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clean up frame extraction code

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This commit is contained in:
ccd0 2013-11-30 02:07:05 -08:00
parent 2175e84834
commit 14ac1b562d
2 changed files with 105 additions and 18 deletions
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34
matroska.php
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@ -9,6 +9,7 @@ class EBMLElementType {
// Information needed to parse all possible element types in a document
class EBMLElementTypeList {
private $_els;
private $_ids;
public function __construct($filename) {
$lines = file($filename);
@ -27,6 +28,7 @@ class EBMLElementTypeList {
}
}
$this->_els[$id] = $t;
$this->_ids[strtoupper($t->name)] = $id;
}
}
@ -39,6 +41,12 @@ class EBMLElementTypeList {
return $this->_els[$id]->name;
}
public function id($name) {
$name = strtoupper($name);
if (!isset($this->_ids[$name])) return NULL;
return $this->_ids[$name];
}
public function datatype($id) {
if ($id == 'root') return 'container';
if (!isset($this->_els[$id])) return 'binary';
@ -379,7 +387,7 @@ class EBMLElementList extends EBMLElement implements Iterator {
foreach ($this as $element) {
$iElement++;
if ($iElement > self::$MAX_ELEMENTS) throw new Exception('not supported: too many elements');
if ($element->name() == $name) {
if (strtoupper($element->name()) == strtoupper($name)) {
return $element->value();
}
}
@ -488,3 +496,27 @@ function readMatroska($fileHandle) {
}
return $root;
}
function encodeVarInt($n) {
$data = '';
$flag = 0x80;
while ($n >= $flag) {
if ($flag == 0) {
throw new Exception('not supported: number too large');
}
$data = chr($n & 0xFF) . $data;
$n = $n >> 8;
$flag = $flag >> 1;
}
$data = chr($n | $flag) . $data;
return $data;
}
function encodeElementName($name) {
global $EBML_ELEMENTS;
return encodeVarInt($EBML_ELEMENTS->id($name));
}
function encodeElement($name, $content) {
return encodeElementName($name) . encodeVarInt(strlen($content)) . $content;
}

