/**
* @staticvar type $MPEGaudioVersionLookup
* @staticvar type $MPEGaudioLayerLookup
* @staticvar type $MPEGaudioBitrateLookup
*
* @param type $avdataoffset
* @param bool $BitrateHistogram
*
* @return bool
*/
public function getOnlyMPEGaudioInfo($avdataoffset, $BitrateHistogram = false)
{
// looks for synch, decodes MPEG audio header
$info =& $this->getGetId3()->info;
static $MPEGaudioVersionLookup;
static $MPEGaudioLayerLookup;
static $MPEGaudioBitrateLookup;
if (empty($MPEGaudioVersionLookup)) {
$MPEGaudioVersionLookup = self::MPEGaudioVersionArray();
$MPEGaudioLayerLookup = self::MPEGaudioLayerArray();
$MPEGaudioBitrateLookup = self::MPEGaudioBitrateArray();
}
fseek($this->getGetId3()->fp, $avdataoffset, SEEK_SET);
$sync_seek_buffer_size = min(128 * 1024, $info['avdataend'] - $avdataoffset);
if ($sync_seek_buffer_size <= 0) {
$info['error'][] = 'Invalid $sync_seek_buffer_size at offset ' . $avdataoffset;
return false;
}
$header = fread($this->getGetId3()->fp, $sync_seek_buffer_size);
$sync_seek_buffer_size = strlen($header);
$SynchSeekOffset = 0;
while ($SynchSeekOffset < $sync_seek_buffer_size) {
if ($avdataoffset + $SynchSeekOffset < $info['avdataend'] && !feof($this->getGetId3()->fp)) {
if ($SynchSeekOffset > $sync_seek_buffer_size) {
// if a synch's not found within the first 128k bytes, then give up
$info['error'][] = 'Could not find valid MPEG audio synch within the first ' . round($sync_seek_buffer_size / 1024) . 'kB';
if (isset($info['audio']['bitrate'])) {
unset($info['audio']['bitrate']);
}
if (isset($info['mpeg']['audio'])) {
unset($info['mpeg']['audio']);
}
if (empty($info['mpeg'])) {
unset($info['mpeg']);
}
return false;
} elseif (feof($this->getGetId3()->fp)) {
$info['error'][] = 'Could not find valid MPEG audio synch before end of file';
if (isset($info['audio']['bitrate'])) {
unset($info['audio']['bitrate']);
}
if (isset($info['mpeg']['audio'])) {
unset($info['mpeg']['audio']);
}
if (isset($info['mpeg']) && (!is_array($info['mpeg']) || count($info['mpeg']) == 0)) {
unset($info['mpeg']);
}
return false;
}
}
if ($SynchSeekOffset + 1 >= strlen($header)) {
$info['error'][] = 'Could not find valid MPEG synch before end of file';
return false;
}
if ($header[$SynchSeekOffset] == "ÿ" && $header[$SynchSeekOffset + 1] > "à") {
// synch detected
if (!isset($FirstFrameThisfileInfo) && !isset($info['mpeg']['audio'])) {
$FirstFrameThisfileInfo = $info;
$FirstFrameAVDataOffset = $avdataoffset + $SynchSeekOffset;
if (!$this->decodeMPEGaudioHeader($FirstFrameAVDataOffset, $FirstFrameThisfileInfo, false)) {
// if this is the first valid MPEG-audio frame, save it in case it's a VBR header frame and there's
// garbage between this frame and a valid sequence of MPEG-audio frames, to be restored below
unset($FirstFrameThisfileInfo);
}
}
$dummy = $info;
// only overwrite real data if valid header found
if ($this->decodeMPEGaudioHeader($avdataoffset + $SynchSeekOffset, $dummy, true)) {
$info = $dummy;
$info['avdataoffset'] = $avdataoffset + $SynchSeekOffset;
switch (isset($info['fileformat']) ? $info['fileformat'] : '') {
case '':
case 'id3':
case 'ape':
case 'mp3':
$info['fileformat'] = 'mp3';
$info['audio']['dataformat'] = 'mp3';
break;
}
if (isset($FirstFrameThisfileInfo['mpeg']['audio']['bitrate_mode']) && $FirstFrameThisfileInfo['mpeg']['audio']['bitrate_mode'] == 'vbr') {
if (!(abs($info['audio']['bitrate'] - $FirstFrameThisfileInfo['audio']['bitrate']) <= 1)) {
// If there is garbage data between a valid VBR header frame and a sequence
// of valid MPEG-audio frames the VBR data is no longer discarded.
