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Pion Interceptor provides a comprehensive set of built-in interceptors for common WebRTC operations. These interceptors can be composed together to add functionality to RTP/RTCP streams.

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Available Interceptors

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Congestion Control

NACK

Request and respond to packet retransmissions

GCC

Google Congestion Control for bandwidth estimation

TWCC

Transport-wide congestion control feedback

RFC 8888

RTP Congestion Control Feedback

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Quality and Reliability

FlexFEC

Forward error correction for packet recovery

Jitter Buffer

Smooth packet arrival and handle network jitter

Pacing

Control packet sending rate

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Reporting and Monitoring

Reports

Generate sender and receiver reports

Statistics

Collect detailed stream statistics

Interval PLI

Request keyframes at regular intervals

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Debugging

Packet Dump

Dump RTP/RTCP packets for debugging and analysis

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How Interceptors Work

Interceptors sit in the RTP/RTCP processing pipeline and can:
  • Read incoming RTP/RTCP packets
  • Write outgoing RTP/RTCP packets
  • Modify packet contents
  • Generate new RTCP feedback
  • Buffer packets for reordering or retransmission
Interceptors are bound to streams and peer connections, allowing fine-grained control over packet processing.

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Creating an Interceptor Chain

Multiple interceptors can be composed together: 
import (
    "github.com/pion/interceptor"
    "github.com/pion/interceptor/pkg/gcc"
    "github.com/pion/interceptor/pkg/nack"
    "github.com/pion/interceptor/pkg/report"
)

// Create an interceptor registry
m := &interceptor.Registry{}

// Register multiple interceptors
interceptor.RegisterDefaultInterceptors(m, &mediaEngine)

// Add NACK support
generatorFactory, _ := nack.NewGeneratorInterceptor()
m.Add(generatorFactory)

responderFactory, _ := nack.NewResponderInterceptor()
m.Add(responderFactory)

// Add sender/receiver reports
senderFactory, _ := report.NewSenderInterceptor()
m.Add(senderFactory)

receiverFactory, _ := report.NewReceiverInterceptor()
m.Add(receiverFactory)

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Configuration Options

Most interceptors support configuration through functional options: 
// Configure NACK generator with custom settings
generatorFactory, _ := nack.NewGeneratorInterceptor(
    nack.GeneratorSize(1024),
    nack.GeneratorInterval(100 * time.Millisecond),
    nack.GeneratorMaxNacksPerPacket(3),
)
See individual interceptor pages for specific configuration options and usage examples.

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Best Practices

  1. Order Matters: The order in which interceptors are added affects the processing pipeline
  2. Resource Management: Always close interceptors when done to free resources
  3. Logging: Use logger factories for debugging and monitoring
  4. Testing: Test interceptor chains with your specific use case

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Next Steps

Explore the individual interceptor documentation to learn more about each component and how to configure them for your use case.

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