wip
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194b0fc284
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cbae496cf8
1 changed files with 118 additions and 48 deletions
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@ -401,6 +401,8 @@ class MP3FrameHeader {
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public $valid = false;
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public $size = 0;
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public $samples = 0;
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public $duration = 0.0;
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public $sync;
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public $mpeg;
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@ -428,6 +430,33 @@ class MP3FrameHeader {
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private const SYNC_MASK = 0x7ff;
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private static $versions = [
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'MPEG-2.5',
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'reserved',
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'MPEG-2',
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'MPEG-1',
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];
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private static $layers = [
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'reserved',
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'III',
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'II',
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'I',
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];
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private static $samplesPerFrame = [
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// invalid / layer 3 / 2 / 1
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// MPEG-2.5
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[ 0, 576, 1152, 384 ],
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// Reserved
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[ 0, 0, 0, 0 ],
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// MPEG-2
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[ 0, 576, 1152, 384 ],
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// MPEG-1
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[ 0, 1152, 384, 384 ],
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];
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// 1s used for reserved slots to avoid exploding
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// in case of invalid input
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private static $sampleRates = [
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@ -442,9 +471,9 @@ class MP3FrameHeader {
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];
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private static $bitrates = [
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// MPEG-2
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[
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// MPEG-2
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// invalid
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// invalid layer
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[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ],
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// layer 3
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[ 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0 ],
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@ -453,9 +482,9 @@ class MP3FrameHeader {
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// layer 1
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[ 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0 ],
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],
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// MPEG-1
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[
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// MPEG-1
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// invalid
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// invalid layer
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[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ],
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// layer 3
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[ 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 192, 224, 256, 320, 0 ],
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@ -475,31 +504,47 @@ class MP3FrameHeader {
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public function __construct( $header ) {
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$this->header = $header;
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$this->sync = $this->field( 'sync' ) == self::SYNC_MASK;
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$sync = $this->field( 'sync' );
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$this->sync = $sync == self::SYNC_MASK;
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if ( $this->sync ) {
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$this->mpeg = $this->field( 'mpeg' );
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$this->layer = $this->field( 'layer' );
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$this->protection = $this->field( 'protection' );
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$mpeg = $this->field( 'mpeg' );
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$this->mpeg = self::$versions[$mpeg];
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$layer = $this->field( 'layer' );
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$this->layer = self::$layers[$layer];
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$protection = $this->field( 'protection' );
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$this->protection = !$protection;
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$br = $this->field( 'bitrate' );
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$this->bitrate = 1000 * self::$bitrates[$this->mpeg & 1][$this->layer][$br];
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$this->bitrate = 1000 * self::$bitrates[$mpeg & 1][$layer][$br];
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$sr = $this->field( 'sampleRate' );
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$this->sampleRate = self::$sampleRates[$this->mpeg][$sr];
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$this->sampleRate = self::$sampleRates[$mpeg][$sr];
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$this->padding = $this->field( 'padding' );
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$this->valid = $this->sync;
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if ( $this->bitrate == 0 ) {
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var_dump( $this );
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echo "br: $br\n";
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//throw new Exception( "Invalid bitrate" );
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$this->valid = false;
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if ( $this->sync ) {
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if ( $this->bitrate == 0 ) {
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$this->valid = false;
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var_dump( $this );
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echo "br: $br\n";
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throw new Exception( "Invalid bitrate" );
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}
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if ( $this->sampleRate == 1 ) {
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$this->valid = false;
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var_dump( $this );
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echo "sr: $sr\n";
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throw new Exception( "Invalid sample rate" );
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}
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$this->valid = true;
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}
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if ( $this->sampleRate == 1 ) {
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var_dump( $this );
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echo "sr: $sr\n";
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//throw new Exception( "Invalid sample rate" );
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$this->valid = false;
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}
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$this->size = intval( 144.0 * $this->bitrate / $this->sampleRate );
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$this->samples = self::$samplesPerFrame[$mpeg][$layer];
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$this->duration = $this->samples / $this->sampleRate;
