Stream webcam and audio source from PC via the internet to a vmix install with as little lag as possible.
This could by transport stream UDP or TCP as long as the encapsulation is mpegts and encoded with h264 and aac.
Solution ideally needs to be windows based
Using ffmpeg-20161130-4e6d1c1-win64-static.zip for 64 bit Windows, Windows 10, which includes libx264
https://ffmpeg.zeranoe.com/builds/win64/static/
ffmpeg version N-82713-g4e6d1c1 Copyright (c) 2000-2016 the FFmpeg developers
built with gcc 5.4.0 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enable-zlib
libavutil 55. 41.101 / 55. 41.101
libavcodec 57. 66.108 / 57. 66.108
libavformat 57. 58.101 / 57. 58.101
libavdevice 57. 2.100 / 57. 2.100
libavfilter 6. 67.100 / 6. 67.100
libswscale 4. 3.101 / 4. 3.101
libswresample 2. 4.100 / 2. 4.100
libpostproc 54. 2.100 / 54. 2.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
start-stream.bat
ffmpeg -loglevel error ^
-f dshow ^
-i video="USB Video Device":audio="Microphone (USB Audio Device)" ^
-vcodec libx264 ^
-preset ultrafast ^
-tune zerolatency ^
-thread_type slice ^
-slices 1 ^
-intra-refresh 1 ^
-r 30 ^
-g 60 ^
-s 800x600 ^
-aspect 4:3 ^
-acodec aac ^
-ar 44100 ^
-b:v 2.5M ^
-minrate:v 900k ^
-maxrate:v 2.5M ^
-bufsize:v 5M ^
-b:a 128K ^
-pix_fmt yuv420p ^
-f mpegts udp://192.168.0.123:35001?pkt_size=1316
Test with VLC
udp://@192.168.0.123:35001
Test with vMIX
Transport Stream over UDP
Port 35001
ffmpeg -list_devices true -f dshow -i dummy
ffmpeg installed using brew package manager on Yosemite
ffmpeg -loglevel error \
-f avfoundation \
-i "default" \
-vcodec libx264 \
-preset ultrafast \
-tune zerolatency \
-thread_type slice \
-slices 1 \
-intra-refresh 1 \
-r 30 \
-g 60 \
-s 800x600 \
-aspect 4:3 \
-acodec aac \
-ar 44100 \
-b:v 2.5M \
-minrate:v 900k \
-maxrate:v 2.5M \
-bufsize:v 5M \
-b:a 128K \
-pix_fmt yuv420p \
-f mpegts udp://192.168.0.123:35001?pkt_size=1316
ffmpeg -f avfoundation -list_devices true -i ""
Example output (Late 2013 iMac 21.5")
[AVFoundation input device @ 0x7f89b9c22920] AVFoundation video devices:
[AVFoundation input device @ 0x7f89b9c22920] [0] FaceTime HD Camera (Built-in)
[AVFoundation input device @ 0x7f89b9c22920] [1] Capture screen 0
[AVFoundation input device @ 0x7f89b9c22920] AVFoundation audio devices:
[AVFoundation input device @ 0x7f89b9c22920] [0] Built-in Microphone
ffmpeg -loglevel error - logging level (quiet, error, warning).
-f dshow - use direct show as file type.
-i video="USB Video Device":audio="Microphone (USB Audio Device)" - inputs (use ffmpeg -list_devices true -f dshow -i dummy to get list of possible sources).
-vcodec libx264 - video codec (libx264 for h264).
-acodec aac - audio codec (aac).
-preset ultrafast - encoding preset (ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo).
-tune zerolatency - tune zerolatency sends an I-Frame (complete pic) every frame so that users to not need to wait for intermetiate frames to complete.
-thread_type slice - slice-based threading tells all CPU threads work on the same frame, reducing latency a lot.
-slices 1 - has to be 1 for vMix to decode the stream, don't know why.
-intra-refresh 1 intra-refresh has to be set to 1 because vMix expects a latency of 1 frame, I think.
-r 30 - framerate.
-g 60 - GOP (Group of Pictures), simply multiply your output frame rate * 2.
-s 800x600 - scale my webcam's native picture is 1600x1200, so I scale it down.
-aspect 4:3 - aspect ratio, my webcam is a Logitec 9000 which is 4:3.
-acodec aac - audio encode using AAC.
-ar 44100 - audio sample rate 44.1 KHz.
-b:v 2.5M - desired bitrate for video 2.5 Mbps, can play with this.
-minrate:v 900k - min data rate video 900k, can play with this.
-maxrate:v 2.5M - min data rate video 2.5 Mbps, can play with this.
-bufsize:v 5M - buffer size for encoding, double max data rate seems to be a good starting point.
-b:a 128K - desired bitrate for audio 128 Kbps, can play with this.
-pix_fmt yuv420p - color space, has to be yuv420p for vMix to decode properly.
-bufsize 5000k - buffer size (double max data rate seems to be a good starting point)
-f mpegts udp://192.168.0.123:35001?pkt_size=1316 output format mpegts udp IP address, port, packet size - really important - The size of an MPEG-TS packet is 188 Bytes and 7 of them will fit into an Ethernet frame, 7*188=1316.
References
https://trac.ffmpeg.org/wiki/EncodingForStreamingSites
https://trac.ffmpeg.org/wiki/StreamingGuide
https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping
http://www.waveguide.se/?article=creating-dvb-t-compatible-mpeg2-streams-using-ffmpeg
