module.audio.flac.php

一个用PHP编写的

<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <[e-mail]>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio.flac.php                                       //
// module for analyzing FLAC and OggFLAC audio files           //
// dependencies: module.audio.ogg.php                          //
//                                                            ///
/////////////////////////////////////////////////////////////////


getid3_lib::IncludeDependency(GETID3_INCLUDEPATH.'module.audio.ogg.php', __FILE__, true);

class getid3_flac
{

	function getid3_flac(&$fd, &$ThisFileInfo) {
		// http://flac.sourceforge.net/format.html

		fseek($fd, $ThisFileInfo['avdataoffset'], SEEK_SET);
		$StreamMarker = fread($fd, 4);
		if ($StreamMarker != 'fLaC') {
			$ThisFileInfo['error'][] = 'Expecting "fLaC" at offset '.$ThisFileInfo['avdataoffset'].', found "'.$StreamMarker.'"';
			return false;
		}
		$ThisFileInfo['fileformat']            = 'flac';
		$ThisFileInfo['audio']['dataformat']   = 'flac';
		$ThisFileInfo['audio']['bitrate_mode'] = 'vbr';
		$ThisFileInfo['audio']['lossless']     = true;

		return getid3_flac::FLACparseMETAdata($fd, $ThisFileInfo);
	}


	function FLACparseMETAdata(&$fd, &$ThisFileInfo) {

		do {
			$METAdataBlockOffset          = ftell($fd);
			$METAdataBlockHeader          = fread($fd, 4);
			$METAdataLastBlockFlag        = (bool) (getid3_lib::BigEndian2Int(substr($METAdataBlockHeader, 0, 1)) & 0x80);
			$METAdataBlockType            = getid3_lib::BigEndian2Int(substr($METAdataBlockHeader, 0, 1)) & 0x7F;
			$METAdataBlockLength          = getid3_lib::BigEndian2Int(substr($METAdataBlockHeader, 1, 3));
			$METAdataBlockTypeText        = getid3_flac::FLACmetaBlockTypeLookup($METAdataBlockType);

			if ($METAdataBlockLength < 0) {
				$ThisFileInfo['error'][] = 'corrupt or invalid METADATA_BLOCK_HEADER.BLOCK_TYPE ('.$METAdataBlockType.') at offset '.$METAdataBlockOffset;
				break;
			}

			$ThisFileInfo['flac'][$METAdataBlockTypeText]['raw'] = array();
			$ThisFileInfo_flac_METAdataBlockTypeText_raw = &$ThisFileInfo['flac'][$METAdataBlockTypeText]['raw'];

			$ThisFileInfo_flac_METAdataBlockTypeText_raw['offset']          = $METAdataBlockOffset;
			$ThisFileInfo_flac_METAdataBlockTypeText_raw['last_meta_block'] = $METAdataLastBlockFlag;
			$ThisFileInfo_flac_METAdataBlockTypeText_raw['block_type']      = $METAdataBlockType;
			$ThisFileInfo_flac_METAdataBlockTypeText_raw['block_type_text'] = $METAdataBlockTypeText;
			$ThisFileInfo_flac_METAdataBlockTypeText_raw['block_length']    = $METAdataBlockLength;
			$ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data']      = @fread($fd, $METAdataBlockLength);
			$ThisFileInfo['avdataoffset'] = ftell($fd);

			switch ($METAdataBlockTypeText) {

				case 'STREAMINFO':
					if (!getid3_flac::FLACparseSTREAMINFO($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
						return false;
					}
					break;

				case 'PADDING':
					// ignore
					break;

				case 'APPLICATION':
					if (!getid3_flac::FLACparseAPPLICATION($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
						return false;
					}
					break;

				case 'SEEKTABLE':
					if (!getid3_flac::FLACparseSEEKTABLE($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
						return false;
					}
					break;

				case 'VORBIS_COMMENT':
					$OldOffset = ftell($fd);
					fseek($fd, 0 - $METAdataBlockLength, SEEK_CUR);
					getid3_ogg::ParseVorbisCommentsFilepointer($fd, $ThisFileInfo);
					fseek($fd, $OldOffset, SEEK_SET);
					break;

				case 'CUESHEET':
					if (!getid3_flac::FLACparseCUESHEET($ThisFileInfo_flac_METAdataBlockTypeText_raw['block_data'], $ThisFileInfo)) {
						return false;
					}
					break;

				default:
					$ThisFileInfo['warning'][] = 'Unhandled METADATA_BLOCK_HEADER.BLOCK_TYPE ('.$METAdataBlockType.') at offset '.$METAdataBlockOffset;
					break;
			}