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$nbits = $this->duration * $this->bitrate;
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$nbytes = $nbits / 8;
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$this->size = intval( $nbytes );
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if ( $this->protection ) {
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$this->size += 2;
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}
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@ -513,6 +558,7 @@ class MP3FrameHeader {
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class MP3Reader {
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private $file;
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private $timestamp = 0.0;
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public function __construct( $file ) {
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$this->file = $file;
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@ -524,33 +570,60 @@ class MP3Reader {
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public function readFrame() {
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while ( true ) {
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// Look for the sync pattern
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$start = $this->pos();
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$bytes = fread( $this->file, 4 );
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if ( $bytes === false || strlen( $bytes ) < 4 ) {
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$lookahead = 10;
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$bytes = fread( $this->file, $lookahead );
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if ( $bytes === false || strlen( $bytes ) < $lookahead ) {
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// end of file
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return false;
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}
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// Check for MP3 frame header sync pattern
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$data = unpack( "Nval", $bytes );
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$header = new MP3FrameHeader( $data['val'] );
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if ( $header->valid ) {
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if ( $header->sync ) {
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$segments[] = [
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'start' => $start,
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'size' => $header->size,
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'timestamp' => $this->timestamp,
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'duration' => $header->duration,
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];
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$this->timestamp += $header->duration;
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// Note we don't need the data at this time.
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//fseek( $this->file, $start + $header->size, SEEK_SET );
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var_dump ( $header );
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fread( $this->file, $header->size - 4 );
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return $header;
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fseek( $this->file, $start + $header->size, SEEK_SET );
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continue;
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}
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$x = hexdump( $bytes );
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print "BACKUP $x\n";
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if ( $header->sync && !$header->valid ) {
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$x = hexdump( $bytes );
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die('xxx ' . $x);
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// ID3v2.3
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// https://web.archive.org/web/20081008034714/http://www.id3.org/id3v2.3.0
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// ID3v2/file identifier "ID3"
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// ID3v2 version $03 00
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// ID3v2 flags %abc00000
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// ID3v2 size 4 * %0xxxxxxx
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$id3 = unpack( "a3tag/nversion/Cflags/C4size", $bytes );
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if ( $id3['tag'] === 'ID3' ) {
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$size = $lookahead +
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( $id3['size4'] |
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( $id3['size3'] << 7) |
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( $id3['size2'] << 14) |
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( $id3['size1'] << 21) );
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// For byte range purposes; count as zero duration
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$segments[] = [
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'start' => $start,
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'size' => $size,
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'timestamp' => $this->timestamp,
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'duration' => 0.0,
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];
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fseek( $this->file, $start + $size, SEEK_SET );
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continue;
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}
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$hex = hexdump( $bytes );
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$safe = safestr ( $bytes );
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var_dump($segments);
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throw new Exception("Invalid packet at $start? $hex $safe");
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// back up 3 bytes and try again
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// back up and try again
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fseek( $this->file, $start + 1, SEEK_SET );
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}
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}
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@ -567,19 +640,13 @@ function extractMP3( $filename ) {
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$timestamp = 0.0;
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while ( true ) {
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$start = $reader->pos();
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$frame = $reader->readFrame();
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if ( !$frame ) {
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$segment = $reader->readFrame();
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if ( !$segment ) {
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return $segments;
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}
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$duration = 144.0 / $frame->sampleRate;
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$segments[] = [
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'start' => $start,
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'size' => $frame->size,
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'timestamp' => $timestamp,
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'duration' => $duration,
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];
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$timestamp += $duration;
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$segments[] = $segment;
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}
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return $segments;
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} finally {
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fclose( $file );
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}
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@ -590,6 +657,9 @@ function consolidate( $target, $segments ) {
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if ( isset( $segments['init'] ) ) {
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$out['init'] = $segments['init'];
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}
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if ( count( $segments ) < 2 ) {
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return $segments;
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}
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$n = count( $segments ) - 1;
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$start = $segments[0]['start'];
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