Turn returned HTTP headers lowercase before parsing

NGINX for some reason returns "content-length" instead of
"Content-Length".

src/Mp3FileRemote.php

@@ -2,6 +2,8 @@
 
 namespace wapmorgan\Mp3Info;
 
+use \Exception;
+
 class Mp3FileRemote
 {
     public string $fileName;
@@ -50,7 +52,8 @@ class Mp3FileRemote
             ],
         ]);
         $result = get_headers($this->fileName, true, $context);
-        return $result['Content-Length'];
+        $result = array_change_key_case($result, CASE_LOWER);
+        return $result['content-length'];
     }
 
     /**
@@ -68,7 +71,10 @@ class Mp3FileRemote
         $output = [];
         
         do {
-            $this->downloadBlock($blockId);   // make sure we have this block
+            // make sure we have this block
+            if (!$this->downloadBlock($blockId)) {
+                throw new Exception('Error downloading block ' . $blockId . ' (starting at pos. ' . ($blockId * $this->blockSize) . ')!');
+            }   
             if ($blockPos + $numBytes >= $this->blockSize) {
                 // length of request is more than this block has, truncate to block len
                 $subLen = $this->blockSize - $blockPos;
@@ -152,6 +158,9 @@ class Mp3FileRemote
             ],
         ]);
         $filePtr = fopen($this->fileName, 'rb', false, $context);
+        if ($filePtr === false) {
+            return false;
+        }
         $this->buffer[$blockNo] = fread($filePtr, $this->blockSize);
         $status = stream_get_meta_data($filePtr);
         $httpStatus = explode(' ', $status['wrapper_data'][0])[1];

src/Mp3Info.php

@@ -29,7 +29,8 @@ use \RuntimeException;
  * * {@link https://multimedia.cx/mp3extensions.txt Descripion of VBR header "Xing"}
  * * {@link http://gabriel.mp3-tech.org/mp3infotag.html Xing, Info and Lame tags specifications}
  */
-class Mp3Info {
+class Mp3Info
+{
     const TAG1_SYNC = 'TAG';
     const TAG2_SYNC = 'ID3';
     const VBR_SYNC = 'Xing';
@@ -77,6 +78,15 @@ class Mp3Info {
         self::MPEG_2 => [13, 21],
         self::MPEG_25 => [13, 21],
     ];
+    
+    /**
+     * @var array
+     */
+    private static $_id3v2HeaderFlags = [
+        2 => ['unsynchronisation', 'compression'],
+        3 => ['unsynchronisation', 'extended_header', 'experimental_indicator'],
+        4 => ['unsynchronisation', 'extended_header', 'experimental_indicator', 'footer_present'],
+    ];
 
     /**
      * @var int Limit in bytes for seeking a mpeg header in file
@@ -120,6 +130,31 @@ class Mp3Info {
      */
     public $sampleRate;
 
+    /**
+     * @var bool Header protection by 16 bit CRC
+     */
+    public $isProtected;
+
+    /**
+     * @var bool Frame data is padded with one slot
+     */
+    public $isPadded;
+
+    /**
+     * @var bool Private bit (only informative)
+     */
+    public $isPrivate;
+
+    /**
+     * @var bool Copyright bit (only informative)
+     */
+    public $isCopyright;
+
+    /**
+     * @var bool Original bit (only informative)
+     */
+    public $isOriginal;
+
     /**
      * @var boolean Contains true if audio has variable bit rate
      */
@@ -164,17 +199,20 @@ class Mp3Info {
     /**
      * @var int Major version of id3v2 tag (if id3v2  present) (2 or 3 or 4)
      */
-    public $id3v2MajorVersion;
+    public $id3v2MajorVersion;   // @deprecated
+    public $id3v2Version;
 
     /**
      * @var int Minor version of id3v2 tag (if id3v2 present)
      */
-    public $id3v2MinorVersion;
+    public $id3v2MinorVersion;   // @deprecated
+    public $id3v2Revision;
 
     /**
      * @var array List of id3v2 header flags (if id3v2 present)
      */
     public $id3v2Flags = [];
+    public $id3v2HeaderFlags = [];
 
     /**
      * @var array List of id3v2 tags flags (if id3v2 present)
@@ -222,15 +260,17 @@ class Mp3Info {
     public function __construct(string $filename, bool $parseTags = false)
     {
         if (self::$_bitRateTable === null)
-            self::$_bitRateTable = require dirname(__FILE__).'/../data/bitRateTable.php';
+            self::$_bitRateTable = require __DIR__.'/../data/bitRateTable.php';
         if (self::$_sampleRateTable === null)
-            self::$_sampleRateTable = require dirname(__FILE__).'/../data/sampleRateTable.php';
+            self::$_sampleRateTable = require __DIR__.'/../data/sampleRateTable.php';
 
