getid3_mp3::getOnlyMPEGaudioInfoBruteForce

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Syntax Syntax

getid3_mp3::getOnlyMPEGaudioInfoBruteForce()

Return Return

(bool)

Source Source

File: wp-includes/ID3/module.audio.mp3.php

				$nextoffset += $framelength;
			}
			if (count($ActualFrameLengthValues) > 0) {
				$framelength = intval(round(array_sum($ActualFrameLengthValues) / count($ActualFrameLengthValues)));
			}
		}
		return $framelength;
	}

	/**
	 * @return bool
	 */
	public function getOnlyMPEGaudioInfoBruteForce() {
		$MPEGaudioHeaderDecodeCache   = array();
		$MPEGaudioHeaderValidCache    = array();
		$MPEGaudioHeaderLengthCache   = array();
		$MPEGaudioVersionLookup       = self::MPEGaudioVersionArray();
		$MPEGaudioLayerLookup         = self::MPEGaudioLayerArray();
		$MPEGaudioBitrateLookup       = self::MPEGaudioBitrateArray();
		$MPEGaudioFrequencyLookup     = self::MPEGaudioFrequencyArray();
		$MPEGaudioChannelModeLookup   = self::MPEGaudioChannelModeArray();
		$MPEGaudioModeExtensionLookup = self::MPEGaudioModeExtensionArray();
		$MPEGaudioEmphasisLookup      = self::MPEGaudioEmphasisArray();
		$LongMPEGversionLookup        = array();
		$LongMPEGlayerLookup          = array();
		$LongMPEGbitrateLookup        = array();
		$LongMPEGpaddingLookup        = array();
		$LongMPEGfrequencyLookup      = array();
		$Distribution['bitrate']      = array();
		$Distribution['frequency']    = array();
		$Distribution['layer']        = array();
		$Distribution['version']      = array();
		$Distribution['padding']      = array();

		$info = &$this->getid3->info;
		$this->fseek($info['avdataoffset']);

		$max_frames_scan = 5000;
		$frames_scanned  = 0;

		$previousvalidframe = $info['avdataoffset'];
		while ($this->ftell() < $info['avdataend']) {
			set_time_limit(30);
			$head4 = $this->fread(4);
			if (strlen($head4) < 4) {
				break;
			}
			if ($head4[0] != "\xFF") {
				for ($i = 1; $i < 4; $i++) {
					if ($head4[$i] == "\xFF") {
						$this->fseek($i - 4, SEEK_CUR);
						continue 2;
					}
				}
				continue;
			}
			if (!isset($MPEGaudioHeaderDecodeCache[$head4])) {
				$MPEGaudioHeaderDecodeCache[$head4] = self::MPEGaudioHeaderDecode($head4);
			}
			if (!isset($MPEGaudioHeaderValidCache[$head4])) {
				$MPEGaudioHeaderValidCache[$head4] = self::MPEGaudioHeaderValid($MPEGaudioHeaderDecodeCache[$head4], false, false);
			}
			if ($MPEGaudioHeaderValidCache[$head4]) {

				if (!isset($MPEGaudioHeaderLengthCache[$head4])) {
					$LongMPEGversionLookup[$head4]   = $MPEGaudioVersionLookup[$MPEGaudioHeaderDecodeCache[$head4]['version']];
					$LongMPEGlayerLookup[$head4]     = $MPEGaudioLayerLookup[$MPEGaudioHeaderDecodeCache[$head4]['layer']];
					$LongMPEGbitrateLookup[$head4]   = $MPEGaudioBitrateLookup[$LongMPEGversionLookup[$head4]][$LongMPEGlayerLookup[$head4]][$MPEGaudioHeaderDecodeCache[$head4]['bitrate']];
					$LongMPEGpaddingLookup[$head4]   = (bool) $MPEGaudioHeaderDecodeCache[$head4]['padding'];
					$LongMPEGfrequencyLookup[$head4] = $MPEGaudioFrequencyLookup[$LongMPEGversionLookup[$head4]][$MPEGaudioHeaderDecodeCache[$head4]['sample_rate']];
					$MPEGaudioHeaderLengthCache[$head4] = self::MPEGaudioFrameLength(
						$LongMPEGbitrateLookup[$head4],
						$LongMPEGversionLookup[$head4],
						$LongMPEGlayerLookup[$head4],
						$LongMPEGpaddingLookup[$head4],
						$LongMPEGfrequencyLookup[$head4]);
				}
				if ($MPEGaudioHeaderLengthCache[$head4] > 4) {
					$WhereWeWere = $this->ftell();
					$this->fseek($MPEGaudioHeaderLengthCache[$head4] - 4, SEEK_CUR);
					$next4 = $this->fread(4);
					if ($next4[0] == "\xFF") {
						if (!isset($MPEGaudioHeaderDecodeCache[$next4])) {
							$MPEGaudioHeaderDecodeCache[$next4] = self::MPEGaudioHeaderDecode($next4);
						}
						if (!isset($MPEGaudioHeaderValidCache[$next4])) {
							$MPEGaudioHeaderValidCache[$next4] = self::MPEGaudioHeaderValid($MPEGaudioHeaderDecodeCache[$next4], false, false);
						}
						if ($MPEGaudioHeaderValidCache[$next4]) {
							$this->fseek(-4, SEEK_CUR);

