SDP Parser and Serializer for PHP

RFC 2327, RFC 4566 and RFC 8866 compliant SDP parsing/serialization library for PHP.

Quickstart

Session Description Parsing

Once installed, you can parse SDP session description right away as follows:

<?php

use RTCKit\SDP\Parser;

require_once __DIR__ . '/vendor/autoload.php';

$parser = new Parser;
$sdp = <<<SDP
v=0
o=- 20518 0 IN IP4 192.168.0.1
s=VoIP Call
c=IN IP4 192.168.0.1
t=0 0
m=audio 5004 RTP/AVP 0 8 18
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=ptime:20
SDP;

$session = $parser->parse($sdp);
echo json_encode($session, JSON_PRETTY_PRINT);

The $session variable (a stdClass object) will now be populated with the parsed SDP session description. Here's the output of the above example:

{
    "version": 0,
    "origin": {
        "username": "-",
        "sessionId": 20518,
        "sessionVersion": 0,
        "netType": "IN",
        "ipVer": 4,
        "address": "192.168.0.1"
    },
    "name": "VoIP Call",
    "connection": {
        "version": 4,
        "ip": "192.168.0.1"
    },
    "timing": {
        "start": 0,
        "stop": 0
    },
    "media": [
        {
            "rtp": [
                {
                    "payload": 0,
                    "codec": "PCMU",
                    "rate": 8000
                },
                {
                    "payload": 8,
                    "codec": "PCMA",
                    "rate": 8000
                },
                {
                    "payload": 18,
                    "codec": "G729",
                    "rate": 8000
                }
            ],
            "fmtp": [],
            "type": "audio",
            "port": 5004,
            "protocol": "RTP\/AVP",
            "payloads": "0 8 18",
            "ptime": 20
        }
    ]
}

Session Description Serialization

Serializing is the opposite action of parsing:

<?php

use RTCKit\SDP\Serializer;

require_once __DIR__ . '/vendor/autoload.php';

$session = new stdClass;

$session->version = 0;
$session->origin = new stdClass;
$session->origin->username = '-';
$session->origin->sessionId = 20518;
$session->origin->sessionVersion = 0;
$session->origin->netType = 'IN';
$session->origin->ipVer = 4;
$session->origin->address = '192.168.0.1';
$session->name = 'VoIP Call';
$session->connection = new stdClass;
$session->connection->version = 4;
$session->connection->ip = '192.168.0.1';
$session->timing = new stdClass;
$session->timing->start = 0;
$session->timing->stop = 0;
$session->media = [
    new stdClass
];
$session->media[0]->rtp = [
    new stdClass,
    new stdClass,
    new stdClass
];
$session->media[0]->rtp[0]->payload = 0;
$session->media[0]->rtp[0]->codec = 'PCMU';
$session->media[0]->rtp[0]->rate = 8000;
$session->media[0]->rtp[1]->payload = 8;
$session->media[0]->rtp[1]->codec = 'PCMA';
$session->media[0]->rtp[1]->rate = 8000;
$session->media[0]->rtp[2]->payload = 18;
$session->media[0]->rtp[2]->codec = 'G729';
$session->media[0]->rtp[2]->rate = 8000;
$session->media[0]->fmtp = [];
$session->media[0]->type = 'audio';
$session->media[0]->port = 5004;
$session->media[0]->protocol = 'RTP/AVP';
$session->media[0]->payloads = '0 8 18';
$session->media[0]->ptime = 20;

$serializer = new Serializer;
$sdp = $serializer->serialize($session);
echo $sdp;

The $sdp variable will now contain the serialized SDP session description:

v=0
o=- 20518 0 IN IP4 192.168.0.1
s=VoIP Call
c=IN IP4 192.168.0.1
t=0 0
m=audio 5004 RTP/AVP 0 8 18
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:18 G729/8000
a=ptime:20

Requirements

RTCKit\SDP is compatible with PHP 8.1+ and has no external library and extension dependencies.

Installation

You can add the library as project dependency using Composer:

composer require rtckit/sdp

If you only need the library during development, for instance when used in your test suite, then you should add it as a development-only dependency:

composer require --dev rtckit/sdp

Tests

To run the test suite, clone this repository and then install dependencies via Composer:

composer install

Then, go to the project root and run:

php -d memory_limit=-1 ./vendor/bin/phpunit -c ./etc/phpunit.xml.dist

Static Analysis

In order to ensure high code quality, RTCKit\SDP uses PHPStan and Psalm:

php -d memory_limit=-1 ./vendor/bin/phpstan analyse -c ./etc/phpstan.neon -n -vvv --ansi --level=max src
php -d memory_limit=-1 ./vendor/bin/psalm --config=./etc/psalm.xml

License

MIT, see LICENSE file.

Acknowledgments

• sdp-transform - SDP parser and serializer for JavaScript, main source of inspiration for this library
• RFC 2327 - SDP: Session Description Protocol (April 1998)
• RFC 4566 - SDP: Session Description Protocol (July 2006)
• RFC 8866 - SDP: Session Description Protocol (January 2021)

Contributing

Bug reports (and small patches) can be submitted via the issue tracker. Forking the repository and submitting a Pull Request is preferred for substantial patches.