/getid3/module.audio-video.swf.php

<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// 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 {
	var $ReturnAllTagData = false;
	
	function Analyze() {
		$info = &$this->getid3->info;
		
		$info ['fileformat'] = 'swf';
		$info ['video'] ['dataformat'] = 'swf';
		
		// http://www.openswf.org/spec/SWFfileformat.html
		

		fseek ( $this->getid3->fp, $info ['avdataoffset'], SEEK_SET );
		
		$SWFfileData = fread ( $this->getid3->fp, $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 :
				$info ['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 )) != false) {
				$SWFfileData = $SWFHead . $decompressed;
			} else {
				$info ['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;
	}

}