Initial commit

1 files changed, 541 insertions, 0 deletions

diff --git a/includes/getid3/module.audio.aac.php b/includes/getid3/module.audio.aac.php
new file mode 100644
index 0000000..d4f04b8
--- /dev/null
+++ b/includes/getid3/module.audio.aac.php
@@ -0,0 +1,541 @@
+<?php
+
+/////////////////////////////////////////////////////////////////
+/// getID3() by James Heinrich <info@getid3.org>               //
+//  available at https://github.com/JamesHeinrich/getID3       //
+//            or https://www.getid3.org                        //
+//            or http://getid3.sourceforge.net                 //
+//  see readme.txt for more details                            //
+/////////////////////////////////////////////////////////////////
+//                                                             //
+// module.audio.aac.php                                        //
+// module for analyzing AAC Audio files                        //
+// dependencies: NONE                                          //
+//                                                            ///
+/////////////////////////////////////////////////////////////////
+
+if (!defined('GETID3_INCLUDEPATH')) { // prevent path-exposing attacks that access modules directly on public webservers
+	exit;
+}
+
+class getid3_aac extends getid3_handler
+{
+	/**
+	 * @return bool
+	 */
+	public function Analyze() {
+		$info = &$this->getid3->info;
+		$this->fseek($info['avdataoffset']);
+		if ($this->fread(4) == 'ADIF') {
+			$this->getAACADIFheaderFilepointer();
+		} else {
+			$this->getAACADTSheaderFilepointer();
+		}
+		return true;
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function getAACADIFheaderFilepointer() {
+		$info = &$this->getid3->info;
+		$info['fileformat']          = 'aac';
+		$info['audio']['dataformat'] = 'aac';
+		$info['audio']['lossless']   = false;
+
+		$this->fseek($info['avdataoffset']);
+		$AACheader = $this->fread(1024);
+		$offset    = 0;
+
+		if (substr($AACheader, 0, 4) == 'ADIF') {
+
+			// http://faac.sourceforge.net/wiki/index.php?page=ADIF
+
+			// http://libmpeg.org/mpeg4/doc/w2203tfs.pdf
+			// adif_header() {
+			//     adif_id                                32
+			//     copyright_id_present                    1
+			//     if( copyright_id_present )
+			//         copyright_id                       72
+			//     original_copy                           1
+			//     home                                    1
+			//     bitstream_type                          1
+			//     bitrate                                23
+			//     num_program_config_elements             4
+			//     for (i = 0; i < num_program_config_elements + 1; i++ ) {
+			//         if( bitstream_type == '0' )
+			//             adif_buffer_fullness           20
+			//         program_config_element()
+			//     }
+			// }
+
+			$AACheaderBitstream = getid3_lib::BigEndian2Bin($AACheader);
+			$bitoffset          = 0;
+
+			$info['aac']['header_type']                   = 'ADIF';
+			$bitoffset += 32;
+			$info['aac']['header']['mpeg_version']        = 4;
+
+			$info['aac']['header']['copyright']           = substr($AACheaderBitstream, $bitoffset, 1) == '1';
+			$bitoffset += 1;
+			if ($info['aac']['header']['copyright']) {
+				$info['aac']['header']['copyright_id']    = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 72));
+				$bitoffset += 72;
+			}
+			$info['aac']['header']['original_copy']       = substr($AACheaderBitstream, $bitoffset, 1) == '1';
+			$bitoffset += 1;
+			$info['aac']['header']['home']                = substr($AACheaderBitstream, $bitoffset, 1) == '1';
+			$bitoffset += 1;
+			$info['aac']['header']['is_vbr']              = substr($AACheaderBitstream, $bitoffset, 1) == '1';
+			$bitoffset += 1;
+			if ($info['aac']['header']['is_vbr']) {
+				$info['audio']['bitrate_mode']            = 'vbr';
+				$info['aac']['header']['bitrate_max']     = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
+				$bitoffset += 23;
+			} else {
+				$info['audio']['bitrate_mode']            = 'cbr';
+				$info['aac']['header']['bitrate']         = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 23));
+				$bitoffset += 23;
+				$info['audio']['bitrate']                 = $info['aac']['header']['bitrate'];
+			}
+			if ($info['audio']['bitrate'] == 0) {
+				$this->error('Corrupt AAC file: bitrate_audio == zero');
+				return false;
+			}
+			$info['aac']['header']['num_program_configs'] = 1 + getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+			$bitoffset += 4;
+
+			for ($i = 0; $i < $info['aac']['header']['num_program_configs']; $i++) {
+				// http://www.audiocoding.com/wiki/index.php?page=program_config_element
+
+				// buffer_fullness                       20
+
+				// element_instance_tag                   4
+				// object_type                            2
