READ: https://medium.com/@noahschumacher/enabling-high-fidelity-low-latency-live-streaming-with-nginx-a6a4eb22ec6

This repo is a small collection of files used to build and run a dockerized NGINX-RTMP streaming server. The Dockerfile contains all specifics for building the image and the docker-compose.yml is used to quickly build and or startup a running container of the image. The specifics of the nginx server are located in nginx.conf.

Out of the box this docker images comes with:

• Streamer Validation Capabilities
• Optimized Stream Encoding
• Adaptive Bitrate Streaming
• HLS (http live streaming)

This was originally designed for a live audio-video music streaming website I was building called Muuse. At its peak we were able to handle 15+ concurrent video streamers with 1.5k+ concurrent viewers and sub 12second latency.

1. Download OBS
2. Open OBS and set the following in the Stream section:
   • Service: Custom
   • Server: rtmp://<ip-of-host>:1935/live
   • Stream Key: [paste in your stream key] (use test if not checking)
3. Start the docker-container:
   • Move to the top level of weval-nginx-rtmp
   • To run and build you image execute docker-compose up. This will utilize the docker-compose.yml.
     • If you want to be detached from the running container of the build image add -d or --detach to the above command
4. Press Start Streaming under the control panel on the right side. You should see a green or red square show up on the bottom right side of OBS followed by a kb/s number. This number informs you of your upload speed. If the square is green you are streaming with good quality. If the square is red there the upload is failing to match the pace of the stream and there will be data loss (missed frames in the stream).
5. Download and open a VLC player (it also works in Raspberry Pi using omxplayer)
   • Click in the "Media" menu
   • Click in "Open Network Stream"
   • Enter the URL from above as http://<ip_of_host>:8080/live/<key>.m3u8 replacing <ip_of_host> with the IP of the host in which the container is running and <key> with the key you created in OBS Studio. For example: http://192.168.0.30:8080/live/test.m3u8
   • Click "Play"!

You should stream your live stream coming through with some latency!

Note: If your computer does not have a fairly modern/powerful CPU it may struggle to handle encoding 3 different AV qualities. If this is the case there will be severe latency and buffering.

The docker file is based on a base ubuntu-18.04 version. At a high level it completes the following steps

1. Sets some env variables.
2. Installs some packages that allow for the downloading, compiling and execution of nginx.
3. Downloads, unpacks and compiles nginx with specific a configuration enabling nginx-rtmp and pointing to our custom nginx.conf
4. Creates some symbolic links to forwards the logs through docker.
5. Copies the local nginx.conf file to the proper location.
6. Exposes ports and starts the server.

The nginx.conf files is already highly commented to be very clear as to what each section is doing as well as how it can be altered to meet your needs. Note: this will most likely need some initial tweaking to meet your applications needs and specifications. At a high level this configuration does the following.

• Specifies 4 workers each with 10000 worker connections
• rtmp:
  • The rtmp ingest server listens on port 1935
  • application live:
    • on_publish and on_publish_done specify the endpoint to send information about a new incoming stream and a ending stream. This is useful if stream_key authorization is required.
    • Encoding:
      • In this configuration we using ffmpeg to encode 3 different qualities (2 are left commented out due to the extra CPU required to enable effective encoding).
      • There is a lot of subtleties in this ffmpeg command and if it is not setup correctly it can lead to large latencies. For instance setting keyint=60:no-scenecut was critical for me to achieve <12s latency.
      • The names of each encoding must align with the hls_variants
  • application_show:
    • This directive specifies output parameters such as the fragment and playlist length, path to the manifests, etc.
    • The hls_variant have a name and bandwidth. The bandwidth is the minimum bitrate a client needs to view the variant. It enables the client player to utilize Adaptive Bitrate Streaming.

3. http:

• This directive is where client players can obtain hls, dash, or more.
• server:
  • In this configuration we are only enabling hls live streaming.

By aligning OBS settings and the desired encoding we can further reduce compute, and latency.

The broadcast software is what takes in audio and video and sends it your streaming server. The most common software for this is called Open Broadcast Software (OBS). OBS is an incredibly powerful tool, and it’s free! Streamlabs OBS is another free option that is basically OBS with a little larger feature sweet built out. There are some paid options such as Wirecast and VidBlasterX. Though, for almost all cases, OBS/StreamlabsOBS is all you will need. The rest of this tutorial assumes you are using OBS or Streamlabs OBS as they generally the same layout and setting structure.

• To download OBS follow the guide for your operating system.
• To download Streamlabs OBS click here.

Please read through each step. Pressing "Apply" in each step will save your changes but is not required.

• Open OBS. If you have not downloaded OBS or Streamlabs OBS please refer to the above section.
• Cancel the Auto-Configuration Wizard. If it is your first time opening OBS you will be prompted with the Auto-Configuration Wizard. Press cancel if you see this.
• Navigate to the Settings. You should see the settings button on the bottom right-hand side in the controls section.
• Select the Stream section on the left side menu panel. Set the following options:
  • Service: Custom
  • Server: rtmp://<ip-of-host>:1935/live
  • Stream Key: [paste in your stream key] (use test if not checking)
• Select the Output section on the left side menu.
• Select Output Mode: Advanced. Then set the following options in the Streaming tab.
  • Audio Track: 1
  • Bitrate: 3500. Generally this should be between 2500 - 6000 depending on your Resolution and Audio qualities.
  • Keyframe Interval: 2
  • Audio tab
    • Audio Bitrate: 192 or greater. If you are going to be streaming music we recommend 224+ to ensure high quality audio.
• Select the Audio section on the left side menu.
  • Sample Rate: 44.1kHz. Only select 48kHz if you know all source input audio is also at 48kHz
  • Channels: Stereo
• Select the Video section on the left side menu.
  • Base Resolution: 1280x720. This should match your output resolution. If it does match it can increase load on your computer.
  • Output Resolution: 1280x720. It can be either 1920x1080 or 1280x720 but we recommend 720p as is good quality and does not require nearly as much *bandwidth to support.
  • FPS: 30. We do not recommend 60fps as it requires extremely reliable and strong upload capabilities. Choosing 60fps can cause a portion of your audience *to be unable to view your stream and is not currently recommended.
• Select the Advanced section on the left side menu.
  • Scroll down until you see Automatically Reconnect. Set the following options
    • Enable: selected
    • Retry Delay: 2s
    • Maximum Retries: 10
• Press okay to save your changes.
• Start the stream! Just press start streaming under the control panel on the right side. You should see a green or red square show up on the bottom right side of OBS followed by a kb/s number. This number informs you of your upload speed. If the square is green you are streaming with good quality. If the square is red there might be some buffering during specific segments.

For a more complete intro to OBS this video is great.