module.audio-video.swf.php

Go to the documentation of this file.

<?php
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
//          also https://github.com/JamesHeinrich/getID3       //
// See readme.txt for more details                             //
//                                                             //
// module.audio-video.swf.php                                  //
// module for analyzing Shockwave Flash files                  //
// dependencies: NONE                                          //
//                                                            ///


class getid3_swf extends getid3_handler
{
        public $ReturnAllTagData = false;

        public function Analyze() {
                $info = &$this->getid3->info;

                $info['fileformat']          = 'swf';
                $info['video']['dataformat'] = 'swf';

                // http://www.openswf.org/spec/SWFfileformat.html

                $this->fseek($info['avdataoffset']);

                $SWFfileData = $this->fread($info['avdataend'] - $info['avdataoffset']); // 8 + 2 + 2 + max(9) bytes NOT including Frame_Size RECT data

                $info['swf']['header']['signature']  = substr($SWFfileData, 0, 3);
                switch ($info['swf']['header']['signature']) {
                        case 'FWS':
                                $info['swf']['header']['compressed'] = false;
                                break;

                        case 'CWS':
                                $info['swf']['header']['compressed'] = true;
                                break;

                        default:
                                $this->error('Expecting "FWS" or "CWS" at offset '.$info['avdataoffset'].', found "'.getid3_lib::PrintHexBytes($info['swf']['header']['signature']).'"');
                                unset($info['swf']);
                                unset($info['fileformat']);
                                return false;
                                break;
                }
                $info['swf']['header']['version'] = getid3_lib::LittleEndian2Int(substr($SWFfileData, 3, 1));
                $info['swf']['header']['length']  = getid3_lib::LittleEndian2Int(substr($SWFfileData, 4, 4));

                if ($info['swf']['header']['compressed']) {
                        $SWFHead     = substr($SWFfileData, 0, 8);
                        $SWFfileData = substr($SWFfileData, 8);
                        if ($decompressed = @gzuncompress($SWFfileData)) {
                                $SWFfileData = $SWFHead.$decompressed;
                        } else {
                                $this->error('Error decompressing compressed SWF data ('.strlen($SWFfileData).' bytes compressed, should be '.($info['swf']['header']['length'] - 8).' bytes uncompressed)');
                                return false;
                        }
                }

                $FrameSizeBitsPerValue = (ord(substr($SWFfileData, 8, 1)) & 0xF8) >> 3;
                $FrameSizeDataLength   = ceil((5 + (4 * $FrameSizeBitsPerValue)) / 8);
                $FrameSizeDataString   = str_pad(decbin(ord(substr($SWFfileData, 8, 1)) & 0x07), 3, '0', STR_PAD_LEFT);
                for ($i = 1; $i < $FrameSizeDataLength; $i++) {
                        $FrameSizeDataString .= str_pad(decbin(ord(substr($SWFfileData, 8 + $i, 1))), 8, '0', STR_PAD_LEFT);
                }
                list($X1, $X2, $Y1, $Y2) = explode("\n", wordwrap($FrameSizeDataString, $FrameSizeBitsPerValue, "\n", 1));
                $info['swf']['header']['frame_width']  = getid3_lib::Bin2Dec($X2);
                $info['swf']['header']['frame_height'] = getid3_lib::Bin2Dec($Y2);

                // http://www-lehre.informatik.uni-osnabrueck.de/~fbstark/diplom/docs/swf/Flash_Uncovered.htm
                // Next in the header is the frame rate, which is kind of weird.
                // It is supposed to be stored as a 16bit integer, but the first byte
                // (or last depending on how you look at it) is completely ignored.
                // Example: 0x000C  ->  0x0C  ->  12     So the frame rate is 12 fps.

                // Byte at (8 + $FrameSizeDataLength) is always zero and ignored
                $info['swf']['header']['frame_rate']  = getid3_lib::LittleEndian2Int(substr($SWFfileData,  9 + $FrameSizeDataLength, 1));
                $info['swf']['header']['frame_count'] = getid3_lib::LittleEndian2Int(substr($SWFfileData, 10 + $FrameSizeDataLength, 2));

                $info['video']['frame_rate']         = $info['swf']['header']['frame_rate'];
                $info['video']['resolution_x']       = intval(round($info['swf']['header']['frame_width']  / 20));
                $info['video']['resolution_y']       = intval(round($info['swf']['header']['frame_height'] / 20));
                $info['video']['pixel_aspect_ratio'] = (float) 1;

                if (($info['swf']['header']['frame_count'] > 0) && ($info['swf']['header']['frame_rate'] > 0)) {
                        $info['playtime_seconds'] = $info['swf']['header']['frame_count'] / $info['swf']['header']['frame_rate'];
                }
//echo __LINE__.'='.number_format(microtime(true) - $start_time, 3).'<br>';


                // SWF tags

                $CurrentOffset = 12 + $FrameSizeDataLength;
                $SWFdataLength = strlen($SWFfileData);

                while ($CurrentOffset < $SWFdataLength) {
//echo __LINE__.'='.number_format(microtime(true) - $start_time, 3).'<br>';

                        $TagIDTagLength = getid3_lib::LittleEndian2Int(substr($SWFfileData, $CurrentOffset, 2));
                        $TagID     = ($TagIDTagLength & 0xFFFC) >> 6;
                        $TagLength = ($TagIDTagLength & 0x003F);
                        $CurrentOffset += 2;
                        if ($TagLength == 0x3F) {
                                $TagLength = getid3_lib::LittleEndian2Int(substr($SWFfileData, $CurrentOffset, 4));
                                $CurrentOffset += 4;
                        }

                        unset($TagData);
                        $TagData['offset'] = $CurrentOffset;
                        $TagData['size']   = $TagLength;
                        $TagData['id']     = $TagID;
                        $TagData['data']   = substr($SWFfileData, $CurrentOffset, $TagLength);
                        switch ($TagID) {
                                case 0: // end of movie
                                        break 2;

                                case 9: // Set background color
                                        //$info['swf']['tags'][] = $TagData;
                                        $info['swf']['bgcolor'] = strtoupper(str_pad(dechex(getid3_lib::BigEndian2Int($TagData['data'])), 6, '0', STR_PAD_LEFT));
                                        break;

                                default:
                                        if ($this->ReturnAllTagData) {
                                                $info['swf']['tags'][] = $TagData;
                                        }
                                        break;
                        }

                        $CurrentOffset += $TagLength;
                }

                return true;
        }

}