+				// sampling_frequency_index               4
+				// num_front_channel_elements             4
+				// num_side_channel_elements              4
+				// num_back_channel_elements              4
+				// num_lfe_channel_elements               2
+				// num_assoc_data_elements                3
+				// num_valid_cc_elements                  4
+				// mono_mixdown_present                   1
+				// mono_mixdown_element_number            4   if mono_mixdown_present == 1
+				// stereo_mixdown_present                 1
+				// stereo_mixdown_element_number          4   if stereo_mixdown_present == 1
+				// matrix_mixdown_idx_present             1
+				// matrix_mixdown_idx                     2   if matrix_mixdown_idx_present == 1
+				// pseudo_surround_enable                 1   if matrix_mixdown_idx_present == 1
+				// for (i = 0; i < num_front_channel_elements; i++) {
+				//     front_element_is_cpe[i]            1
+				//     front_element_tag_select[i]        4
+				// }
+				// for (i = 0; i < num_side_channel_elements; i++) {
+				//     side_element_is_cpe[i]             1
+				//     side_element_tag_select[i]         4
+				// }
+				// for (i = 0; i < num_back_channel_elements; i++) {
+				//     back_element_is_cpe[i]             1
+				//     back_element_tag_select[i]         4
+				// }
+				// for (i = 0; i < num_lfe_channel_elements; i++) {
+				//     lfe_element_tag_select[i]          4
+				// }
+				// for (i = 0; i < num_assoc_data_elements; i++) {
+				//     assoc_data_element_tag_select[i]   4
+				// }
+				// for (i = 0; i < num_valid_cc_elements; i++) {
+				//     cc_element_is_ind_sw[i]            1
+				//     valid_cc_element_tag_select[i]     4
+				// }
+				// byte_alignment()                       VAR
+				// comment_field_bytes                    8
+				// for (i = 0; i < comment_field_bytes; i++) {
+				//     comment_field_data[i]              8
+				// }
+
+				if (!$info['aac']['header']['is_vbr']) {
+					$info['aac']['program_configs'][$i]['buffer_fullness']        = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 20));
+					$bitoffset += 20;
+				}
+				$info['aac']['program_configs'][$i]['element_instance_tag']       = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+				$bitoffset += 4;
+				$info['aac']['program_configs'][$i]['object_type']                = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
+				$bitoffset += 2;
+				$info['aac']['program_configs'][$i]['sampling_frequency_index']   = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+				$bitoffset += 4;
+				$info['aac']['program_configs'][$i]['num_front_channel_elements'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+				$bitoffset += 4;
+				$info['aac']['program_configs'][$i]['num_side_channel_elements']  = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+				$bitoffset += 4;
+				$info['aac']['program_configs'][$i]['num_back_channel_elements']  = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+				$bitoffset += 4;
+				$info['aac']['program_configs'][$i]['num_lfe_channel_elements']   = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
+				$bitoffset += 2;
+				$info['aac']['program_configs'][$i]['num_assoc_data_elements']    = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 3));
+				$bitoffset += 3;
+				$info['aac']['program_configs'][$i]['num_valid_cc_elements']      = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+				$bitoffset += 4;
+				$info['aac']['program_configs'][$i]['mono_mixdown_present']       = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+				$bitoffset += 1;
+				if ($info['aac']['program_configs'][$i]['mono_mixdown_present']) {
+					$info['aac']['program_configs'][$i]['mono_mixdown_element_number']    = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				$info['aac']['program_configs'][$i]['stereo_mixdown_present']             = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+				$bitoffset += 1;
+				if ($info['aac']['program_configs'][$i]['stereo_mixdown_present']) {
+					$info['aac']['program_configs'][$i]['stereo_mixdown_element_number']  = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				$info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']         = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+				$bitoffset += 1;
+				if ($info['aac']['program_configs'][$i]['matrix_mixdown_idx_present']) {
+					$info['aac']['program_configs'][$i]['matrix_mixdown_idx']             = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 2));
+					$bitoffset += 2;
+					$info['aac']['program_configs'][$i]['pseudo_surround_enable']         = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+					$bitoffset += 1;
+				}
+				for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_front_channel_elements']; $j++) {