$info = $FirstFrameThisfileInfo;
$info['avdataoffset'] = $FirstFrameAVDataOffset;
$info['fileformat'] = 'mp3';
$info['audio']['dataformat'] = 'mp3';
$dummy = $info;
unset($dummy['mpeg']['audio']);
$GarbageOffsetStart = $FirstFrameAVDataOffset + $FirstFrameThisfileInfo['mpeg']['audio']['framelength'];
$GarbageOffsetEnd = $avdataoffset + $SynchSeekOffset;
if ($this->decodeMPEGaudioHeader($GarbageOffsetEnd, $dummy, true, true)) {
$info = $dummy;
$info['avdataoffset'] = $GarbageOffsetEnd;
$info['warning'][] = 'apparently-valid VBR header not used because could not find ' . self::GETID3_MP3_VALID_CHECK_FRAMES . ' consecutive MPEG-audio frames immediately after VBR header (garbage data for ' . ($GarbageOffsetEnd - $GarbageOffsetStart) . ' bytes between ' . $GarbageOffsetStart . ' and ' . $GarbageOffsetEnd . '), but did find valid CBR stream starting at ' . $GarbageOffsetEnd;
} else {
$info['warning'][] = 'using data from VBR header even though could not find ' . self::GETID3_MP3_VALID_CHECK_FRAMES . ' consecutive MPEG-audio frames immediately after VBR header (garbage data for ' . ($GarbageOffsetEnd - $GarbageOffsetStart) . ' bytes between ' . $GarbageOffsetStart . ' and ' . $GarbageOffsetEnd . ')';
}
}
}
if (isset($info['mpeg']['audio']['bitrate_mode']) && $info['mpeg']['audio']['bitrate_mode'] == 'vbr' && !isset($info['mpeg']['audio']['VBR_method'])) {
// VBR file with no VBR header
$BitrateHistogram = true;
}
if ($BitrateHistogram) {
$info['mpeg']['audio']['stereo_distribution'] = array('stereo' => 0, 'joint stereo' => 0, 'dual channel' => 0, 'mono' => 0);
$info['mpeg']['audio']['version_distribution'] = array('1' => 0, '2' => 0, '2.5' => 0);
if ($info['mpeg']['audio']['version'] == '1') {
if ($info['mpeg']['audio']['layer'] == 3) {
$info['mpeg']['audio']['bitrate_distribution'] = array('free' => 0, 32000 => 0, 40000 => 0, 48000 => 0, 56000 => 0, 64000 => 0, 80000 => 0, 96000 => 0, 112000 => 0, 128000 => 0, 160000 => 0, 192000 => 0, 224000 => 0, 256000 => 0, 320000 => 0);
} elseif ($info['mpeg']['audio']['layer'] == 2) {
$info['mpeg']['audio']['bitrate_distribution'] = array('free' => 0, 32000 => 0, 48000 => 0, 56000 => 0, 64000 => 0, 80000 => 0, 96000 => 0, 112000 => 0, 128000 => 0, 160000 => 0, 192000 => 0, 224000 => 0, 256000 => 0, 320000 => 0, 384000 => 0);
} elseif ($info['mpeg']['audio']['layer'] == 1) {
$info['mpeg']['audio']['bitrate_distribution'] = array('free' => 0, 32000 => 0, 64000 => 0, 96000 => 0, 128000 => 0, 160000 => 0, 192000 => 0, 224000 => 0, 256000 => 0, 288000 => 0, 320000 => 0, 352000 => 0, 384000 => 0, 416000 => 0, 448000 => 0);
}
} elseif ($info['mpeg']['audio']['layer'] == 1) {
$info['mpeg']['audio']['bitrate_distribution'] = array('free' => 0, 32000 => 0, 48000 => 0, 56000 => 0, 64000 => 0, 80000 => 0, 96000 => 0, 112000 => 0, 128000 => 0, 144000 => 0, 160000 => 0, 176000 => 0, 192000 => 0, 224000 => 0, 256000 => 0);
} else {
$info['mpeg']['audio']['bitrate_distribution'] = array('free' => 0, 8000 => 0, 16000 => 0, 24000 => 0, 32000 => 0, 40000 => 0, 48000 => 0, 56000 => 0, 64000 => 0, 80000 => 0, 96000 => 0, 112000 => 0, 128000 => 0, 144000 => 0, 160000 => 0);