							$Distribution['bitrate'][$LongMPEGbitrateLookup[$head4]] = isset($Distribution['bitrate'][$LongMPEGbitrateLookup[$head4]]) ? ++$Distribution['bitrate'][$LongMPEGbitrateLookup[$head4]] : 1;
							$Distribution['layer'][$LongMPEGlayerLookup[$head4]] = isset($Distribution['layer'][$LongMPEGlayerLookup[$head4]]) ? ++$Distribution['layer'][$LongMPEGlayerLookup[$head4]] : 1;
							$Distribution['version'][$LongMPEGversionLookup[$head4]] = isset($Distribution['version'][$LongMPEGversionLookup[$head4]]) ? ++$Distribution['version'][$LongMPEGversionLookup[$head4]] : 1;
							$Distribution['padding'][intval($LongMPEGpaddingLookup[$head4])] = isset($Distribution['padding'][intval($LongMPEGpaddingLookup[$head4])]) ? ++$Distribution['padding'][intval($LongMPEGpaddingLookup[$head4])] : 1;
							$Distribution['frequency'][$LongMPEGfrequencyLookup[$head4]] = isset($Distribution['frequency'][$LongMPEGfrequencyLookup[$head4]]) ? ++$Distribution['frequency'][$LongMPEGfrequencyLookup[$head4]] : 1;
							if (++$frames_scanned >= $max_frames_scan) {
								$pct_data_scanned = ($this->ftell() - $info['avdataoffset']) / ($info['avdataend'] - $info['avdataoffset']);
								$this->warning('too many MPEG audio frames to scan, only scanned first '.$max_frames_scan.' frames ('.number_format($pct_data_scanned * 100, 1).'% of file) and extrapolated distribution, playtime and bitrate may be incorrect.');
								foreach ($Distribution as $key1 => $value1) {
									foreach ($value1 as $key2 => $value2) {
										$Distribution[$key1][$key2] = round($value2 / $pct_data_scanned);
									}
								}
								break;
							}
							continue;
						}
					}
					unset($next4);
					$this->fseek($WhereWeWere - 3);
				}

			}
		}
		foreach ($Distribution as $key => $value) {
			ksort($Distribution[$key], SORT_NUMERIC);
		}
		ksort($Distribution['version'], SORT_STRING);
		$info['mpeg']['audio']['bitrate_distribution']   = $Distribution['bitrate'];
		$info['mpeg']['audio']['frequency_distribution'] = $Distribution['frequency'];
		$info['mpeg']['audio']['layer_distribution']     = $Distribution['layer'];
		$info['mpeg']['audio']['version_distribution']   = $Distribution['version'];
		$info['mpeg']['audio']['padding_distribution']   = $Distribution['padding'];
		if (count($Distribution['version']) > 1) {
			$this->error('Corrupt file - more than one MPEG version detected');
		}
		if (count($Distribution['layer']) > 1) {
			$this->error('Corrupt file - more than one MPEG layer detected');
		}
		if (count($Distribution['frequency']) > 1) {
			$this->error('Corrupt file - more than one MPEG sample rate detected');
		}


		$bittotal = 0;
		foreach ($Distribution['bitrate'] as $bitratevalue => $bitratecount) {
			if ($bitratevalue != 'free') {
				$bittotal += ($bitratevalue * $bitratecount);
			}
		}
		$info['mpeg']['audio']['frame_count']  = array_sum($Distribution['bitrate']);
		if ($info['mpeg']['audio']['frame_count'] == 0) {
			$this->error('no MPEG audio frames found');
			return false;
		}

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