+					$info['aac']['program_configs'][$i]['front_element_is_cpe'][$j]     = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+					$bitoffset += 1;
+					$info['aac']['program_configs'][$i]['front_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_side_channel_elements']; $j++) {
+					$info['aac']['program_configs'][$i]['side_element_is_cpe'][$j]     = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+					$bitoffset += 1;
+					$info['aac']['program_configs'][$i]['side_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_back_channel_elements']; $j++) {
+					$info['aac']['program_configs'][$i]['back_element_is_cpe'][$j]     = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+					$bitoffset += 1;
+					$info['aac']['program_configs'][$i]['back_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_lfe_channel_elements']; $j++) {
+					$info['aac']['program_configs'][$i]['lfe_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_assoc_data_elements']; $j++) {
+					$info['aac']['program_configs'][$i]['assoc_data_element_tag_select'][$j] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+				for ($j = 0; $j < $info['aac']['program_configs'][$i]['num_valid_cc_elements']; $j++) {
+					$info['aac']['program_configs'][$i]['cc_element_is_ind_sw'][$j]          = (bool) getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 1));
+					$bitoffset += 1;
+					$info['aac']['program_configs'][$i]['valid_cc_element_tag_select'][$j]   = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 4));
+					$bitoffset += 4;
+				}
+
+				$bitoffset = ceil($bitoffset / 8) * 8;
+
+				$info['aac']['program_configs'][$i]['comment_field_bytes'] = getid3_lib::Bin2Dec(substr($AACheaderBitstream, $bitoffset, 8));
+				$bitoffset += 8;
+				$info['aac']['program_configs'][$i]['comment_field']       = getid3_lib::Bin2String(substr($AACheaderBitstream, $bitoffset, 8 * $info['aac']['program_configs'][$i]['comment_field_bytes']));
+				$bitoffset += 8 * $info['aac']['program_configs'][$i]['comment_field_bytes'];
+
+
+				$info['aac']['header']['profile']                           = self::AACprofileLookup($info['aac']['program_configs'][$i]['object_type'], $info['aac']['header']['mpeg_version']);
+				$info['aac']['program_configs'][$i]['sampling_frequency']   = self::AACsampleRateLookup($info['aac']['program_configs'][$i]['sampling_frequency_index']);
+				$info['audio']['sample_rate']                               = $info['aac']['program_configs'][$i]['sampling_frequency'];
+				$info['audio']['channels']                                  = self::AACchannelCountCalculate($info['aac']['program_configs'][$i]);
+				if ($info['aac']['program_configs'][$i]['comment_field']) {
+					$info['aac']['comments'][]                          = $info['aac']['program_configs'][$i]['comment_field'];
+				}
+			}
+			$info['playtime_seconds'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['audio']['bitrate'];
+
+			$info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
+
+
+
+			return true;
+
+		} else {
+
+			unset($info['fileformat']);
+			unset($info['aac']);
+			$this->error('AAC-ADIF synch not found at offset '.$info['avdataoffset'].' (expected "ADIF", found "'.substr($AACheader, 0, 4).'" instead)');
+			return false;
+
+		}
+
+	}
+
+	/**
+	 * @param int  $MaxFramesToScan
+	 * @param bool $ReturnExtendedInfo
+	 *
+	 * @return bool
+	 */
+	public function getAACADTSheaderFilepointer($MaxFramesToScan=1000000, $ReturnExtendedInfo=false) {
+		$info = &$this->getid3->info;
+
+		// based loosely on code from AACfile by Jurgen Faul  <jfaulØgmx.de>
+		// http://jfaul.de/atl  or  http://j-faul.virtualave.net/atl/atl.html
+
+
+		// http://faac.sourceforge.net/wiki/index.php?page=ADTS // dead link
+		// http://wiki.multimedia.cx/index.php?title=ADTS
+
+		// * ADTS Fixed Header: these don't change from frame to frame
+		// syncword                                       12    always: '111111111111'
+		// ID                                              1    0: MPEG-4, 1: MPEG-2
+		// MPEG layer                                      2    If you send AAC in MPEG-TS, set to 0
+		// protection_absent                               1    0: CRC present; 1: no CRC
+		// profile                                         2    0: AAC Main; 1: AAC LC (Low Complexity); 2: AAC SSR (Scalable Sample Rate); 3: AAC LTP (Long Term Prediction)
+		// sampling_frequency_index                        4    15 not allowed
+		// private_bit                                     1    usually 0
+		// channel_configuration                           3
+		// original/copy                                   1    0: original; 1: copy
+		// home                                            1    usually 0
+		// emphasis                                        2    only if ID == 0 (ie MPEG-4)  // not present in some documentation?
