avcapture

avcapture allows you to run a that captures the content and pipes the audio/video for any URL to FFmpeg for encoding including generating a live playlist.

Build and Run

Build: make build
Run: docker run -it --net test -v $PWD/path/to/dir:$PWD/path/to/dir --name avcapture -p 8080:8080 etherlabsio/avcapture

API

start-recording

POST: http://IP:8080/start_recording
"ffmpeg:options" and "chrome:options" are optional. If it is specified, the original arguments to these applications will be replaced completely with the provided one. User has to take care on the arguments passed for proper functionality.

{
  "ffmpeg": {
    "params": [
      [" -hls_time", "6"],
      ["-hls_playlist_type", "event"],
      ["-hls_segment_filename", "/work/out%04d.ts"],
      ["/work/play.m3u8"]
    ],
    "options": [
      ["-y", ""],
      ["-v", "info"],
      ["-f", "x11grab"],
      ["-draw_mouse", "0"],
      ["-r", "24"],
      ["-s", "1280x720"],
      ["-thread_queue_size", "4096"],
      ["-i", ":99.0+0,0"],
      ["-f", "pulse"],
      ["-thread_queue_size", "4096"],
      ["-i", "default"],
      ["-acodec", "aac"],
      ["-strict", "-2"],
      ["-ar", "48000"],
      ["-c:v", "libx264"],
      ["-x264opts", "no-scenecut"],
      ["-preset", "veryfast"],
      ["-profile:v", "main"],
      ["-level", "3.1"],
      ["-pix_fmt", "yuv420p"],
      ["-r", "24"],
      ["-crf", "25"],
      ["-g", "48"],
      ["-keyint_min", "48"],
      ["-force_key_frames", "\"expr:gte(t,n_forced*2)\""],
      ["-tune", "zerolatency"],
      ["-b:v", "3600k"],
      ["-maxrate", "4000k"],
      ["-bufsize", "5200k"]
    ]
  },
  "chrome": {
    "url": "<https://www.youtube.com/watch?v=Bey4XXJAqS8>",
    "options": [
      "--enable-logging=stderr",
      "--autoplay-policy=no-user-gesture-required",
      "--no-sandbox",
      "--start-maximized",
      "--window-position=100,300",
      "--window-size=1280,720"
    ]
  }
}

stop-recording

POST: http://IP:8080/stop_recording
No parameter is passed to this call.

Configuration

By default, the application will run server on port 8080. If the application has to run on a different port, set the environment variable PORT with the new port inside the Dockerfile before the ENTRYPOINT. For example:

ENV PORT=":8080"

Output

User is supposed to map a directory from host system to the docker image. Along with this, user has to provide the output path (as part of /start_recording api) which will direct the output generated to the corresponding directory.

Architecture

The docker image contains google chrome, ffmpeg and wrapper application. As part of startup, the wrapper application will configure the system to run chrome browser on the given display id and to capture audio using pulseaudio. Once the /start_recording is received, chrome will be started to render the url provided. An instance of ffmpeg will be started to capture the display.

Version Info

Component	Version	Details
Base docker image	ubuntu:16.04
ffmpeg	4.0.2	https://ffmpeg.org/releases/ffmpeg-4.0.2.tar.bz2
libx264	latest	git://git.videolan.org/x264.git
nasm	2.13.03	https://www.nasm.us/pub/nasm/releasebuilds/2.13.03/nasm-2.13.03.tar.bz2
Google chrome	Latest stable	deb http://dl.google.com/linux/chrome/deb/ stable main
pulseaudio	8.0

Known limitations

The solution is validated on ubuntu 16.04 (with pulseaudio v8.0). Ubuntu 18.04 contains pulseaudio 11.1 which breaks a few features. With pulseaudio 11.1,
To run pulseaudio as daemon on root, --system has to be mentioned.
User will not be able to add modules to pulseaudio.

bandronic/avcapture