+        $this->_fileName = $filename;
         if (str_contains($filename, '://')) {
             $this->fileObj = new Mp3FileRemote($filename);
         } else {
             $this->fileObj = new Mp3FileLocal($filename);
         }
+        $this->_fileSize = $this->fileObj->getFileSize();
 
         $mode = $parseTags ? self::META | self::TAGS : self::META;
         $this->audioSize = $this->parseAudio($mode);
@@ -253,6 +293,13 @@ class Mp3Info {
         return $data;
     }
 
+    protected function getSynchsafeSize(string $rawBytes): int
+    {
+        $sizeBytes = unpack('C4', $rawBytes);
+        $size = $sizeBytes[1] << 21 | $sizeBytes[2] << 14 | $sizeBytes[3] << 7 | $sizeBytes[4];
+        return $size;
+    }
+
     /**
      * Reads audio file in binary mode.
      * mpeg audio file structure:
@@ -263,30 +310,36 @@ class Mp3Info {
      * @return float|int
      * @throws \Exception
      */
-    private function parseAudio($mode) {
+    private function parseAudio($mode)
+    {
         $time = microtime(true);
 
         /** @var int Size of audio data (exclude tags size) */
         $audioSize = $this->fileObj->getFileSize();
 
-        // parse tags
+        // try ID3v2 parsing
+        $audioSize -= ($this->_id3Size = $this->_parseId3v2Header(!($mode & self::TAGS)));
+
+        /*/ parse tags
         if ($this->fileObj->getBytes(3) == self::TAG2_SYNC) {
             if ($mode & self::TAGS) {
                 $audioSize -= ($this->_id3Size = $this->readId3v2Body());
             } else {
-                $this->fileObj->seekForward(2); // 2 bytes of tag version
+                $this->fileObj->seekForward(2); // 2 bytes of tag version+revision
                 $this->fileObj->seekForward(1); // 1 byte of tag flags
-                $sizeBytes = unpack('C4', $this->fileObj->getBytes(4));
-                $size = $sizeBytes[1] << 21 | $sizeBytes[2] << 14 | $sizeBytes[3] << 7 | $sizeBytes[4];
+                $size = $this->getSynchsafeSize($this->fileObj->getBytes(4));
                 $size += 10;   // add header size
                 $audioSize -= ($this->_id3Size = $size);
             }
-        }
+        }*/
 
         $this->fileObj->seekTo($this->fileObj->getFileSize() - 128);
         if ($this->fileObj->getBytes(3) == self::TAG1_SYNC) {
-            if ($mode & self::TAGS) $audioSize -= $this->readId3v1Body($fp);
-            else $audioSize -= 128;
+            if ($mode & self::TAGS) {
+                $audioSize -= $this->_readId3v1();
+            } else {
+                $audioSize -= 128;
+            }
         }
 
         if ($mode & self::TAGS) {
@@ -303,7 +356,7 @@ class Mp3Info {
              * Read first N frames
              */
             for ($i = 0; $i < self::$framesCountRead; $i++) {
-                $framesCount = $this->readMpegFrame();
+                $framesCount = $this->_readMpegFrame();
             }
 
             $this->_framesCount = $framesCount !== null
@@ -331,59 +384,58 @@ class Mp3Info {
         return $audioSize;
     }
 
