RTP Packet Decoder/Encoder

Common errors

• ModuleNotFoundError: No module named 'rtp'

  cause The 'rtp' library is not installed in the current Python environment.
  fix Run `pip install rtp` to install the library.

• AttributeError: module 'rtp' has no attribute 'RTP'

  cause Attempting to access the `RTP` class directly after a simple `import rtp` instead of `from rtp import RTP`, or a conflict with another library named 'rtp' (less likely for this specific library).
  fix Use `from rtp import RTP` to directly import the class, or ensure you are not shadowing another module.

• TypeError: 'bytes' object cannot be interpreted as an integer

  cause This error or similar `TypeError` can occur when passing malformed byte data to `RTP.fromBytearray()`, or when attempting to use an incorrect type for a parameter during packet creation.
  fix Ensure that the byte array passed to `fromBytearray()` represents a valid RTP packet, and that all parameters for `RTP()` constructor are of the expected types and formats.

Warnings

• gotcha This library explicitly handles only RTP packet encoding/decoding and does NOT provide any network functionality (like sending over UDP) or specific payload handling. Users need to implement or integrate with other libraries for these aspects.
  Fix: Ensure you have separate components for network transport (e.g., `socket` module) and specific payload type encoding/decoding (e.g., `rtpPayload-ttml`).
• breaking As a library in early development (version 0.0.4), expect potential breaking changes in minor versions (0.x.x) as the API matures. Always review release notes when upgrading.
  Fix: Consult the GitHub repository's release notes or changelog for specific breaking changes before upgrading. Pin exact versions in your `requirements.txt`.
• gotcha The quickstart examples and common usage patterns require helper functions (e.g., `getExtStartBits`, `getExtBody`, `getCSRCList`, `getNextPayload`) that are not part of the `rtp` library itself. Users must provide these based on their specific RTP implementation needs.
  Fix: Implement the necessary helper functions to generate extension headers, CSRC lists, and actual payload data according to your RTP stream specifications.

Install

• pip install rtp Install latest version

Imports

• RTP

  from rtp import RTP

• Extension

  from rtp import Extension

• PayloadType

  from rtp import PayloadType

Quickstart

This quickstart demonstrates how to create and manipulate RTP packets. It includes examples for both encoding and decoding. Note that placeholder functions (e.g., `getExtStartBits`, `getNextPayload`) are used as the `rtp` library focuses solely on RTP packet structure, not on network transmission or specific payload content.

from rtp import RTP, Extension, PayloadType
from copy import deepcopy

# Placeholder functions for demonstration, as 'rtp' is payload-agnostic
def getExtStartBits(): return b'\x10\x00'
def getExtBody(): return b'\x01\x02\x03\x04'
def getCSRCList(): return [12345]
def getNextPayload(): return b'\xDE\xAD\xBE\xEF'
def transmit(rtp_packet): print(f"Transmitting: {rtp_packet.toBytearray().hex()}")
def getNextPacket(): return bytes.fromhex('80e000000000000000000000100001020304deadbeef')
def MyPayloadDecoder(payload_bytes): return f"Decoded payload: {payload_bytes.hex()}"
def render(decoded_data): print(f"Rendering: {decoded_data}")

# Encoding example
baseRTP = RTP(
    marker=True,
    payloadType=PayloadType.DYNAMIC_96, # Using a common dynamic payload type for example
    extension=Extension(
        startBits=getExtStartBits(),
        headerExtension=getExtBody()
    ),
    csrcList=getCSRCList()
)

# Initial packet
thisRTPBitstream = baseRTP.toBytearray()
print(f"Initial RTP Packet (hex): {thisRTPBitstream.hex()}")

# Example of sending subsequent packets (simplified loop)
nextRTP = deepcopy(baseRTP)
nextRTP.sequenceNumber += 1
nextRTP.timestamp += 160 # Example increment for timestamp
nextRTP.payload = getNextPayload()
transmit(nextRTP)

# Decoding example
decoded_rtp_packet = RTP().fromBytearray(getNextPacket())
decodedPayload = MyPayloadDecoder(decoded_rtp_packet.payload)
render(decodedPayload)

print(f"Decoded Sequence Number: {decoded_rtp_packet.sequenceNumber}")
print(f"Decoded Timestamp: {decoded_rtp_packet.timestamp}")