raspberry pi 3 Jessie OS has libav package but in case you got error try this:

apt-get install libav-tools

now insert this command:

1. Make instal VNC server
2. Vncserver :1
3. connect to linux port 5901
git clone git://git.videolan.org/x264
cd x264
./configure --host=arm-unknown-linux-gnueabi --enable-static --disable-opencl
sudo make install

cd /usr/src
git clone https://github.com/FFmpeg/FFmpeg.git
cd ffmpeg
sudo ./configure --arch=armel --target-os=linux --enable-gpl --enable-libx264--enable-nonfree
sudo make install

5. stream youtube ( find link in my website for instructions)

alias ffmpeg=avconv

To start the stream, run this command:

raspivid -o - -t 0 -w 1280 -h 720 -fps 30 -b 6000000 -g 50 | ffmpeg -re -ar 44100 -ac 2 -acodec pcm_s16le -f s16le -ac 2 -i /dev/zero -f h264 -i - -vcodec copy -acodec aac -ab 128k -g 50 -strict experimental -f flv rtmp://a.rtmp.youtube.com/live2/your youtube id find you session here" in above line in your youtube channel 
  • -o - makes it write the video data to STDOUT so it gets piped into ffmpeg.
  • -t 0 is how you make it record forever
  • -vf -hf flips it horizontal and vertical so it looks correct
  • -fps 30 sets frames per second to 30
  • -b 6000000 - output bitrate limit. YouTube recommends 400-600kbps, this is 600kbps. Change this to save upload bandwidth at the expense of a lower quality video
  • -re - tells ffmpeg to slow down the reading of the input to the native frame rate of the input (useful when live streaming)
  • -ar 44100 -ac 2 -acodec pcm_s16le -f s16le -ac 2 -i /dev/zero and -acodec aac -ab 128k and -strict experimental - adds a fake audio channel filled with zeroes (silence). YouTube rejects streams without an audio channel. You can also change the input device to a microphone if you want (I haven't done this yet)
  • -g 50 adds a keyframe every 50 frames. Feel free to tweak, its one of those tradeoff variables.
  • -f h264 and -f flv tells ffmpeg it's receiving h264 input and that you should mux it into flv output (flv is the container format that works with YouTube. Others might work but I haven't tried them)
  • by not specifying -w and -h to raspivid we get the full 1920x1080 resolution (aka 1080p). You can specify these if you want a lower resolution
automatic sending video all the time rapsberry turned on code::
while true; sudo shutdown -r +60; do nohup raspivid -o - -t 0 -w 1280 -h 720 -fps 20 -ISO auto -br auto -ex auto | ffmpeg -re -ar 44100 -ac 2 -acodec pcm_s16le -f s16le -ac 2 -i /dev/zero -f h264 -i - -vcodec copy -acodec aac -ab 128k -g 50 -strict experimental -f flv rtmp://a.rtmp.youtube.com/live2/7xxx-gxxd-xxxs-xxxk; sleep 15;reboot; done

put above code in these two places:
sudo nano /etc/rc.local
sudo nano /etc/init.d/rc.local