getid3_mp3::RecursiveFrameScanning( int $offset, int $nextframetestoffset, bool $ScanAsCBR ): bool

1166	public function RecursiveFrameScanning(&$offset, &$nextframetestoffset, $ScanAsCBR) {1167		$info = &$this->getid3->info;1168		$firstframetestarray = array('error' => array(), 'warning'=> array(), 'avdataend' => $info['avdataend'], 'avdataoffset' => $info['avdataoffset']);1169		$this->decodeMPEGaudioHeader($offset, $firstframetestarray, false);1170 1171		$info['mp3_validity_check_bitrates'] = array();1172		for ($i = 0; $i < $this->mp3_valid_check_frames; $i++) {1173			// check next (default: 50) frames for validity, to make sure we haven't run across a false synch1174			if (($nextframetestoffset + 4) >= $info['avdataend']) {1175				// end of file1176				return true;1177			}1178 1179			$nextframetestarray = array('error' => array(), 'warning' => array(), 'avdataend' => $info['avdataend'], 'avdataoffset'=>$info['avdataoffset']);1180			if ($this->decodeMPEGaudioHeader($nextframetestoffset, $nextframetestarray, false)) {1181				getid3_lib::safe_inc($info['mp3_validity_check_bitrates'][$nextframetestarray['mpeg']['audio']['bitrate']]);1182				if ($ScanAsCBR) {1183					// force CBR mode, used for trying to pick out invalid audio streams with valid(?) VBR headers, or VBR streams with no VBR header1184					if (!isset($nextframetestarray['mpeg']['audio']['bitrate']) || !isset($firstframetestarray['mpeg']['audio']['bitrate']) || ($nextframetestarray['mpeg']['audio']['bitrate'] != $firstframetestarray['mpeg']['audio']['bitrate'])) {1185						return false;1186					}1187				}1188 1189 1190				// next frame is OK, get ready to check the one after that1191				if (isset($nextframetestarray['mpeg']['audio']['framelength']) && ($nextframetestarray['mpeg']['audio']['framelength'] > 0)) {1192					$nextframetestoffset += (int) $nextframetestarray['mpeg']['audio']['framelength'];1193				} else {1194					$this->error('Frame at offset ('.$offset.') is has an invalid frame length.');1195					return false;1196				}1197 1198			} elseif (!empty($firstframetestarray['mpeg']['audio']['framelength']) && (($nextframetestoffset + $firstframetestarray['mpeg']['audio']['framelength']) > $info['avdataend'])) {1199 1200				// it's not the end of the file, but there's not enough data left for another frame, so assume it's garbage/padding and return OK1201				return true;1202 1203			} else {1204 1205				// next frame is not valid, note the error and fail, so scanning can contiue for a valid frame sequence1206				$this->warning('Frame at offset ('.$offset.') is valid, but the next one at ('.$nextframetestoffset.') is not.');1207 1208				return false;1209			}1210		}1211		return true;1212	}