		} while ($METAdataLastBlockFlag === false);


		if (isset($ThisFileInfo['flac']['STREAMINFO'])) {
			$ThisFileInfo['flac']['compressed_audio_bytes']   = $ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset'];
			$ThisFileInfo['flac']['uncompressed_audio_bytes'] = $ThisFileInfo['flac']['STREAMINFO']['samples_stream'] * $ThisFileInfo['flac']['STREAMINFO']['channels'] * ($ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'] / 8);
			if ($ThisFileInfo['flac']['uncompressed_audio_bytes'] == 0) {
				$ThisFileInfo['error'][] = 'Corrupt FLAC file: uncompressed_audio_bytes == zero';
				return false;
			}
			$ThisFileInfo['flac']['compression_ratio']        = $ThisFileInfo['flac']['compressed_audio_bytes'] / $ThisFileInfo['flac']['uncompressed_audio_bytes'];
		}

		// set md5_data_source - built into flac 0.5+
		if (isset($ThisFileInfo['flac']['STREAMINFO']['audio_signature'])) {

			if ($ThisFileInfo['flac']['STREAMINFO']['audio_signature'] === str_repeat("\x00", 16)) {

				$ThisFileInfo['warning'][] = 'FLAC STREAMINFO.audio_signature is null (known issue with libOggFLAC)';

			} else {

				$ThisFileInfo['md5_data_source'] = '';
				$md5 = $ThisFileInfo['flac']['STREAMINFO']['audio_signature'];
				for ($i = 0; $i < strlen($md5); $i++) {
					$ThisFileInfo['md5_data_source'] .= str_pad(dechex(ord($md5{$i})), 2, '00', STR_PAD_LEFT);
				}
				if (!preg_match('/^[0-9a-f]{32}$/', $ThisFileInfo['md5_data_source'])) {
					unset($ThisFileInfo['md5_data_source']);
				}

			}

		}

		$ThisFileInfo['audio']['bits_per_sample'] = $ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'];
		if ($ThisFileInfo['audio']['bits_per_sample'] == 8) {
			// special case
			// must invert sign bit on all data bytes before MD5'ing to match FLAC's calculated value
			// MD5sum calculates on unsigned bytes, but FLAC calculated MD5 on 8-bit audio data as signed
			$ThisFileInfo['warning'][] = 'FLAC calculates MD5 data strangely on 8-bit audio, so the stored md5_data_source value will not match the decoded WAV file';
		}
		if (!empty($ThisFileInfo['ogg']['vendor'])) {
			$ThisFileInfo['audio']['encoder'] = $ThisFileInfo['ogg']['vendor'];
		}

		return true;
	}

	function FLACmetaBlockTypeLookup($blocktype) {
		static $FLACmetaBlockTypeLookup = array();
		if (empty($FLACmetaBlockTypeLookup)) {
			$FLACmetaBlockTypeLookup[0] = 'STREAMINFO';
			$FLACmetaBlockTypeLookup[1] = 'PADDING';
			$FLACmetaBlockTypeLookup[2] = 'APPLICATION';
			$FLACmetaBlockTypeLookup[3] = 'SEEKTABLE';
			$FLACmetaBlockTypeLookup[4] = 'VORBIS_COMMENT';
			$FLACmetaBlockTypeLookup[5] = 'CUESHEET';
		}
		return (isset($FLACmetaBlockTypeLookup[$blocktype]) ? $FLACmetaBlockTypeLookup[$blocktype] : 'reserved');
	}

	function FLACapplicationIDLookup($applicationid) {
		static $FLACapplicationIDLookup = array();
		if (empty($FLACapplicationIDLookup)) {
			// http://flac.sourceforge.net/id.html
			$FLACapplicationIDLookup[0x46746F6C] = 'flac-tools';      // 'Ftol'
			$FLACapplicationIDLookup[0x46746F6C] = 'Sound Font FLAC'; // 'SFFL'
		}
		return (isset($FLACapplicationIDLookup[$applicationid]) ? $FLACapplicationIDLookup[$applicationid] : 'reserved');
	}

	function FLACparseSTREAMINFO($METAdataBlockData, &$ThisFileInfo) {
		$offset = 0;
		$ThisFileInfo['flac']['STREAMINFO']['min_block_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 2));
		$offset += 2;
		$ThisFileInfo['flac']['STREAMINFO']['max_block_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 2));
		$offset += 2;
		$ThisFileInfo['flac']['STREAMINFO']['min_frame_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 3));
		$offset += 3;
		$ThisFileInfo['flac']['STREAMINFO']['max_frame_size']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 3));
		$offset += 3;

		$SampleRateChannelsSampleBitsStreamSamples             = getid3_lib::BigEndian2Bin(substr($METAdataBlockData, $offset, 8));
		$ThisFileInfo['flac']['STREAMINFO']['sample_rate']     = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples,  0, 20));
		$ThisFileInfo['flac']['STREAMINFO']['channels']        = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples, 20,  3)) + 1;
		$ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'] = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples, 23,  5)) + 1;
		$ThisFileInfo['flac']['STREAMINFO']['samples_stream']  = getid3_lib::Bin2Dec(substr($SampleRateChannelsSampleBitsStreamSamples, 28, 36));
		$offset += 8;

