Streamy Process Node

This is a process node for Streamy. The purpose of a dedicated process node is to allow any number of processing nodes to run on separate servers, decoupling these tasks from user request handling.

How It Works

The Streamy project is responsible for handling user requests and managing various functionalities such as video creation, channels, comments, profiles, and more.

There is a different project, Streamy Process Node responsible for running long processes.

The Streamy Process Node takes on the responsibility of executing long-running processes. Here's how it works:

Video Uploads:

1. When a new video is uploaded, Streamy sends a message to the Process Node containing the video details.
2. The Process Node downloads the video from Minio.
3. It then processes and transcodes the video into HLS (HTTP Live Streaming) format.

Live Streaming:

1. When a new stream hits SRS (Simple Realtime Server), it is handed over to the Process Node.
2. The node transcodes the stream into HLS format as well using FFMPEG.

This separation of concerns ensures that user interactions remain responsive, while the heavy lifting of video processing is handled efficiently by dedicated nodes.

Installation

There is a docker compose file in the project, to use it you must already have docker installed.

Step 1: Configure Environment Variables

1. Rename app.env.example to app.env and .env.example to .env.
2. Fill out the .env and app.env files with the required environment variables. Descriptions for each variable are provided within the files.
   • .env is used by the Docker Compose file.
   • app.env is the primary environment file used by the application.

Step 2: Start up dependencies

Run the Docker Compose file to start up the necessary dependencies:

sudo docker compose up -d

Step 3: Install Packages and Run the Application

Installing dependencies:

chmod 755 setup.sh
./setup.sh

Start the application:

npm start

The application will be available on the port specified in the .env file. You can route traffic to the app using Nginx.

Details of video processing

Command 1: VOD Processing

The first command takes the uploaded video as input and outputs three variants of the video, each with its associated M3U8 files and a final master M3U8 file. These variants are created in different qualities and resolutions to enable adaptive bitrate streaming for the user.

• Resolutions: The uploaded 1080p video is resized to 1080p, 720p, and 360p.
• Bitrates: Each variant is assigned a suitable bitrate to balance file size and quality. These bitrates can be adjusted as needed without breaking the process.
• Video Codec: The H.264 codec (libx264) is used. H.265 (HEVC) can be used in newer versions of HLS if desired.
• Audio Codec: The AAC codec is used for audio.
• Segmentation: Using the single_file option, segmentation is done through byte range instead of creating separate segments.

These steps ensure that the video player can provide adaptive bitrate streaming, delivering the best possible quality based on the user's network conditions.

ffmpeg -hide_banner -loglevel info -y -threads 8 -i ./video.mp4  -codec:v libx264 -crf:v 23 -profile:v high -pix_fmt:v yuv420p -rc-lookahead:v 40 -force_key_frames:v expr:'gte(t,n_forced*2.000)' -preset:v "veryfast" -b-pyramid:v "strict"   -filter_complex "[0:v]fps=fps=30,split=3[v1][v2][v3];[v1]scale=width=-2:height=1080[1080p];[v2]scale=width=-2:height=720[720p];[v3]scale=width=-2:height=360[360p]"  -map "[1080p]" -maxrate:v:0 2500000 -bufsize:v:0 5000000 -level:v:0 4.0  -map "[720p]" -maxrate:v:1 1700000 -bufsize:v:1 3200000 -level:v:1 3.1  -map "[360p]" -maxrate:v:2 800000 -bufsize:v:2 1600000 -level:v:2 3.1  -codec:a aac -ar 44100 -ac:a 2  -map 0:a:0 -b:a:0 192000  -map 0:a:0 -b:a:1 128000  -map 0:a:0 -b:a:2 96000  -f hls  -hls_flags +independent_segments+program_date_time+single_file  -hls_time 6  -hls_playlist_type vod  -hls_segment_type mpegts  -master_pl_name 'master.m3u8'  -var_stream_map 'v:0,a:0,name:1080p v:1,a:1,name:720p v:2,a:2,name:360p'  -hls_segment_filename 'segment_%v.ts' 'manifest_%v.m3u8'

Command 2: Subtitle Processing

The second command is used whenever a new subtitle is uploaded.

• Subtitle Integration: The sgroup feature in FFMPEG is employed to integrate subtitles into the HLS packaging. However, since this feature is relatively new and lacks full functionality, it is used only for processing and segmenting the subtitles and the associated M3U8 file.
• Heartbeat for Segmentation: The video is used as a heartbeat for segmentation to ensure accurate subtitle segmentation. Without the heartbeat, the segmentation would be imperfect.
• Manual Master File Update: The tag for the new subtitle is manually added to the master M3U8 file using the m3u8-parser package. which I forked to add stringify feature.

One downside to this approach is that using the video as a heartbeat generates redundant videos that are identical to the input video. These redundant videos are named with a prefix "redundant" for easy identification and deletion afterwards.

ffmpeg -hide_banner  -threads 8 -loglevel info -y -i ./video.mp4 -i ./sub.srt -c:v copy -c:s webvtt  -map 0:v  -map 1:s -f hls -hls_time 6 -hls_playlist_type vod -hls_subtitle_path sub_vtt_%v.m3u8 -hls_segment_type mpegts -var_stream_map 'v:0,s:0,name:${langCode},sgroup:subtitle' -hls_segment_filename 'redundant_%v_%04d.ts' sub_vtt_%v.m3u8

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

GNU General Public License v3.0