}
$dummy = array('error' => $info['error'], 'warning' => $info['warning'], 'avdataend' => $info['avdataend'], 'avdataoffset' => $info['avdataoffset']);
$synchstartoffset = $info['avdataoffset'];
fseek($this->getGetId3()->fp, $info['avdataoffset'], SEEK_SET);
// you can play with these numbers:
$max_frames_scan = 50000;
$max_scan_segments = 10;
// don't play with these numbers:
$FastMode = false;
$SynchErrorsFound = 0;
$frames_scanned = 0;
$this_scan_segment = 0;
$frames_scan_per_segment = ceil($max_frames_scan / $max_scan_segments);
$pct_data_scanned = 0;
for ($current_segment = 0; $current_segment < $max_scan_segments; ++$current_segment) {
$frames_scanned_this_segment = 0;
if (ftell($this->getGetId3()->fp) >= $info['avdataend']) {
break;
}
$scan_start_offset[$current_segment] = max(ftell($this->getGetId3()->fp), $info['avdataoffset'] + round($current_segment * (($info['avdataend'] - $info['avdataoffset']) / $max_scan_segments)));
if ($current_segment > 0) {
fseek($this->getGetId3()->fp, $scan_start_offset[$current_segment], SEEK_SET);
$buffer_4k = fread($this->getGetId3()->fp, 4096);
for ($j = 0; $j < strlen($buffer_4k) - 4; ++$j) {
if ($buffer_4k[$j] == "ÿ" && $buffer_4k[$j + 1] > "à") {
// synch detected
if ($this->decodeMPEGaudioHeader($scan_start_offset[$current_segment] + $j, $dummy, false, false, $FastMode)) {
$calculated_next_offset = $scan_start_offset[$current_segment] + $j + $dummy['mpeg']['audio']['framelength'];
if ($this->decodeMPEGaudioHeader($calculated_next_offset, $dummy, false, false, $FastMode)) {
$scan_start_offset[$current_segment] += $j;
break;
}
}
}
}
}
$synchstartoffset = $scan_start_offset[$current_segment];
while ($this->decodeMPEGaudioHeader($synchstartoffset, $dummy, false, false, $FastMode)) {
$FastMode = true;
$thisframebitrate = $MPEGaudioBitrateLookup[$MPEGaudioVersionLookup[$dummy['mpeg']['audio']['raw']['version']]][$MPEGaudioLayerLookup[$dummy['mpeg']['audio']['raw']['layer']]][$dummy['mpeg']['audio']['raw']['bitrate']];
if (empty($dummy['mpeg']['audio']['framelength'])) {
++$SynchErrorsFound;
++$synchstartoffset;
} else {
Helper::safe_inc($info['mpeg']['audio']['bitrate_distribution'][$thisframebitrate]);
Helper::safe_inc($info['mpeg']['audio']['stereo_distribution'][$dummy['mpeg']['audio']['channelmode']]);
Helper::safe_inc($info['mpeg']['audio']['version_distribution'][$dummy['mpeg']['audio']['version']]);
$synchstartoffset += $dummy['mpeg']['audio']['framelength'];
}
++$frames_scanned;
if ($frames_scan_per_segment && ++$frames_scanned_this_segment >= $frames_scan_per_segment) {
$this_pct_scanned = (ftell($this->getGetId3()->fp) - $scan_start_offset[$current_segment]) / ($info['avdataend'] - $info['avdataoffset']);
if ($current_segment == 0 && $this_pct_scanned * $max_scan_segments >= 1) {
// file likely contains < $max_frames_scan, just scan as one segment
$max_scan_segments = 1;
$frames_scan_per_segment = $max_frames_scan;
} else {
$pct_data_scanned += $this_pct_scanned;
break;
}
}
}
}
if ($pct_data_scanned > 0) {