		$ThisFileInfo['flac']['STREAMINFO']['audio_signature'] =               substr($METAdataBlockData, $offset, 16);
		$offset += 16;

		if (!empty($ThisFileInfo['flac']['STREAMINFO']['sample_rate'])) {

			$ThisFileInfo['audio']['bitrate_mode']     = 'vbr';
			$ThisFileInfo['audio']['sample_rate']      = $ThisFileInfo['flac']['STREAMINFO']['sample_rate'];
			$ThisFileInfo['audio']['channels']         = $ThisFileInfo['flac']['STREAMINFO']['channels'];
			$ThisFileInfo['audio']['bits_per_sample']  = $ThisFileInfo['flac']['STREAMINFO']['bits_per_sample'];
			$ThisFileInfo['playtime_seconds']          = $ThisFileInfo['flac']['STREAMINFO']['samples_stream'] / $ThisFileInfo['flac']['STREAMINFO']['sample_rate'];
			$ThisFileInfo['audio']['bitrate']          = (($ThisFileInfo['avdataend'] - $ThisFileInfo['avdataoffset']) * 8) / $ThisFileInfo['playtime_seconds'];

		} else {

			$ThisFileInfo['error'][] = 'Corrupt METAdata block: STREAMINFO';
			return false;

		}
		return true;
	}


	function FLACparseAPPLICATION($METAdataBlockData, &$ThisFileInfo) {
		$offset = 0;
		$ApplicationID = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 4));
		$offset += 4;
		$ThisFileInfo['flac']['APPLICATION'][$ApplicationID]['name'] = getid3_flac::FLACapplicationIDLookup($ApplicationID);
		$ThisFileInfo['flac']['APPLICATION'][$ApplicationID]['data'] = substr($METAdataBlockData, $offset);
		$offset = $METAdataBlockLength;

		return true;
	}


	function FLACparseSEEKTABLE($METAdataBlockData, &$ThisFileInfo) {
		$offset = 0;
		$METAdataBlockLength = strlen($METAdataBlockData);
		$placeholderpattern = str_repeat("\xFF", 8);
		while ($offset < $METAdataBlockLength) {
			$SampleNumberString = substr($METAdataBlockData, $offset, 8);
			$offset += 8;
			if ($SampleNumberString == $placeholderpattern) {

				// placeholder point
				@$ThisFileInfo['flac']['SEEKTABLE']['placeholders']++;
				$offset += 10;

			} else {

				$SampleNumber                                                = getid3_lib::BigEndian2Int($SampleNumberString);
				$ThisFileInfo['flac']['SEEKTABLE'][$SampleNumber]['offset']  = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
				$offset += 8;
				$ThisFileInfo['flac']['SEEKTABLE'][$SampleNumber]['samples'] = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 2));
				$offset += 2;

			}
		}
		return true;
	}

	function FLACparseCUESHEET($METAdataBlockData, &$ThisFileInfo) {
		$offset = 0;
		$ThisFileInfo['flac']['CUESHEET']['media_catalog_number'] =          trim(substr($METAdataBlockData, $offset, 128), "\0");
		$offset += 128;
		$ThisFileInfo['flac']['CUESHEET']['lead_in_samples']      = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
		$offset += 8;
		$ThisFileInfo['flac']['CUESHEET']['flags']['is_cd']       = (bool) (getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1)) & 0x80);
		$offset += 1;

		$offset += 258; // reserved

		$ThisFileInfo['flac']['CUESHEET']['number_tracks']        = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
		$offset += 1;

		for ($track = 0; $track < $ThisFileInfo['flac']['CUESHEET']['number_tracks']; $track++) {
			$TrackSampleOffset = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
			$offset += 8;
			$TrackNumber       = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
			$offset += 1;

			$ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['sample_offset']         = $TrackSampleOffset;

			$ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['isrc']                  =               substr($METAdataBlockData, $offset, 12);
			$offset += 12;

			$TrackFlagsRaw                                                                     = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
			$offset += 1;
			$ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['is_audio']     = (bool) ($TrackFlagsRaw & 0x80);
			$ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['pre_emphasis'] = (bool) ($TrackFlagsRaw & 0x40);

			$offset += 13; // reserved

			$ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points']          = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
			$offset += 1;

			for ($index = 0; $index < $ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points']; $index++) {
				$IndexSampleOffset = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 8));
				$offset += 8;
				$IndexNumber       = getid3_lib::BigEndian2Int(substr($METAdataBlockData, $offset, 1));
				$offset += 1;

				$offset += 3; // reserved

				$ThisFileInfo['flac']['CUESHEET']['tracks'][$TrackNumber]['indexes'][$IndexNumber] = $IndexSampleOffset;
			}
		}
		return true;
	}

}

?>