+
+		// * ADTS Variable Header: these can change from frame to frame
+		// copyright_identification_bit                    1
+		// copyright_identification_start                  1
+		// aac_frame_length                               13    length of the frame including header (in bytes)
+		// adts_buffer_fullness                           11    0x7FF indicates VBR
+		// no_raw_data_blocks_in_frame                     2
+
+		// * ADTS Error check
+		// crc_check                                      16    only if protection_absent == 0
+
+		$byteoffset  = $info['avdataoffset'];
+		$framenumber = 0;
+
+		// Init bit pattern array
+		static $decbin = array();
+
+		// Populate $bindec
+		for ($i = 0; $i < 256; $i++) {
+			$decbin[chr($i)] = str_pad(decbin($i), 8, '0', STR_PAD_LEFT);
+		}
+
+		// used to calculate bitrate below
+		$BitrateCache = array();
+
+
+		while (true) {
+			// breaks out when end-of-file encountered, or invalid data found,
+			// or MaxFramesToScan frames have been scanned
+
+			if (!getid3_lib::intValueSupported($byteoffset)) {
+				$this->warning('Unable to parse AAC file beyond '.$this->ftell().' (PHP does not support file operations beyond '.round(PHP_INT_MAX / 1073741824).'GB)');
+				return false;
+			}
+			$this->fseek($byteoffset);
+
+			// First get substring
+			$substring = $this->fread(9); // header is 7 bytes (or 9 if CRC is present)
+			$substringlength = strlen($substring);
+			if ($substringlength != 9) {
+				$this->error('Failed to read 7 bytes at offset '.($this->ftell() - $substringlength).' (only read '.$substringlength.' bytes)');
+				return false;
+			}
+			// this would be easier with 64-bit math, but split it up to allow for 32-bit:
+			$header1 = getid3_lib::BigEndian2Int(substr($substring, 0, 2));
+			$header2 = getid3_lib::BigEndian2Int(substr($substring, 2, 4));
+			$header3 = getid3_lib::BigEndian2Int(substr($substring, 6, 1));
+
+			$info['aac']['header']['raw']['syncword']          = ($header1 & 0xFFF0) >> 4;
+			if ($info['aac']['header']['raw']['syncword'] != 0x0FFF) {
+				$this->error('Synch pattern (0x0FFF) not found at offset '.($this->ftell() - $substringlength).' (found 0x0'.strtoupper(dechex($info['aac']['header']['raw']['syncword'])).' instead)');
+				//if ($info['fileformat'] == 'aac') {
+				//	return true;
+				//}
+				unset($info['aac']);
+				return false;
+			}
+
+			// Gather info for first frame only - this takes time to do 1000 times!