$info['warning'][] = 'too many MPEG audio frames to scan, only scanned ' . $frames_scanned . ' frames in ' . $max_scan_segments . ' segments (' . number_format($pct_data_scanned * 100, 1) . '% of file) and extrapolated distribution, playtime and bitrate may be incorrect.';
foreach ($info['mpeg']['audio'] as $key1 => $value1) {
if (!preg_match('#_distribution$#i', $key1)) {
continue;
}
foreach ($value1 as $key2 => $value2) {
$info['mpeg']['audio'][$key1][$key2] = round($value2 / $pct_data_scanned);
}
}
}
if ($SynchErrorsFound > 0) {
$info['warning'][] = 'Found ' . $SynchErrorsFound . ' synch errors in histogram analysis';
//return false;
}
$bittotal = 0;
$framecounter = 0;
foreach ($info['mpeg']['audio']['bitrate_distribution'] as $bitratevalue => $bitratecount) {
$framecounter += $bitratecount;
if ($bitratevalue != 'free') {
$bittotal += $bitratevalue * $bitratecount;
}
}
if ($framecounter == 0) {
$info['error'][] = 'Corrupt MP3 file: framecounter == zero';
return false;
}
$info['mpeg']['audio']['frame_count'] = Helper::CastAsInt($framecounter);
$info['mpeg']['audio']['bitrate'] = $bittotal / $framecounter;
$info['audio']['bitrate'] = $info['mpeg']['audio']['bitrate'];
// Definitively set VBR vs CBR, even if the Xing/LAME/VBRI header says differently
$distinct_bitrates = 0;
foreach ($info['mpeg']['audio']['bitrate_distribution'] as $bitrate_value => $bitrate_count) {
if ($bitrate_count > 0) {
++$distinct_bitrates;
}
}
if ($distinct_bitrates > 1) {
$info['mpeg']['audio']['bitrate_mode'] = 'vbr';
} else {
$info['mpeg']['audio']['bitrate_mode'] = 'cbr';
}
$info['audio']['bitrate_mode'] = $info['mpeg']['audio']['bitrate_mode'];
}
break;
// exit while()
}
}
++$SynchSeekOffset;
if ($avdataoffset + $SynchSeekOffset >= $info['avdataend']) {
// end of file/data
if (empty($info['mpeg']['audio'])) {
$info['error'][] = 'could not find valid MPEG synch before end of file';
if (isset($info['audio']['bitrate'])) {
unset($info['audio']['bitrate']);
}
if (isset($info['mpeg']['audio'])) {
unset($info['mpeg']['audio']);
}
if (isset($info['mpeg']) && (!is_array($info['mpeg']) || empty($info['mpeg']))) {
unset($info['mpeg']);
}
return false;
}
break;
}
}
$info['audio']['channels'] = $info['mpeg']['audio']['channels'];
$info['audio']['channelmode'] = $info['mpeg']['audio']['channelmode'];
$info['audio']['sample_rate'] = $info['mpeg']['audio']['sample_rate'];
return true;
}
/**
* @param type $BlockData
*
* @return bool
*/
private function parseSEEKTABLE($BlockData)
{
$info =& $this->getid3->info;
$offset = 0;
$BlockLength = strlen($BlockData);
$placeholderpattern = str_repeat("ÿ", 8);
while ($offset < $BlockLength) {
$SampleNumberString = substr($BlockData, $offset, 8);
$offset += 8;
if ($SampleNumberString == $placeholderpattern) {
// placeholder point
Helper::safe_inc($info['flac']['SEEKTABLE']['placeholders'], 1);
$offset += 10;
} else {
$SampleNumber = Helper::BigEndian2Int($SampleNumberString);
$info['flac']['SEEKTABLE'][$SampleNumber]['offset'] = Helper::BigEndian2Int(substr($BlockData, $offset, 8));
$offset += 8;