+    private function _findNextMpegFrame(int $headerSeekLimit): ?string
+    {
+        // find frame sync
+        $headerSeekMax = $this->fileObj->getFilePos() + $headerSeekLimit;
+        $headerBytes = $this->fileObj->getBytes(3);   // preload with 3 Bytes
+        do {
+            $headerBytes .= $this->fileObj->getBytes(1);   // load next Byte
+            $headerBytes = substr($headerBytes, -4);   // limit to 4 Bytes
+
+            if ((unpack('n', $headerBytes)[1] & self::FRAME_SYNC) === self::FRAME_SYNC) {
+                return $headerBytes;
+            }
+        } while ($this->fileObj->getFilePos() <= $headerSeekMax);
+ 
+        return null;
+    }
+
     /**
      * Read first frame information.
+     *
+     * @link   https://www.codeproject.com/Articles/8295/MPEG-Audio-Frame-Header
      * @return int Number of frames (if present if first frame of VBR-file)
      * @throws \Exception
      */
-    private function readMpegFrame() {
-        $header_seek_pos = $this->fileObj->getFilePos() + self::$headerSeekLimit;
-        do {
-            $pos = $this->fileObj->getFilePos();
-            $first_header_byte = $this->fileObj->getBytes(1);
-            if (ord($first_header_byte[0]) === 0xFF) {
-                $second_header_byte = $this->fileObj->getBytes(1);
-                if (((ord($second_header_byte[0]) >> 5) & 0b111) == 0b111) {
-                    $this->fileObj->seekTo($pos);
-                    $header_bytes = $this->fileObj->getBytes(4);
-                    break;
-                } else {
-                    $this->fileObj->seekForward(-1);
-                }
-            } else {
-                $this->fileObj->seekForward(-1);
-            }
-            $this->fileObj->seekForward(1);
-        } while ($this->fileObj->getFilePos() <= $header_seek_pos);
-
-        if (!isset($header_bytes) || ord($header_bytes[0]) !== 0xFF || ((ord($header_bytes[1]) >> 5) & 0b111) != 0b111) {
-            throw new \Exception('At '.$pos
-                .'(0x'.dechex($pos).') should be a frame header!');
+    private function _readMpegFrame()
+    {
+        $headerBytes = $this->_findNextMpegFrame(self::$headerSeekLimit);
+        $pos = $this->fileObj->getFilePos() - 4;
+        if (is_null($headerBytes)) {
+            throw new Exception('No Mpeg frame header found up until pos ' . $pos . '(0x' . dechex($pos) . ')!');
         }
 
-        switch (ord($header_bytes[1]) >> 3 & 0b11) {
-            case 0b00: $this->codecVersion = self::MPEG_25; break;
-            case 0b01: return null; break;
-            case 0b10: $this->codecVersion = self::MPEG_2; break;
-            case 0b11: $this->codecVersion = self::MPEG_1; break;
-        }
+        // 2nd Byte: (rest of frame sync), Version, Layer, Protection
+        $this->codecVersion = [self::MPEG_25, null, self::MPEG_2, self::MPEG_1][ord($headerBytes[1]) >> 3 & 0b11];
+        $this->layerVersion = [null, self::LAYER_3, self::LAYER_2, self::LAYER_1][ord($headerBytes[1]) >> 1 & 0b11];
+        $this->isProtected = !((ord($headerBytes[1]) & 0b1) == 0b1);   // inverted as 0=protected, 1=not protected
 
-        switch (ord($header_bytes[1]) >> 1 & 0b11) {
-            case 0b01: $this->layerVersion = self::LAYER_3; break;
-            case 0b10: $this->layerVersion = self::LAYER_2; break;
-            case 0b11: $this->layerVersion = self::LAYER_1; break;
+        // 3rd Byte: Bitrate, Sampling rate, Padding, Private
+        $this->bitRate = self::$_bitRateTable[$this->codecVersion][$this->layerVersion][ord($headerBytes[2]) >> 4];
+        $this->sampleRate = self::$_sampleRateTable[$this->codecVersion][(ord($headerBytes[2]) >> 2) & 0b11];
+        if ($this->sampleRate === false) {
+            return null;
         }
+        $this->isPadded = ((ord($headerBytes[2]) & 0b10) == 0b10);
+        $this->isPrivate = ((ord($headerBytes[2]) & 0b1) == 0b1);
 
-        $this->bitRate = self::$_bitRateTable[$this->codecVersion][$this->layerVersion][ord($header_bytes[2]) >> 4];
-        $this->sampleRate = self::$_sampleRateTable[$this->codecVersion][(ord($header_bytes[2]) >> 2) & 0b11];
-        if ($this->sampleRate === false) return null;
-
-        switch (ord($header_bytes[3]) >> 6) {
-            case 0b00: $this->channel = self::STEREO; break;
-            case 0b01: $this->channel = self::JOINT_STEREO; break;
-            case 0b10: $this->channel = self::DUAL_MONO; break;
-            case 0b11: $this->channel = self::MONO; break;
-        }
+        // 4th Byte: Channels, Mode extension, Copyright, Original, Emphasis
+        $this->channel = [self::STEREO, self::JOINT_STEREO, self::DUAL_MONO, self::MONO][ord($headerBytes[3]) >> 6];
+        // TODO: Mode extension (2 bits)
+        $this->isCopyright = ((ord($headerBytes[3]) & 0b1000) == 0b1000);
+        $this->isOriginal  = ((ord($headerBytes[3]) & 0b100) == 0b100);
+        // TODO: Emphasis (2 bits)
 
         $vbr_offset = self::$_vbrOffsets[$this->codecVersion][$this->channel == self::MONO ? 0 : 1];
 
