andi
u can use my tune-up utilities! it optimize network stack and install iptables and iproute. Other than that reduce color of webcam or compute all data onboard ( do u need a life image anyway ? ).

BTW: do u have fleury or hierholzer algo in php? i really need it!
Last edited by epitaph; 2011-01-19 at 23:23.
 
AndiThebest is offline AndiThebest
2011-01-19 , 23:35
Posts: 203 | Thanked: 152 times | Joined on May 2009 @ Austria
#4
thanks for fast replys!

Originally Posted by aligatro View Post
try to send uncompressed video, that should help, but wifi might be too slow for it.
Its not possible to stream without transcoding... when i use vlc without the transcode parameter:
Code:
vlc -vvv v4l2:///dev/video0 --sout '#std{access=udp,mux=ts,dst=239.255.23.23:1234}'
I'll get this output:

Code:
[0x29e1f68] main mux debug: adding a new input
[0x29e1f68] mux_ts mux debug: adding input codec=YUY2 pid=68
[0x29e1f68] main mux error: cannot add this stream
[0x29eb958] main packetizer error: cannot create packetizer output (YUY2)



u can use my tune-up utilities! it optimize network stack and install iptables and iproute. Other than that reduce color of webcam or compute all data onboard ( do u need a life image anyway ? ).

BTW: do u have fleury or hierholzer algo in php? i really need it!
Do you know how can i reduce quality and colors of the webcam? yes i want to have a life image.
btw: i am a php newbie
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epitaph is offline epitaph
2011-01-19 , 23:45
Banned | Posts: 358 | Thanked: 160 times | Joined on Dec 2010
#5
i don't know. it should be some sort of freq filter on the server site. can't u just pipe video device through mplayer on server first i.e. preproccesing and then stream it with vlc? i don't have a fast algo here. also if u use my script u can get very low latency ping and upload dunno how much u can increase throughput but if u are really into it u should try it?
Last edited by epitaph; 2011-01-19 at 23:48.
 
aligatro is offline aligatro
2011-01-19 , 23:45
Posts: 490 | Thanked: 191 times | Joined on May 2010
#6
I didn't test this, but it might work.

Modified your server settings to

vlc -vvv v4l2:///dev/video0 --sout '#transcode{vcodec=mp1v,acodec=mpga,fps=10,vb=200} :rtp{dst=CLIENTADRESSE,port=5000,sdp=file:///home/andi/sdp.sdp,ttl=10,mux=ts,proto=udp}'

Frames per second is 10, bitrate is 200 kb/s and changed codec to Mpeg1.
 
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