+			if ($framenumber == 0) {
+				$info['aac']['header_type']                      = 'ADTS';
+				$info['fileformat']                              = 'aac';
+				$info['audio']['dataformat']                     = 'aac';
+
+				$info['aac']['header']['raw']['mpeg_version']      = ($header1 & 0x0008) >> 3;
+				$info['aac']['header']['raw']['mpeg_layer']        = ($header1 & 0x0006) >> 1;
+				$info['aac']['header']['raw']['protection_absent'] = ($header1 & 0x0001) >> 0;
+
+				$info['aac']['header']['raw']['profile_code']      = ($header2 & 0xC0000000) >> 30;
+				$info['aac']['header']['raw']['sample_rate_code']  = ($header2 & 0x3C000000) >> 26;
+				$info['aac']['header']['raw']['private_stream']    = ($header2 & 0x02000000) >> 25;
+				$info['aac']['header']['raw']['channels_code']     = ($header2 & 0x01C00000) >> 22;
+				$info['aac']['header']['raw']['original']          = ($header2 & 0x00200000) >> 21;
+				$info['aac']['header']['raw']['home']              = ($header2 & 0x00100000) >> 20;
+				$info['aac']['header']['raw']['copyright_stream']  = ($header2 & 0x00080000) >> 19;
+				$info['aac']['header']['raw']['copyright_start']   = ($header2 & 0x00040000) >> 18;
+				$info['aac']['header']['raw']['frame_length']      = ($header2 & 0x0003FFE0) >>  5;
+
+				$info['aac']['header']['mpeg_version']     = ($info['aac']['header']['raw']['mpeg_version']      ? 2    : 4);
+				$info['aac']['header']['crc_present']      = ($info['aac']['header']['raw']['protection_absent'] ? false: true);
+				$info['aac']['header']['profile']          = self::AACprofileLookup($info['aac']['header']['raw']['profile_code'], $info['aac']['header']['mpeg_version']);
+				$info['aac']['header']['sample_frequency'] = self::AACsampleRateLookup($info['aac']['header']['raw']['sample_rate_code']);
+				$info['aac']['header']['private']          = (bool) $info['aac']['header']['raw']['private_stream'];
+				$info['aac']['header']['original']         = (bool) $info['aac']['header']['raw']['original'];
+				$info['aac']['header']['home']             = (bool) $info['aac']['header']['raw']['home'];
+				$info['aac']['header']['channels']         = (($info['aac']['header']['raw']['channels_code'] == 7) ? 8 : $info['aac']['header']['raw']['channels_code']);
+				if ($ReturnExtendedInfo) {
+					$info['aac'][$framenumber]['copyright_id_bit']   = (bool) $info['aac']['header']['raw']['copyright_stream'];
+					$info['aac'][$framenumber]['copyright_id_start'] = (bool) $info['aac']['header']['raw']['copyright_start'];
+				}
+
+				if ($info['aac']['header']['raw']['mpeg_layer'] != 0) {
+					$this->warning('Layer error - expected "0", found "'.$info['aac']['header']['raw']['mpeg_layer'].'" instead');
+				}
+				if ($info['aac']['header']['sample_frequency'] == 0) {
+					$this->error('Corrupt AAC file: sample_frequency == zero');
+					return false;
+				}
+
+				$info['audio']['sample_rate'] = $info['aac']['header']['sample_frequency'];
+				$info['audio']['channels']    = $info['aac']['header']['channels'];
+			}
+
+			$FrameLength = ($header2 & 0x0003FFE0) >>  5;
+
+			if (!isset($BitrateCache[$FrameLength])) {
+				$BitrateCache[$FrameLength] = ($info['aac']['header']['sample_frequency'] / 1024) * $FrameLength * 8;
+			}
+			getid3_lib::safe_inc($info['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]], 1);
+
+			$info['aac'][$framenumber]['aac_frame_length']     = $FrameLength;
+
+			$info['aac'][$framenumber]['adts_buffer_fullness'] = (($header2 & 0x0000001F) << 6) & (($header3 & 0xFC) >> 2);
+			if ($info['aac'][$framenumber]['adts_buffer_fullness'] == 0x07FF) {
+				$info['audio']['bitrate_mode'] = 'vbr';
+			} else {
+				$info['audio']['bitrate_mode'] = 'cbr';
+			}
+			$info['aac'][$framenumber]['num_raw_data_blocks']  = (($header3 & 0x03) >> 0);
+
+			if ($info['aac']['header']['crc_present']) {
+				//$info['aac'][$framenumber]['crc'] = getid3_lib::BigEndian2Int(substr($substring, 7, 2);
+			}
+
+			if (!$ReturnExtendedInfo) {
+				unset($info['aac'][$framenumber]);
+			}
+
+			/*
+			$rounded_precision = 5000;
+			$info['aac']['bitrate_distribution_rounded'] = array();
+			foreach ($info['aac']['bitrate_distribution'] as $bitrate => $count) {
+				$rounded_bitrate = round($bitrate / $rounded_precision) * $rounded_precision;
+				getid3_lib::safe_inc($info['aac']['bitrate_distribution_rounded'][$rounded_bitrate], $count);
+			}
+			ksort($info['aac']['bitrate_distribution_rounded']);
+			*/
+
+			$byteoffset += $FrameLength;
+			if ((++$framenumber < $MaxFramesToScan) && (($byteoffset + 10) < $info['avdataend'])) {
+
+				// keep scanning
+
+			} else {
+
+				$info['aac']['frames']    = $framenumber;
+				$info['playtime_seconds'] = ($info['avdataend'] / $byteoffset) * (($framenumber * 1024) / $info['aac']['header']['sample_frequency']);  // (1 / % of file scanned) * (samples / (samples/sec)) = seconds
+				if ($info['playtime_seconds'] == 0) {
+					$this->error('Corrupt AAC file: playtime_seconds == zero');
+					return false;
+				}
+				$info['audio']['bitrate']    = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
+				ksort($info['aac']['bitrate_distribution']);
+
+				$info['audio']['encoder_options'] = $info['aac']['header_type'].' '.$info['aac']['header']['profile'];
+
+				return true;
+
+			}
+		}
+		// should never get here.