@@ -413,151 +465,143 @@ class Mp3Info {
 
         // go to the end of frame
         if ($this->layerVersion == self::LAYER_1) {
-            $this->_cbrFrameSize = floor((12 * $this->bitRate / $this->sampleRate + (ord($header_bytes[2]) >> 1 & 0b1)) * 4);
+            $this->_cbrFrameSize = floor((12 * $this->bitRate / $this->sampleRate + (ord($headerBytes[2]) >> 1 & 0b1)) * 4);
         } else {
-            $this->_cbrFrameSize = floor(144 * $this->bitRate / $this->sampleRate + (ord($header_bytes[2]) >> 1 & 0b1));
+            $this->_cbrFrameSize = floor(144 * $this->bitRate / $this->sampleRate + (ord($headerBytes[2]) >> 1 & 0b1));
         }
 
         $this->fileObj->seekTo($pos + $this->_cbrFrameSize);
 
-        return isset($this->vbrProperties['frames']) ? $this->vbrProperties['frames'] : null;
+        return $this->vbrProperties['frames'] ?? null;
     }
 
     /**
      * Reads id3v1 tag.
+     *
+     * @link   https://id3.org/ID3v1
      * @return int Returns length of id3v1 tag.
      */
-    private function readId3v1Body() {
-        $this->tags1['song'] = trim($this->fileObj->getBytes(30));
+    private function _readId3v1(): int
+    {
+        $this->tags1['song']   = trim($this->fileObj->getBytes(30));
         $this->tags1['artist'] = trim($this->fileObj->getBytes(30));
-        $this->tags1['album'] = trim($this->fileObj->getBytes(30));
-        $this->tags1['year'] = trim($this->fileObj->getBytes(4));
-        $this->tags1['comment'] = trim($this->fileObj->getBytes(28));
-        $this->fileObj->seekForward(1);
-        $this->tags1['track'] = ord($this->fileObj->getBytes(1));
-        $this->tags1['genre'] = ord($this->fileObj->getBytes(1));
+        $this->tags1['album']  = trim($this->fileObj->getBytes(30));
+        $this->tags1['year']   = trim($this->fileObj->getBytes(4));
+        $comment = $this->fileObj->getBytes(30);
+        if ($comment[28] == "\x00" && $comment[29] != "\x00") {
+            // id3v1.1 - last Byte of comment is trackNo
+            $this->tags1['track']   = ord($comment[29]);
+            $this->tags1['comment'] = trim(substr($comment, 0, 28));
+        } else {
+            // id3v1.0
+            $this->tags1['comment'] = trim($comment);
+        }
+        $this->tags1['genre'] = '(' . ord($this->fileObj->getBytes(1)) . ')';
         return 128;
     }
+    
+    private function _parseId3v2Flags(int $version, int $flags): array
+    {
+        $result = array();
+        if ($version >= 2) {
+            // parse id3v2.2.0 header flags
+            $result['unsynchronisation'] = ($flags & 128 == 128);
+            $result['compression'] = ($flags & 64 == 64);
+        }
+        
+        if ($version >= 3) {
+            // id3v2.3 changes second bit from compression to extended_header
+            $result['extended_header'] = &$result['compression'];
+            unset($result['compression']);
+            // parse additional id3v2.3.0 header flags
+            $result['experimental_indicator'] = ($flags & 32 == 32);
+
+        }
+
+        if ($version >= 4) {
+            // parse additional id3v2.4.0 header flags
+            $result['footer_present'] = ($flags & 16 == 16);
+        }
+        return $result;
+    }
 
