RTP (Real-time Transport Protocol): PHP parsing library

<?php
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

/**
 * The Real-time Transport Protocol (RTP) is a widely used network
 * protocol for transmitting audio or video. It usually works with the
 * RTP Control Protocol (RTCP). The transmission can be based on
 * Transmission Control Protocol (TCP) or User Datagram Protocol (UDP).
 */

namespace {
    class RtpPacket extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \Kaitai\Struct\Struct $_parent = null, \RtpPacket $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_version = $this->_io->readBitsIntBe(2);
            $this->_m_hasPadding = $this->_io->readBitsIntBe(1) != 0;
            $this->_m_hasExtension = $this->_io->readBitsIntBe(1) != 0;
            $this->_m_csrcCount = $this->_io->readBitsIntBe(4);
            $this->_m_marker = $this->_io->readBitsIntBe(1) != 0;
            $this->_m_payloadType = $this->_io->readBitsIntBe(7);
            $this->_io->alignToByte();
            $this->_m_sequenceNumber = $this->_io->readU2be();
            $this->_m_timestamp = $this->_io->readU4be();
            $this->_m_ssrc = $this->_io->readU4be();
            if ($this->hasExtension()) {
                $this->_m_headerExtension = new \RtpPacket\HeaderExtention($this->_io, $this, $this->_root);
            }
            $this->_m_data = $this->_io->readBytes((($this->_io()->size() - $this->_io()->pos()) - $this->lenPadding()));
            $this->_m_padding = $this->_io->readBytes($this->lenPadding());
        }
        protected $_m_lenPaddingIfExists;

        /**
         * If padding bit is enabled, last byte of data contains number of
         * bytes appended to the payload as padding.
         */
        public function lenPaddingIfExists() {
            if ($this->_m_lenPaddingIfExists !== null)
                return $this->_m_lenPaddingIfExists;
            if ($this->hasPadding()) {
                $_pos = $this->_io->pos();
                $this->_io->seek(($this->_io()->size() - 1));
                $this->_m_lenPaddingIfExists = $this->_io->readU1();
                $this->_io->seek($_pos);
            }
            return $this->_m_lenPaddingIfExists;
        }
        protected $_m_lenPadding;

        /**
         * Always returns number of padding bytes to in the payload.
         */
        public function lenPadding() {
            if ($this->_m_lenPadding !== null)
                return $this->_m_lenPadding;
            $this->_m_lenPadding = ($this->hasPadding() ? $this->lenPaddingIfExists() : 0);
            return $this->_m_lenPadding;
        }
        protected $_m_version;
        protected $_m_hasPadding;
        protected $_m_hasExtension;
        protected $_m_csrcCount;
        protected $_m_marker;
        protected $_m_payloadType;
        protected $_m_sequenceNumber;
        protected $_m_timestamp;
        protected $_m_ssrc;
        protected $_m_headerExtension;
        protected $_m_data;
        protected $_m_padding;
        public function version() { return $this->_m_version; }
        public function hasPadding() { return $this->_m_hasPadding; }
        public function hasExtension() { return $this->_m_hasExtension; }
        public function csrcCount() { return $this->_m_csrcCount; }
        public function marker() { return $this->_m_marker; }
        public function payloadType() { return $this->_m_payloadType; }
        public function sequenceNumber() { return $this->_m_sequenceNumber; }
        public function timestamp() { return $this->_m_timestamp; }
        public function ssrc() { return $this->_m_ssrc; }
        public function headerExtension() { return $this->_m_headerExtension; }

        /**
         * Payload without padding.
         */
        public function data() { return $this->_m_data; }
        public function padding() { return $this->_m_padding; }
    }
}

namespace RtpPacket {
    class HeaderExtention extends \Kaitai\Struct\Struct {
        public function __construct(\Kaitai\Struct\Stream $_io, \RtpPacket $_parent = null, \RtpPacket $_root = null) {
            parent::__construct($_io, $_parent, $_root);
            $this->_read();
        }

        private function _read() {
            $this->_m_id = $this->_io->readU2be();
            $this->_m_length = $this->_io->readU2be();
        }
        protected $_m_id;
        protected $_m_length;
        public function id() { return $this->_m_id; }
        public function length() { return $this->_m_length; }
    }
}

namespace RtpPacket {
    class PayloadTypeEnum {
        const PCMU = 0;
        const RESERVED1 = 1;
        const RESERVED2 = 2;
        const GSM = 3;
        const G723 = 4;
        const DVI4_1 = 5;
        const DVI4_2 = 6;
        const LPC = 7;
        const PCMA = 8;
        const G722 = 9;
        const L16_1 = 10;
        const L16_2 = 11;
        const QCELP = 12;
        const CN = 13;
        const MPA = 14;
        const G728 = 15;
        const DVI4_3 = 16;
        const DVI4_4 = 17;
        const G729 = 18;
        const RESERVED19 = 19;
        const UNASSIGNED20 = 20;
        const UNASSIGNED21 = 21;
        const UNASSIGNED22 = 22;
        const UNASSIGNED23 = 23;
        const UNASSIGNED24 = 24;
        const CELB = 25;
        const JPEG = 26;
        const UNASSIGNED27 = 27;
        const NV = 28;
        const UNASSIGNED29 = 29;
        const UNASSIGNED30 = 30;
        const H261 = 31;
        const MPV = 32;
        const MP2T = 33;
        const H263 = 34;
        const MPEG_PS = 96;
    }
}