ffserver -f /etc/ffserver.conf &

ffmpeg -f alsa -ac 2 -i plughw:0,0 -f video4linux2 -s vga -i /dev/video0  http://localhost:8090/feed1.ffm

[...]
[tcp @ 0x560e1234c6e0] Connection to tcp://localhost:8090 failed (Connection  refused), trying next address

# ffmpeg -f alsa -ac 2 -i plughw:0,0 -f video4linux2 -s vga -i /dev/video0  http://localhost:8090/feed1.ffm

ffmpeg version 3.2.1-1 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 6.2.1 (Debian 6.2.1-5) 20161124
  configuration: --prefix=/usr --extra-version=1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-libtesseract --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-libopencv --enable-frei0r --enable-libx264 --enable-chromaprint --enable-shared
  libavutil      55. 34.100 / 55. 34.100
  libavcodec     57. 64.101 / 57. 64.101
  libavformat    57. 56.100 / 57. 56.100
  libavdevice    57.  1.100 / 57.  1.100
  libavfilter     6. 65.100 /  6. 65.100
  libavresample   3.  1.  0 /  3.  1.  0
  libswscale      4.  2.100 /  4.  2.100
  libswresample   2.  3.100 /  2.  3.100
  libpostproc    54.  1.100 / 54.  1.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, alsa, from 'plughw:0,0':
  Duration: N/A, start: 1481703954.356244, bitrate: 1536 kb/s
    Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Input #1, video4linux2,v4l2, from '/dev/video0':
  Duration: N/A, start: 41830.241126, bitrate: 147456 kb/s
    Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
[tcp @ 0x560e6432c6e0] Connection to tcp://localhost:8090 failed (Connection refused), trying next address
[tcp @ 0x560e64345a40] Connection to tcp://localhost:8090 failed (Connection refused), trying next address
[mpeg1video @ 0x560e6435fb20] bitrate tolerance 21333 too small for bitrate 64000, overriding
[mpeg1video @ 0x560e6435fb20] MPEG-1/2 does not support 3/1 fps
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> mp2 (native))
  Stream #1:0 -> #0:1 (rawvideo (native) -> mpeg1video (native))
  Stream #0:0 -> #0:2 (pcm_s16le (native) -> wmav2 (native))
  Stream #1:0 -> #0:3 (rawvideo (native) -> msmpeg4v3 (msmpeg4))
Error while opening encoder for output stream #0:1 - maybe incorrect parameters such as bit_rate, rate, width or height

HTTPPort 8090
HTTPBindAddress 0.0.0.0
MaxHTTPConnections 2000
MaxClients 1000
MaxBandwidth 1000
CustomLog -
<Feed feed1.ffm>
File /tmp/feed1.ffm
FileMaxSize 200K
ACL allow 127.0.0.1
</Feed>
<Stream test1.mpg>
Feed feed1.ffm
Format mpeg
AudioBitRate 32
AudioChannels 1
AudioSampleRate 44100
VideoBitRate 64
VideoBufferSize 40
VideoFrameRate 3
VideoSize 160x128
VideoGopSize 12
</Stream>
<Stream test.asf>
Feed feed1.ffm
Format asf
VideoFrameRate 15
VideoSize 352x240
VideoBitRate 256
VideoBufferSize 40
VideoGopSize 30
AudioBitRate 64
StartSendOnKey
</Stream>
<Stream stat.html>
Format status
ACL allow localhost
ACL allow 192.168.0.0 192.168.255.255
</Stream>
<Redirect index.html>
URL http://www.ffmpeg.org/
</Redirect>

Port 8090
# bind to all IPs aliased or not
BindAddress 0.0.0.0
# max number of simultaneous clients
MaxClients 1000
# max bandwidth per-client (kb/s)
MaxBandwidth 10000
# Suppress that if you want to launch ffserver as a daemon.
NoDaemon

<Feed feed1.ffm>
File /tmp/feed1.ffm
FileMaxSize 5M
</Feed>

<Stream test.swf>
Feed feed1.ffm
Format swf
VideoCodec flv
VideoFrameRate 15
VideoBufferSize 80000
VideoBitRate 100
VideoQMin 1
VideoQMax 5
VideoSize 352x288
PreRoll 0
Noaudio
</Stream>