Streaming live TV with low delay

This is a currently ongoing project of mine. My target is to have the picture (and maybe the audio as well, but the main focus is on the picture) captured from the output of my home theater and then streamed across my home network in order to be able to broadcast the picture in low quality to small touch screen devices while it is also playing in high definition on the main screen. i therefore want to have no noticeable delay between the hd picture and the broadcasted picture because i want to keep the pictures of all screens in sync with the audio which is hearable across several rooms..

currently i take the composite video signal directly off my sd tv tuner box and capture it with a hauppauge win-tv on my linux server from where i am trying to broadcast it with VLC to the client on my desktop pc. so the only things to add delay to the whole chain are currently the capturing card, the broadcasting computer and the receiving computer… no sclaer or anything else yet.

currently i am stuck with a delay of a little more than one second and i don't know if this is due to the capturing card or if it could be configured away with clever arguments on the software side.

to further investigate i will have to install the card from the server in my desktop machine and try the delay when viewing the image locally without the broadcast..

here is the command line i use on the server side to broadcast the image (no audio)

cvlc v4l2:// :v4l2-dev=/dev/video0 :v4l2-input=1 :v4l2-caching=60 :v4l2-fps=12 :v4l2-height=240 :v4l2-width=320 --sout="#transcode{vcodec=mp4v,vb=800,scale=1,acodec=none}:std{access=udp,mux=ts,udp-cache=10,cache=10,caching=10,dst=}"

on the client side i set the cache to 1ms as well by changing it under advanced options in the vlc player.

currently all the cache arguments in the std{} block did not change anything..but te v4l2-caching seems to be at its minimum when on 60ms everything below this gets a lossy stream or no stream at all from the card.

  • streaming_live_tv_with_low_delay.txt
  • Last modified: 10.02.2010 01:14
  • by Pascal Suter