$info['flac']['SEEKTABLE'][$SampleNumber]['samples'] = Helper::BigEndian2Int(substr($BlockData, $offset, 2));
$offset += 2;
}
}
return true;
}
/**
* @return bool
*/
public function analyze()
{
$info =& $this->getid3->info;
$OriginalAVdataOffset = $info['avdataoffset'];
fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
$VOCheader = fread($this->getid3->fp, 26);
$magic = 'Creative Voice File';
if (substr($VOCheader, 0, 19) != $magic) {
$info['error'][] = 'Expecting "' . Helper::PrintHexBytes($magic) . '" at offset ' . $info['avdataoffset'] . ', found "' . Helper::PrintHexBytes(substr($VOCheader, 0, 19)) . '"';
return false;
}
// shortcuts
$thisfile_audio =& $info['audio'];
$info['voc'] = array();
$thisfile_voc =& $info['voc'];
$info['fileformat'] = 'voc';
$thisfile_audio['dataformat'] = 'voc';
$thisfile_audio['bitrate_mode'] = 'cbr';
$thisfile_audio['lossless'] = true;
$thisfile_audio['channels'] = 1;
// might be overriden below
$thisfile_audio['bits_per_sample'] = 8;
// might be overriden below
// byte # Description
// ------ ------------------------------------------
// 00-12 'Creative Voice File'
// 13 1A (eof to abort printing of file)
// 14-15 Offset of first datablock in .voc file (std 1A 00 in Intel Notation)
// 16-17 Version number (minor,major) (VOC-HDR puts 0A 01)
// 18-19 2's Comp of Ver. # + 1234h (VOC-HDR puts 29 11)
$thisfile_voc['header']['datablock_offset'] = Helper::LittleEndian2Int(substr($VOCheader, 20, 2));
$thisfile_voc['header']['minor_version'] = Helper::LittleEndian2Int(substr($VOCheader, 22, 1));
$thisfile_voc['header']['major_version'] = Helper::LittleEndian2Int(substr($VOCheader, 23, 1));
do {
$BlockOffset = ftell($this->getid3->fp);
$BlockData = fread($this->getid3->fp, 4);
$BlockType = ord($BlockData[0]);
$BlockSize = Helper::LittleEndian2Int(substr($BlockData, 1, 3));
$ThisBlock = array();
Helper::safe_inc($thisfile_voc['blocktypes'][$BlockType], 1);
switch ($BlockType) {
case 0:
// Terminator
// do nothing, we'll break out of the loop down below
break;
case 1:
// Sound data
$BlockData .= fread($this->getid3->fp, 2);
if ($info['avdataoffset'] <= $OriginalAVdataOffset) {
$info['avdataoffset'] = ftell($this->getid3->fp);
}
fseek($this->getid3->fp, $BlockSize - 2, SEEK_CUR);
$ThisBlock['sample_rate_id'] = Helper::LittleEndian2Int(substr($BlockData, 4, 1));
$ThisBlock['compression_type'] = Helper::LittleEndian2Int(substr($BlockData, 5, 1));
$ThisBlock['compression_name'] = $this->VOCcompressionTypeLookup($ThisBlock['compression_type']);
if ($ThisBlock['compression_type'] <= 3) {
$thisfile_voc['compressed_bits_per_sample'] = Helper::CastAsInt(str_replace('-bit', '', $ThisBlock['compression_name']));
}
// Less accurate sample_rate calculation than the Extended block (#8) data (but better than nothing if Extended Block is not available)
if (empty($thisfile_audio['sample_rate'])) {
// SR byte = 256 - (1000000 / sample_rate)
$thisfile_audio['sample_rate'] = Helper::trunc(1000000 / (256 - $ThisBlock['sample_rate_id']) / $thisfile_audio['channels']);
}
break;
case 2:
// Sound continue
// Sound continue