+	}
+
+	/**
+	 * @param int $samplerateid
+	 *
+	 * @return int|string
+	 */
+	public static function AACsampleRateLookup($samplerateid) {
+		static $AACsampleRateLookup = array();
+		if (empty($AACsampleRateLookup)) {
+			$AACsampleRateLookup[0]  = 96000;
+			$AACsampleRateLookup[1]  = 88200;
+			$AACsampleRateLookup[2]  = 64000;
+			$AACsampleRateLookup[3]  = 48000;
+			$AACsampleRateLookup[4]  = 44100;
+			$AACsampleRateLookup[5]  = 32000;
+			$AACsampleRateLookup[6]  = 24000;
+			$AACsampleRateLookup[7]  = 22050;
+			$AACsampleRateLookup[8]  = 16000;
+			$AACsampleRateLookup[9]  = 12000;
+			$AACsampleRateLookup[10] = 11025;
+			$AACsampleRateLookup[11] = 8000;
+			$AACsampleRateLookup[12] = 0;
+			$AACsampleRateLookup[13] = 0;
+			$AACsampleRateLookup[14] = 0;
+			$AACsampleRateLookup[15] = 0;
+		}
+		return (isset($AACsampleRateLookup[$samplerateid]) ? $AACsampleRateLookup[$samplerateid] : 'invalid');
+	}
+
+	/**
+	 * @param int $profileid
+	 * @param int $mpegversion
+	 *
+	 * @return string
+	 */
+	public static function AACprofileLookup($profileid, $mpegversion) {
+		static $AACprofileLookup = array();
+		if (empty($AACprofileLookup)) {
+			$AACprofileLookup[2][0]  = 'Main profile';
+			$AACprofileLookup[2][1]  = 'Low Complexity profile (LC)';
+			$AACprofileLookup[2][2]  = 'Scalable Sample Rate profile (SSR)';
+			$AACprofileLookup[2][3]  = '(reserved)';
+			$AACprofileLookup[4][0]  = 'AAC_MAIN';
+			$AACprofileLookup[4][1]  = 'AAC_LC';
+			$AACprofileLookup[4][2]  = 'AAC_SSR';
+			$AACprofileLookup[4][3]  = 'AAC_LTP';
+		}
+		return (isset($AACprofileLookup[$mpegversion][$profileid]) ? $AACprofileLookup[$mpegversion][$profileid] : 'invalid');
+	}
+
+	/**
+	 * @param array $program_configs
+	 *
+	 * @return int
+	 */
+	public static function AACchannelCountCalculate($program_configs) {
+		$channels = 0;
+		for ($i = 0; $i < $program_configs['num_front_channel_elements']; $i++) {
+			$channels++;
+			if ($program_configs['front_element_is_cpe'][$i]) {
+				// each front element is channel pair (CPE = Channel Pair Element)
+				$channels++;
+			}
+		}
+		for ($i = 0; $i < $program_configs['num_side_channel_elements']; $i++) {
+			$channels++;
+			if ($program_configs['side_element_is_cpe'][$i]) {
+				// each side element is channel pair (CPE = Channel Pair Element)
+				$channels++;
+			}
+		}
+		for ($i = 0; $i < $program_configs['num_back_channel_elements']; $i++) {
+			$channels++;
+			if ($program_configs['back_element_is_cpe'][$i]) {
+				// each back element is channel pair (CPE = Channel Pair Element)
+				$channels++;
+			}
+		}
+		for ($i = 0; $i < $program_configs['num_lfe_channel_elements']; $i++) {
+			$channels++;
+		}
+		return $channels;
+	}
+
+}