     /**
-     * Reads id3v2 tag.
-     * -----------------------------------
-     * Overall tag header structure (10 bytes)
-     *  ID3v2/file identifier      "ID3" (3 bytes)
-     *  ID3v2 version              (2 bytes)
-     *  ID3v2 flags                (1 byte)
-     *  ID3v2 size             4 * %0xxxxxxx (4 bytes)
-     * -----------------------------------
-     * id3v2.2.0 tag header (10 bytes)
-     *  ID3/file identifier      "ID3" (3 bytes)
-     *  ID3 version              $02 00 (2 bytes)
-     *  ID3 flags                %xx000000 (1 byte)
-     *  ID3 size             4 * %0xxxxxxx (4 bytes)
-     * Flags:
-     *  x (bit 7) - unsynchronisation
-     *  x (bit 6) - compression
-     * -----------------------------------
-     * id3v2.3.0 tag header (10 bytes)
-     *  ID3v2/file identifier   "ID3" (3 bytes)
-     *  ID3v2 version           $03 00 (2 bytes)
-     *  ID3v2 flags             %abc00000 (1 byte)
-     *  ID3v2 size              4 * %0xxxxxxx (4 bytes)
-     * Flags:
-     *  a - Unsynchronisation
-     *  b - Extended header
-     *  c - Experimental indicator
-     * Extended header structure (10 bytes)
-     *  Extended header size   $xx xx xx xx
-     *  Extended Flags         $xx xx
-     *  Size of padding        $xx xx xx xx
-     * Extended flags:
-     *  %x0000000 00000000
-     *  x - CRC data present
-     * -----------------------------------
-     * id3v2.4.0 tag header (10 bytes)
-     *  ID3v2/file identifier      "ID3" (3 bytes)
-     *  ID3v2 version              $04 00 (2 bytes)
-     *  ID3v2 flags                %abcd0000 (1 byte)
-     *  ID3v2 size             4 * %0xxxxxxx (4 bytes)
-     * Flags:
-     *  a - Unsynchronisation
-     *  b - Extended header
-     *  c - Experimental indicator
-     *  d - Footer present
-     * @param resource $fp
-     * @return int Returns length of id3v2 tag.
-     * @throws \Exception
+     * Reads ID3v2 header and returns the ID3v2 tag size. 0 if no header was found.
+     *
+     * @param bool $sizeOnly Only parse ID3v2 size
+     * 
+     * @return int Size of ID3v2 struct
      */
-    private function readId3v2Body()
+    private function _parseId3v2Header(bool $sizeOnly = true): int
     {
-        // read the rest of the id3v2 header
-        $raw = $this->fileObj->getBytes(7);
-        $data = unpack('cmajor_version/cminor_version/H*', $raw);
-        $this->id3v2MajorVersion = $data['major_version'];
-        $this->id3v2MinorVersion = $data['minor_version'];
-        $data = str_pad(base_convert($data[1], 16, 2), 40, 0, STR_PAD_LEFT);
-        $flags = substr($data, 0, 8);
-        if ($this->id3v2MajorVersion == 2) { // parse id3v2.2.0 header flags
-            $this->id3v2Flags = array(
-                'unsynchronisation' => (bool)substr($flags, 0, 1),
-                'compression' => (bool)substr($flags, 1, 1),
-            );
-        } else if ($this->id3v2MajorVersion == 3) { // parse id3v2.3.0 header flags
-            $this->id3v2Flags = array(
-                'unsynchronisation' => (bool)substr($flags, 0, 1),
-                'extended_header' => (bool)substr($flags, 1, 1),
-                'experimental_indicator' => (bool)substr($flags, 2, 1),
-            );
-            if ($this->id3v2Flags['extended_header'])
-                throw new \Exception('NEED TO PARSE EXTENDED HEADER!');
-        } else if ($this->id3v2MajorVersion == 4) { // parse id3v2.4.0 header flags
-            $this->id3v2Flags = array(
-                'unsynchronisation' => (bool)substr($flags, 0, 1),
-                'extended_header' => (bool)substr($flags, 1, 1),
-                'experimental_indicator' => (bool)substr($flags, 2, 1),
-                'footer_present' => (bool)substr($flags, 3, 1),
-            );
-            if ($this->id3v2Flags['extended_header'])
-                throw new \Exception('NEED TO PARSE EXTENDED HEADER!');
-            if ($this->id3v2Flags['footer_present'])
-                throw new \Exception('NEED TO PARSE id3v2.4 FOOTER!');
+        // check for "ID3" marker
+        if ($this->fileObj->getBytes(3) != self::TAG2_SYNC) {
+            // No ID3V2 tag found
+            return 0;
         }
-        $size = substr($data, 8, 32);
+        
+        $headerSize = 10;
+        $footerSize = 0;
 
-        // some fucking shit
-        // getting only 7 of 8 bits of size bytes
-        $sizes = str_split($size, 8);
-        array_walk($sizes, function (&$value) {
-            $value = substr($value, 1);
-        });
-        $size = implode($sizes);
-        $size = bindec($size);
+        // read the rest of the id3v2 header
+        $raw = $this->fileObj->getBytes(3);
+        $size = $this->getSynchsafeSize($this->fileObj->getBytes(4));
+        if ($sizeOnly) {
+            // just return the size
+            // NOTE: $footerSize unclear at this point, might be inaccurate
+            return $headerSize + $footerSize + $size;
+        }
 