89
videodata.php
View File

@ -1,22 +1,77 @@
<?php
require dirname(__FILE__) . '/matroska.php';
// Header for single VPx keyframe
function vpxFrameHeader($size, $width, $height, $codecID) {
return "\x1A\x45\xDF\xA3\x9F\x42\x86\x81\x01\x42\xF7\x81\x01\x42\xF2\x81"
. "\x04\x42\xF3\x81\x08\x42\x82\x84\x77\x65\x62\x6D\x42\x87\x81\x02"
. "\x42\x85\x81\x02\x18\x53\x80\x67\x08" . pack('N', $size + 173) . "\x11\x4D\x9B"
. "\x74\xB8\x4D\xBB\x8B\x53\xAB\x84\x15\x49\xA9\x66\x53\xAC\x81\x3D"
. "\x4D\xBB\x8B\x53\xAB\x84\x16\x54\xAE\x6B\x53\xAC\x81\x58\x4D\xBB"
. "\x8B\x53\xAB\x84\x1C\x53\xBB\x6B\x53\xAC\x81\x85\x4D\xBB\x8B\x53"
. "\xAB\x84\x1F\x43\xB6\x75\x53\xAC\x81\x97\x15\x49\xA9\x66\x96\x2A"
. "\xD7\xB1\x83\x0F\x42\x40\x44\x89\x84\x41\x20\x00\x00\x4D\x80\x81"
. "\x66\x57\x41\x81\x66\x16\x54\xAE\x6B\xA8\xAE\xA6\xD7\x81\x01\x73"
. "\xC5\x81\x01\x83\x81\x01\x23\xE3\x83\x83\x98\x96\x80\x86\x85" . $codecID
. "\xE0\x8C\xB0\x84" . pack('N', $width) . "\xBA\x84" . pack('N', $height)
. "\x1C\x53\xBB\x6B\x8D\xBB\x8B\xB3\x81\x00\xB7\x86\xF7\x81"
. "\x01\xF1\x81\x97\x1F\x43\xB6\x75\x08" . pack('N', $size + 13) . "\xE7\x81\x00"
. "\xA3\x08" . pack('N', $size + 4) . "\x81\x00\x00\x80";
// Make video from single VPx keyframe
function muxVPxFrame($width, $height, $codecID, $data) {
$size = strlen($data);
$lenSeekHead = 61;
$lenCues = 18;
$ebml = encodeElement('EBML',
encodeElement('EBMLVersion', "\x01")
. encodeElement('EBMLReadVersion', "\x01")
. encodeElement('EBMLMaxIDLength', "\x04")
. encodeElement('EBMLMaxSizeLength', "\x08")
. encodeElement('DocType', "webm")
. encodeElement('DocTypeVersion', "\x02")
. encodeElement('DocTypeReadVersion', "\x02")
);
$info = encodeElement('Info',
encodeElement('TimecodeScale', "\x0F\x42\x40")
. encodeElement('Duration', "\x41\x20\x00\x00")
. encodeElement('MuxingApp', 'f')
. encodeElement('WritingApp', 'f')
);
$tracks = encodeElement('Tracks',
encodeElement('TrackEntry',
encodeElement('TrackNumber', "\x01")
. encodeElement('TrackUID', "\x01")
. encodeElement('TrackType', "\x01")
. encodeElement('DefaultDuration', "\x98\x96\x80")
. encodeElement('CodecID', $codecID)
. encodeElement('Video',
encodeElement('PixelWidth', pack('N', $width))
. encodeElement('PixelHeight', pack('N', $height))
)
)
);
$cues = encodeElement('Cues',
encodeElement('CuePoint',
encodeElement('CueTime', "\x00")
. encodeElement('CueTrackPositions',
encodeElement('CueTrack', "\x01")
. encodeElement('CueClusterPosition', chr($lenSeekHead + strlen($info) + strlen($tracks) + $lenCues))
)
)
);
$seekHead = encodeElement('SeekHead',
encodeElement('Seek',
encodeElement('SeekID', encodeElementName('Info'))
. encodeElement('SeekPosition', chr($lenSeekHead))
)
. encodeElement('Seek',
encodeElement('SeekID', encodeElementName('Tracks'))
. encodeElement('SeekPosition', chr($lenSeekHead + strlen($info)))
)
. encodeElement('Seek',
encodeElement('SeekID', encodeElementName('Cues'))
. encodeElement('SeekPosition', chr($lenSeekHead + strlen($info) + strlen($tracks)))
)
. encodeElement('Seek',
encodeElement('SeekID', encodeElementName('Cluster'))
. encodeElement('SeekPosition', chr($lenSeekHead + strlen($info) + strlen($tracks) + $lenCues))
)
);
$cluster = "\x1F\x43\xB6\x75\x08" . pack('N', $size + 13) . (
//. encodeElement('Cluster',
encodeElement('Timecode', "\x00")
. "\xA3\x08" . pack('N', $size + 4) . ("\x81\x00\x00\x80" . $data)
//. encodeElement('SimpleBlock', "\x81\x00\x00\x80" . $data)
);
$segment = "\x18\x53\x80\x67\x08" . pack('N', $size + 173) . (
// . encodeElement('Segment',
$seekHead . $info . $tracks . $cues . $cluster
);
return $ebml . $segment;
}
// Locate first VPx keyframe of track $trackNumber after timecode $skip
@ -120,7 +175,7 @@ function videoData($filename) {
}
$frame = firstVPxFrame($segment, $trackNumber, $skip);
if (!isset($frame)) throw new Exception('no keyframes');
$data['frame'] = vpxFrameHeader($frame->size(), $pixelWidth, $pixelHeight, $codecID) . $frame->readAll();
$data['frame'] = muxVPxFrame($pixelWidth, $pixelHeight, $codecID, $frame->readAll());
} catch (Exception $e) {
error_log($e->getMessage());