case 3:
// Silence
// Silence
case 4:
// Marker
// Marker
case 6:
// Repeat
// Repeat
case 7:
// End repeat
// nothing useful, just skip
fseek($this->getid3->fp, $BlockSize, SEEK_CUR);
break;
case 8:
// Extended
$BlockData .= fread($this->getid3->fp, 4);
//00-01 Time Constant:
// Mono: 65536 - (256000000 / sample_rate)
// Stereo: 65536 - (256000000 / (sample_rate * 2))
$ThisBlock['time_constant'] = Helper::LittleEndian2Int(substr($BlockData, 4, 2));
$ThisBlock['pack_method'] = Helper::LittleEndian2Int(substr($BlockData, 6, 1));
$ThisBlock['stereo'] = (bool) Helper::LittleEndian2Int(substr($BlockData, 7, 1));
$thisfile_audio['channels'] = $ThisBlock['stereo'] ? 2 : 1;
$thisfile_audio['sample_rate'] = Helper::trunc(256000000 / (65536 - $ThisBlock['time_constant']) / $thisfile_audio['channels']);
break;
case 9:
// data block that supersedes blocks 1 and 8. Used for stereo, 16 bit
$BlockData .= fread($this->getid3->fp, 12);
if ($info['avdataoffset'] <= $OriginalAVdataOffset) {
$info['avdataoffset'] = ftell($this->getid3->fp);
}
fseek($this->getid3->fp, $BlockSize - 12, SEEK_CUR);
$ThisBlock['sample_rate'] = Helper::LittleEndian2Int(substr($BlockData, 4, 4));
$ThisBlock['bits_per_sample'] = Helper::LittleEndian2Int(substr($BlockData, 8, 1));
$ThisBlock['channels'] = Helper::LittleEndian2Int(substr($BlockData, 9, 1));
$ThisBlock['wFormat'] = Helper::LittleEndian2Int(substr($BlockData, 10, 2));
$ThisBlock['compression_name'] = $this->VOCwFormatLookup($ThisBlock['wFormat']);
if ($this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat'])) {
$thisfile_voc['compressed_bits_per_sample'] = $this->VOCwFormatActualBitsPerSampleLookup($ThisBlock['wFormat']);
}
$thisfile_audio['sample_rate'] = $ThisBlock['sample_rate'];
$thisfile_audio['bits_per_sample'] = $ThisBlock['bits_per_sample'];
$thisfile_audio['channels'] = $ThisBlock['channels'];
break;
default:
$info['warning'][] = 'Unhandled block type "' . $BlockType . '" at offset ' . $BlockOffset;
fseek($this->getid3->fp, $BlockSize, SEEK_CUR);
break;
}
if (!empty($ThisBlock)) {
$ThisBlock['block_offset'] = $BlockOffset;
$ThisBlock['block_size'] = $BlockSize;
$ThisBlock['block_type_id'] = $BlockType;
$thisfile_voc['blocks'][] = $ThisBlock;
}
} while (!feof($this->getid3->fp) && $BlockType != 0);
// Terminator block doesn't have size field, so seek back 3 spaces
fseek($this->getid3->fp, -3, SEEK_CUR);
ksort($thisfile_voc['blocktypes']);
if (!empty($thisfile_voc['compressed_bits_per_sample'])) {
$info['playtime_seconds'] = ($info['avdataend'] - $info['avdataoffset']) * 8 / ($thisfile_voc['compressed_bits_per_sample'] * $thisfile_audio['channels'] * $thisfile_audio['sample_rate']);
$thisfile_audio['bitrate'] = ($info['avdataend'] - $info['avdataoffset']) * 8 / $info['playtime_seconds'];
}
return true;
}
/**
* @staticvar array $decbin
*
* @param type $MaxFramesToScan
* @param type $ReturnExtendedInfo
*
* @return bool
*/
public function getAACADTSheaderFilepointer($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
$BitrateCache = array();
while (true) {