-        if ($this->id3v2MajorVersion == 2) {
+        // parse version and flags
+        $data = unpack('Cversion/Crevision/Cflags', $raw);
+        $this->id3v2Version = $data['version'];
+        $this->id3v2Revision = $data['revision'];
+        // backwards compatibility:
+        $this->id3v2MajorVersion = $data['version'];
+        $this->id3v2MinorVersion = $data['revision'];
+
+        $flagsList = self::$_id3v2HeaderFlags[$this->id3v2Version];
+        // TODO: CONTINUE HERE - PARSE DIFFERENTLY
+        $this->id3v2Flags = $this->_parseId3v2Flags($this->id3v2Version, $data['flags']);
+
+        if ($this->id3v2Flags['extended_header']) {
+            throw new Exception('NEED TO PARSE EXTENDED HEADER!');
+        }
+
+        if ($this->id3v2Flags['footer_present']) {
+            // footer is a copy of header - so can be ignored
+            // (10 Bytes not included in $size)
+            $footerSize = 10;
+        }
+
+        // Now parse the frames
+        if ($this->id3v2Version == 2) {
             // parse id3v2.2.0 body
             /*throw new \Exception('NEED TO PARSE id3v2.2.0 flags!');*/
-        } else if ($this->id3v2MajorVersion == 3) {
+        } elseif ($this->id3v2Version == 3) {
             // parse id3v2.3.0 body
             $this->parseId3v23Body(10 + $size);
-        } else if ($this->id3v2MajorVersion == 4)  {
+        } elseif ($this->id3v2Version == 4) {
             // parse id3v2.4.0 body
             $this->parseId3v24Body(10 + $size);
         }
 
-        return 10 + $size; // 10 bytes - header, rest - body
+        return $headerSize + $footerSize + $size;
     }
 
     /**
      * Parses id3v2.3.0 tag body.
      * @todo Complete.
      */
-    protected function parseId3v23Body($lastByte) {
+    protected function parseId3v23Body($lastByte)
+    {
+        // TODO: Change $lastByte into $payloadLength so it works independent of starting location
         while ($this->fileObj->getFilePos() < $lastByte) {
             $raw = $this->fileObj->getBytes(10);
             $frame_id = substr($raw, 0, 4);
 
             if ($frame_id == str_repeat(chr(0), 4)) {
-                fseek($fp, $lastByte);
+                $this->fileObj->seekTo($lastByte);
                 break;
             }
 
@@ -565,6 +609,7 @@ class Mp3Info {
             $frame_size = $data['frame_size'];
             $flags = base_convert($data['flags'], 16, 2);
             $this->id3v2TagsFlags[$frame_id] = array(
+                'payload_size' => $frame_size,
                 'flags' => array(
                     'tag_alter_preservation' => (bool)substr($flags, 0, 1),
                     'file_alter_preservation' => (bool)substr($flags, 1, 1),
@@ -697,15 +742,15 @@ class Mp3Info {
                 //     break;
                  case 'APIC':    # Attached picture
                      $this->hasCover = true;
-                     $last_byte = $this->fileObj->getFilePos() + $frame_size;
+                     $dataEnd = $this->fileObj->getFilePos() + $frame_size;
                      $this->coverProperties = ['text_encoding' => ord($this->fileObj->getBytes(1))];
 //                     fseek($fp, $frame_size - 4, SEEK_CUR);
-                     $this->coverProperties['mime_type'] = $this->readTextUntilNull($last_byte);
+                     $this->coverProperties['mime_type'] = $this->readTextUntilNull($dataEnd);
                      $this->coverProperties['picture_type'] = ord($this->fileObj->getBytes(1));
-                     $this->coverProperties['description'] = $this->readTextUntilNull($last_byte);
+                     $this->coverProperties['description'] = $this->readTextUntilNull($dataEnd);
                      $this->coverProperties['offset'] = $this->fileObj->getFilePos();
-                     $this->coverProperties['size'] = $last_byte - $this->fileObj->getFilePos();
-                     $this->fileObj->seekTo($last_byte);
+                     $this->coverProperties['size'] = $dataEnd - $this->fileObj->getFilePos();
+                     $this->fileObj->seekTo($dataEnd);
                      break;
                 // case 'GEOB':    # General encapsulated object
                 //     break;
@@ -744,24 +789,26 @@ class Mp3Info {
 
     /**
      * Parses id3v2.4.0 tag body.
-     * @param $fp
+     *
      * @param $lastByte
      */
     protected function parseId3v24Body($lastByte)
     {
+        // TODO: Change $lastByte into $payloadLength so it works independent of starting location
         while ($this->fileObj->getFilePos() < $lastByte) {
-            $raw = $this->fileObj->getBytes(10);
-            $frame_id = substr($raw, 0, 4);
+            $frame_id = $this->fileObj->getBytes(4);
 
             if ($frame_id == str_repeat(chr(0), 4)) {
                 $this->fileObj->seekTo($lastByte);
                 break;
             }
 
