GB/T 28181 SDP Parser

Inspect origin, connection, media, payload and attribute lines in SDP.

Protocol scope and method

The tool reads common SDP line prefixes and reports media and connection values without establishing a session.

SDP line = one-letter type + "=" + value.

Diagnostic scenario

Extract the SDP body from a redacted INVITE or 200 response after verifying Content-Length. Compare connection address, media port, transport, payload mappings, SSRC-related attributes and direction with the actual RTP or TCP media flow.

How to interpret the result

SDP describes a media offer or answer, not proof that packets reached the advertised endpoint. Session-level and media-level connection lines have scope, dynamic payload types require rtpmap, and NAT or platform relays can change the observed network path.

Input reference

SDP text
Example default: Sample input included

Common mistakes

  • Using an unredacted production capture with vehicle, credential or network identifiers.
  • Reading only the session-level connection address when media overrides it.
  • Treating a successfully parsed sample as standards compliance or interoperability proof.

Before using the result

  1. Confirm the protocol edition, transport framing and vendor profile before interpreting fields.
  2. Compare negotiated address, port and payload mapping with packet capture.
  3. Keep a redacted known-good and known-bad sample as a regression pair.

Questions to check during diagnosis

Does the GB/T 28181 SDP Parser leave my browser?

No application upload is used. Avoid putting sensitive production data in shareable URLs.

Is this a standards compliance test?

No. Confirm the edition and vendor profile with licensed documents and your target platform.

Offline diagnostic aid. Verify fields, version and vendor extensions before production use.

Detailed engineering guide

GB/T 28181 diagnostics: SIP dialogs, SDP media and Catalog XML

A syntactically valid message can still fail at transaction, dialog, profile or media layers. This guide correlates those layers without exposing credentials or real endpoints.

Read the guide