Dynamically adjusts video encoding bitrate based on network conditions using the TCP-Friendly Rate Control (TFRC) algorithm

SlowCast: Adaptive Video Streaming with TFRC

Go (golang) implementation of TCP-Friendly Rate Control for smooth and adaptive video streaming over unreliable networks.

SlowCast dynamically adjusts video encoding bitrate based on network conditions using the TCP-Friendly Rate Control (TFRC) algorithm.

This implementation follows RFC 5348 for the TFRC algorithm and RFC 8083 for RTP/RTCP extensions.

Installation on Linux (x86_64)

Prerequisites

Install required libraries:

sudo apt update
sudp apt-get update && apt-get install -y \
    gstreamer1.0-tools \
    gstreamer1.0-plugins-base \
    gstreamer1.0-plugins-good \
    gstreamer1.0-plugins-bad \
    gstreamer1.0-plugins-ugly \
    gstreamer1.0-libav \
    gstreamer1.0-x

# Clone the repository
git clone https://github.com/arsperger/slowcast.git
cd slowcast

# Build the application
go build

Usage

# Basic usage with default settings (localhost streaming)
./slowcast

# Stream to a remote host
UDP_SINK_HOST=192.168.1.100 UDP_SINK_PORT=6000 ./slowcast

# Configure source address and port
UDP_SRC_HOST=192.168.1.5 UDP_SRC_PORT=6010 ./slowcast

Configuration

SlowCast uses environment variables for configuration:

Variable	Description	Default
UDP_SINK_HOST	Destination IP for RTP stream	127.0.0.1
UDP_SINK_PORT	Destination port for RTP stream	6000
UDP_SRC_HOST	Source IP for binding	127.0.0.1
UDP_SRC_PORT	Source port for binding	7000

Additional parameters (currently hardcoded):

• Min bitrate: 500 Kbps
• Max bitrate: 4000 Kbps
• Initial bitrate: 500 Kbps
• Bitrate update interval: 500ms

Known Issues and Limitations

• Fixed packet size assumption may reduce accuracy for variable size packets
• No dynamic resolution/framerate adjustment based on bitrate changes
• new to come

Future possible improvements

• Dynamic resolution and framerate adaptation based on available bandwidth
• Better zero-loss handling algorithm (trend detection)
• Bandwidth probing for faster convergence
• Enhanced congestion detection beyond packet loss (jitter)
• Monitoring and dynamic configuration
• Implement Circuit Breakers RFC8083

Contributors

@arsperger