System Architecture

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Overview

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High-Level Architecture

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Core Components

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1. Application Adapter

public class AntMediaApplicationAdapter extends MultiThreadedApplicationAdapter 
    implements IAntMediaStreamHandler, IShutdownListener {

• Accept incoming connections (RTMP, WebRTC, SRT)
• Authenticate publishers and viewers
• Manage stream lifecycle
• Coordinate between components
• Handle webhook callbacks

• Multi-threaded request handling
• Stream security filters
• Cluster communication
• Analytics integration

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2. Stream Adaptors

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RTMPAdaptor

public class RTMPAdaptor extends Adaptor {
    // Processes RTMP handshake and media packets
    // Extracts audio/video streams
    // Forwards to MuxAdaptor
}

• RTMP handshake negotiation
• FLV tag parsing
• Audio/video stream extraction
• Metadata processing

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SRTAdaptor

public class SRTAdaptor {
    // Handles SRT protocol with ARQ
    // Provides error correction
    // Maintains stream quality over unreliable networks
}

• Automatic Repeat Request (ARQ)
• Forward Error Correction (FEC)
• Encryption support
• Latency control

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WebRTC Adaptor

public interface IWebRTCAdaptor {
    // SDP offer/answer negotiation
    // ICE candidate exchange
    // DTLS/SRTP media handling
}

• Signaling server integration
• STUN/TURN server communication
• RTP packet processing
• RTCP statistics collection

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3. MuxAdaptor

public class MuxAdaptor {
    // Coordinates all muxers
    // Manages encoding pipeline
    // Handles stream distribution
}

• Initialize muxers for each output format
• Coordinate transcoding operations
• Distribute packets to all active muxers
• Monitor stream health
• Manage adaptive bitrate profiles

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4. Muxers

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HLSMuxer

public class HLSMuxer extends Muxer {

• Generate M3U8 playlists
• Create TS or fMP4 segments
• Manage segment rotation
• Upload to S3/CDN
• Support for low-latency HLS

private boolean hlsMuxingEnabled = true;
private String hlsListSize = "15";
private String hlsTime = "2";
private String hlsPlayListType = null;
private String hlsSegmentType = HLS_SEGMENT_TYPE_MPEGTS;

segmentFilename = httpEndpoint + "/" + subFolder + "/" + streamName + segmentSuffix + ".ts";

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Mp4Muxer

public class Mp4Muxer extends Muxer {
    // Creates MP4 container
    // Handles moov atom positioning
    // Manages file rotation
}

• Fast-start MP4 (moov before mdat)
• Automatic file rotation
• Date/time stamped filenames
• Cloud storage upload

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RecordMuxer

public class RecordMuxer extends Muxer {
    // Manages MP4 and WebM recording
    // Handles simultaneous recording
}

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WebMMuxer

public class WebMMuxer extends Muxer {
    // VP8/VP9 video support
    // Vorbis/Opus audio support
}

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5. Encoder/Transcoder

private String encoderName = ""; // Auto-detect: h264_nvenc, libx264, etc.

• h264_nvenc - NVIDIA NVENC
• h264_qsv - Intel Quick Sync
• h264_vaapi - Linux VA-API
• h264_videotoolbox - Apple VideoToolbox

• libx264 - H.264 software encoder
• libopenh264 - Cisco OpenH264
• libvpx - VP8/VP9 encoder

public class EncoderSettings {
    private int height;
    private int videoBitrate;
    private int audioBitrate;
    private boolean forceEncode = true;
}

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6. DataStore

public interface DataStore {
    // Save/retrieve broadcast info
    // Manage stream metadata
    // Store viewer statistics
    // Handle VoD records
}

• MongoDB - Production deployments
• MapDB - Development/testing
• Redis - Cluster mode metadata

• Broadcast information (stream ID, status, quality)
• Encoder settings
• Stream statistics
• Viewer counts
• VoD metadata
• Subscriber/token information