// breaks out when end-of-file encountered, or invalid data found,
// or MaxFramesToScan frames have been scanned
if (!Helper::intValueSupported($byteoffset)) {
$info['warning'][] = 'Unable to parse AAC file beyond ' . ftell($this->getid3->fp) . ' (PHP does not support file operations beyond ' . round(PHP_INT_MAX / 1073741824) . 'GB)';
return false;
}
fseek($this->getid3->fp, $byteoffset, SEEK_SET);
// First get substring
$substring = fread($this->getid3->fp, 9);
// header is 7 bytes (or 9 if CRC is present)
$substringlength = strlen($substring);
if ($substringlength != 9) {
$info['error'][] = 'Failed to read 7 bytes at offset ' . (ftell($this->getid3->fp) - $substringlength) . ' (only read ' . $substringlength . ' bytes)';
return false;
}
// this would be easier with 64-bit math, but split it up to allow for 32-bit:
$header1 = Helper::BigEndian2Int(substr($substring, 0, 2));
$header2 = Helper::BigEndian2Int(substr($substring, 2, 4));
$header3 = Helper::BigEndian2Int(substr($substring, 6, 1));
$info['aac']['header']['raw']['syncword'] = ($header1 & 0xfff0) >> 4;
if ($info['aac']['header']['raw']['syncword'] != 0xfff) {
$info['error'][] = 'Synch pattern (0x0FFF) not found at offset ' . (ftell($this->getid3->fp) - $substringlength) . ' (found 0x0' . strtoupper(dechex($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 & 0x8) >> 3;
$info['aac']['header']['raw']['mpeg_layer'] = ($header1 & 0x6) >> 1;
$info['aac']['header']['raw']['protection_absent'] = ($header1 & 0x1) >> 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 & 0x2000000) >> 25;
$info['aac']['header']['raw']['channels_code'] = ($header2 & 0x1c00000) >> 22;
$info['aac']['header']['raw']['original'] = ($header2 & 0x200000) >> 21;
$info['aac']['header']['raw']['home'] = ($header2 & 0x100000) >> 20;
$info['aac']['header']['raw']['copyright_stream'] = ($header2 & 0x80000) >> 19;
$info['aac']['header']['raw']['copyright_start'] = ($header2 & 0x40000) >> 18;
$info['aac']['header']['raw']['frame_length'] = ($header2 & 0x3ffe0) >> 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) {
$info['warning'][] = 'Layer error - expected "0", found "' . $info['aac']['header']['raw']['mpeg_layer'] . '" instead';
}
if ($info['aac']['header']['sample_frequency'] == 0) {
$info['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 & 0x3ffe0) >> 5;
if (!isset($BitrateCache[$FrameLength])) {
$BitrateCache[$FrameLength] = $info['aac']['header']['sample_frequency'] / 1024 * $FrameLength * 8;
}
Helper::safe_inc($info['aac']['bitrate_distribution'][$BitrateCache[$FrameLength]], 1);
$info['aac'][$framenumber]['aac_frame_length'] = $FrameLength;
$info['aac'][$framenumber]['adts_buffer_fullness'] = ($header2 & 0x1f) << 6 & ($header3 & 0xfc) >> 2;
if ($info['aac'][$framenumber]['adts_buffer_fullness'] == 0x7ff) {
$info['audio']['bitrate_mode'] = 'vbr';
} else {
$info['audio']['bitrate_mode'] = 'cbr';
}
$info['aac'][$framenumber]['num_raw_data_blocks'] = ($header3 & 0x3) >> 0;
if ($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) {
$info['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.
}