-            $data = unpack('Nframe_size/H2flags', substr($raw, 4));
-            $frame_size = $data['frame_size'];
+            $frame_size = $this->getSynchsafeSize($this->fileObj->getBytes(4));
+
+            $data = unpack('H2flags', $this->fileObj->getBytes(2));
             $flags = base_convert($data['flags'], 16, 2);
             $this->id3v2TagsFlags[$frame_id] = array(
+                'payload_size' => $frame_size,
                 'flags' => array(
                     'tag_alter_preservation' => (bool)substr($flags, 1, 1),
                     'file_alter_preservation' => (bool)substr($flags, 2, 1),
@@ -782,7 +829,6 @@ class Mp3Info {
                 case 'TALB':    # Album/Movie/Show title
                 case 'TCON':    # Content type
                 case 'TYER':    # Year
-                case 'TXXX':    # User defined text information frame
                 case 'TRCK':    # Track number/Position in set
                 case 'TIT2':    # Title/songname/content description
                 case 'TPE1':    # Lead performer(s)/Soloist(s)
@@ -790,6 +836,7 @@ class Mp3Info {
                 case 'TCOM':    # Composer
                 case 'TCOP':    # Copyright message
                 case 'TDAT':    # Date
+                case 'TDRC':    # Recording time
                 case 'TDLY':    # Playlist delay
                 case 'TENC':    # Encoded by
                 case 'TEXT':    # Lyricist/Text writer
@@ -821,6 +868,24 @@ class Mp3Info {
                     $this->tags2[$frame_id] = $this->handleTextFrame($frame_size, $this->fileObj->getBytes($frame_size));
                     break;
 
+                case 'TXXX':    # User defined text information frame
+                    $dataEnd = $this->fileObj->getFilePos() + $frame_size;
+                    $encoding = ord($this->fileObj->getBytes(1));
+                    $description_raw = $this->readTextUntilNull($dataEnd);
+                    $description = $this->_getUtf8Text($encoding, $description_raw);
+                    $value = $this->fileObj->getBytes($dataEnd - $this->fileObj->getFilePos());
+                    $tagName = $frame_id . ':' . $description;
+                    if (key_exists($tagName, $this->tags2)) {
+                        // this should never happen! TXXX-description must be unique.
+                        if (!is_array($this->tags2[$tagName])) {
+                            $this->tags2[$tagName] = array($this->tags2[$tagName]);
+                        }
+                        $this->tags2[$tagName][] = $value;
+                    } else {
+                        $this->tags2[$tagName] = $value;
+                    }
+                    break;
+
                 ################# Text information frames
 
                 ################# URL link frames
@@ -860,33 +925,16 @@ class Mp3Info {
                 //     break;
                 case 'COMM':    # Comments
                     $dataEnd = $this->fileObj->getFilePos() + $frame_size;
-                    $raw = $this->fileObj->getBytes(4);
-                    $data = unpack('C1encoding/A3language', $raw);
-                    // read until \null character
-                    $short_description = null;
-                    $last_null = false;
-                    $actual_text = false;
-                    while ($this->fileObj->getFilePos() < $dataEnd) {
-                        $char = fgetc($fp);
-                        if ($char == "\00" && $actual_text === false) {
-                            if ($data['encoding'] == 0x1) { # two null-bytes for utf-16
-                                if ($last_null)
-                                    $actual_text = null;
-                                else
-                                    $last_null = true;
-                            } else # no condition for iso-8859-1
-                                $actual_text = null;
+                    $encoding = unpack('C', $this->fileObj->getBytes(1))[1];
+                    $language = $this->fileObj->getBytes(3);
+                    $allText_raw = $this->fileObj->getBytes($dataEnd - $this->fileObj->getFilePos());
+                    $allText = $this->_getUtf8Text($encoding, $allText_raw);
 