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7. Storage Client

• Amazon S3
• Azure Blob Storage
• Google Cloud Storage
• S3-compatible (MinIO, DigitalOcean Spaces)

• Upload HLS segments
• Upload MP4 recordings
• Upload preview images
• Delete on completion
• Manage storage classes

private boolean s3RecordingEnabled;
private String s3AccessKey;
private String s3SecretKey;
private String s3RegionName;
private String s3BucketName;
private String s3Endpoint;

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Streaming Pipeline

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Ingest to Delivery Flow

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Packet Flow Detail

1. Receive (AppSettings.java:1001-1003)
   • Protocol-specific adaptor accepts connection
   • Authenticates publisher
   • Extracts codec parameters
2. Process (Muxer.java:918)
   public synchronized boolean addStream(AVCodecParameters codecParameters, 
                                         AVRational timebase, int streamIndex)
   
   • Initialize streams in all muxers
   • Configure bitstream filters
   • Setup time base mapping
3. Encode (if ABR enabled)
   • Decode source stream
   • Encode to multiple bitrates
   • Apply encoder-specific parameters
4. Mux (Muxer.java:1204)
   public synchronized void writePacket(AVPacket pkt, AVRational inputTimebase, 
                                        AVRational outputTimebase, int codecType)
   
   • Convert timestamps
   • Apply bitstream filters
   • Write to container format
5. Deliver
   • HLS: Upload segments to storage
   • WebRTC: Forward via SRTP
   • Recording: Write to local/remote file

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Cluster Architecture

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Cluster Components

• Accept publisher connections
• Perform transcoding
• Generate HLS/DASH
• Upload to shared storage

• Serve viewers
• Pull streams from origins
• Cache segments locally
• Reduce origin load

private String clusterCommunicationKey;

• Synchronized stream metadata
• Cluster node status
• Viewer distribution

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Performance Considerations

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Resource Usage

• CPU: 5-10%
• RAM: 50-100 MB
• Bandwidth: Source bitrate × viewer count

• CPU: 50-150% (software) or 10-20% (hardware)
• RAM: 200-500 MB
• Bandwidth: Sum of all rendition bitrates × viewer count

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Optimization Strategies

encoderName=h264_nvenc
encoderSelectionPreference=gpu_and_cpu

encoderSettingsString=[
  {"height":720,"videoBitrate":1500000,"audioBitrate":96000},
  {"height":480,"videoBitrate":800000,"audioBitrate":64000}
]

encoderSettingsString=

hlsTime=2
hlsListSize=5
deleteHLSFilesOnEnded=true

clusterCommunicationKey=secretKey

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Monitoring & Debugging

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Key Metrics

• CPU and RAM usage
• Network throughput
• Active stream count
• Encoder queue depth

• Bitrate (video/audio)
• Frame rate
• Packet loss
• Viewer count
• Encoding speed

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REST API Monitoring

# Get server stats
curl https://your-server:5443/AppName/rest/v2/server-info

# Get broadcast info
curl https://your-server:5443/AppName/rest/v2/broadcasts/{streamId}

# Get viewer stats
curl https://your-server:5443/AppName/rest/v2/broadcasts/{streamId}/stats

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Logging

log4j.logger.io.antmedia.muxer=DEBUG
log4j.logger.io.antmedia.webrtc=DEBUG
log4j.logger.io.antmedia.enterprise=INFO

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Security Architecture

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Stream Security

private boolean publishTokenControlEnabled;
private boolean playTokenControlEnabled;

private boolean publishJwtControlEnabled;
private boolean playJwtControlEnabled;
private String jwtSecretKey;

private String allowedPublisherCIDR;
private String remoteAllowedCIDR;

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Transport Security

• WebRTC: DTLS/SRTP encryption (built-in)
• HTTPS: SSL/TLS for HLS/DASH delivery
• RTMPS: TLS encryption for RTMP
• SRT: Built-in AES encryption

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Next Steps