-                        }
-                        else if ($actual_text !== false) $actual_text .= $char;
-                        else $short_description .= $char;
-                    }
-                    if ($actual_text === false) $actual_text = $short_description;
-                    // list($short_description, $actual_text) = sscanf("s".chr(0)."s", $data['texts']);
-                    // list($short_description, $actual_text) = explode(chr(0), $data['texts']);
-                    $this->tags2[$frame_id][$data['language']] = array(
-                        'short' => (bool)($data['encoding'] == 0x00) ? mb_convert_encoding($short_description, 'utf-8', 'iso-8859-1') : mb_convert_encoding($short_description, 'utf-8', 'utf-16'),
-                        'actual' => (bool)($data['encoding'] == 0x00) ? mb_convert_encoding($actual_text, 'utf-8', 'iso-8859-1') : mb_convert_encoding($actual_text, 'utf-8', 'utf-16'),
+                    list($short_description, $actual_text) = explode("\0", $allText, 2);
+
+                    $this->tags2[$frame_id][$language] = array(
+                        'short' => $short_description,
+                        'actual' => $actual_text,
                     );
                     break;
                 // case 'RVAD':    # Relative volume adjustment
@@ -897,15 +945,15 @@ class Mp3Info {
                 //     break;
                 case 'APIC':    # Attached picture
                     $this->hasCover = true;
-                    $last_byte = $this->fileObj->getFilePos() + $frame_size;
+                    $dataEnd = $this->fileObj->getFilePos() + $frame_size;
                     $this->coverProperties = ['text_encoding' => ord($this->fileObj->getBytes(1))];
 //                     $this->fileObj->seekForward($frame_size - 4);
-                    $this->coverProperties['mime_type'] = $this->readTextUntilNull($fp, $last_byte);
+                    $this->coverProperties['mime_type'] = $this->readTextUntilNull($dataEnd);
                     $this->coverProperties['picture_type'] = ord($this->fileObj->getBytes(1));
-                    $this->coverProperties['description'] = $this->readTextUntilNull($fp, $last_byte);
+                    $this->coverProperties['description'] = $this->readTextUntilNull($dataEnd);
                     $this->coverProperties['offset'] = $this->fileObj->getFilePos();
-                    $this->coverProperties['size'] = $last_byte - $this->fileObj->getFilePos();
-                    $this->fileObj->seekTo($last_byte);
+                    $this->coverProperties['size'] = $dataEnd - $this->fileObj->getFilePos();
+                    $this->fileObj->seekTo($dataEnd);
                     break;
                 // case 'GEOB':    # General encapsulated object
                 //     break;
@@ -942,6 +990,38 @@ class Mp3Info {
         }
     }
 
+    /**
+     * Converts text encoding according to ID3 indicator
+     *
+     * @param int    $encoding Encoding ID from ID3 frame
+     * @param string $rawText  Raw text from ID3 frame
+     *
+     * @return string
+     */
+    private function _getUtf8Text(int $encoding, ?string $rawText): string
+    {
+        if (is_null($rawText)) {
+            $rawText = '';
+        }
+        
+        switch ($encoding) {
+            case 0x00:   // ISO-8859-1
+                return mb_convert_encoding($rawText, 'utf-8', 'iso-8859-1');
+
+            case 0x01:   // UTF-16 with BOM
+                return mb_convert_encoding($rawText . "\00", 'utf-8', 'utf-16');
+
+            // Following is for id3v2.4.x only
+            case 0x02:   // UTF-16 without BOM
+                return mb_convert_encoding($rawText . "\00", 'utf-8', 'utf-16');
+            case 0x03:   // UTF-8
+                return $rawText;
+
+            default:
+                throw new RuntimeException('Unknown text encoding type: ' . $encoding);
+        }
+    }
+
     /**
      * @param $frameSize
      * @param $raw
@@ -951,22 +1031,7 @@ class Mp3Info {
     private function handleTextFrame($frameSize, $raw)
     {
         $data = unpack('C1encoding/A' . ($frameSize - 1) . 'information', $raw);
-
-        switch($data['encoding']) {
-            case 0x00: # ISO-8859-1
-                return mb_convert_encoding($data['information'], 'utf-8', 'iso-8859-1');
-            case 0x01: # utf-16 with BOM
-                return mb_convert_encoding($data['information'] . "\00", 'utf-8', 'utf-16');
-
-            # Following is for id3v2.4.x only
-            case 0x02: # utf-16 without BOM
-                return mb_convert_encoding($data['information'] . "\00", 'utf-8', 'utf-16');
-            case 0x03: # utf-8
-                return $data['information'];
-
-            default:
-                throw new RuntimeException('Unknown text encoding type: '.$data['encoding']);
-        }
+        return $this->_getUtf8Text($data['encoding'], $data['information']);
     }
 
     /**
@@ -1020,7 +1085,8 @@ class Mp3Info {
      * @return boolean True if file looks that correct mpeg audio, False otherwise.
      * @throws \Exception
      */
-    public static function isValidAudio($filename) {
+    public static function isValidAudio($filename)
+    {
         if (str_contains($filename, '://')) {
             $fileObj = new Mp3FileRemote($filename);
         } else {
@@ -1037,7 +1103,7 @@ class Mp3Info {
             // id3v2 tag
             return true;
         }
-        if (self::FRAME_SYNC === (unpack('n*', $raw)[1] & self::FRAME_SYNC)) {
+        if ((unpack('n', $raw)[1] & self::FRAME_SYNC) === self::FRAME_SYNC) {
             // mpeg header tag
             return true;
         }
@@ -1050,4 +1116,4 @@ class Mp3Info {
         }
         return false;
     }
-}
+}