Merge branch 'master' of github.com:vichan-devel/Tinyboard into br-integration

1 files changed, 173 insertions, 0 deletions

diff --git a/inc/lib/webm/videodata.php b/inc/lib/webm/videodata.php
new file mode 100644
index 00000000..d54d484b
--- /dev/null
+++ b/inc/lib/webm/videodata.php
@@ -0,0 +1,173 @@
+<?php
+/* This file is dedicated to the public domain; you may do as you wish with it. */
+require dirname(__FILE__) . '/matroska.php';
+
+function matroskaSeekElement($name, $pos) {
+    return ebmlEncodeElement('Seek',
+        ebmlEncodeElement('SeekID', ebmlEncodeElementName($name))
+        . ebmlEncodeElement('SeekPosition', pack('N', $pos))
+    );
+}
+
+// Make video from single WebM keyframe
+function muxWebMFrame($videoTrack, $frame) {
+    $lenSeekHead = 73;
+    $lenCues = 24;
+
+    // Determine version for EBML header
+    $version = 2;
+    $videoAttr = $videoTrack->get('Video');
+    if (isset($videoAttr)) {
+        if ($videoAttr->get('StereoMode') !== NULL) $version = 3;
+        if ($videoAttr->get('AlphaMode') !== NULL) $version = 3;
+    }
+    if ($videoTrack->get('CodecDelay') !== NULL) $version = 4;
+    if ($videoTrack->get('SeekPreRoll') !== NULL) $version = 4;
+    if ($frame->name() == 'BlockGroup' && $frame->get('DiscardPadding') !== NULL) $version = 4;
+
+    // EBML header
+    $ebml = ebmlEncodeElement('EBML',
+        ebmlEncodeElement('DocType', "webm")
+        . ebmlEncodeElement('DocTypeVersion', chr($version))
+        . ebmlEncodeElement('DocTypeReadVersion', "\x02")
+    );
+
+    // Segment
+    $info = ebmlEncodeElement('Info',
+        ebmlEncodeElement('Duration', "\x41\x20\x00\x00")
+        . ebmlEncodeElement('MuxingApp', 'ccframe')
+        . ebmlEncodeElement('WritingApp', 'ccframe')
+    );
+    $tracks = ebmlEncodeElement('Tracks',
+        ebmlEncodeElement('TrackEntry', $videoTrack->content()->readAll())
+    );
+    $cues = ebmlEncodeElement('Cues',
+        ebmlEncodeElement('CuePoint',
+            ebmlEncodeElement('CueTime', "\x00")
+            . ebmlEncodeElement('CueTrackPositions',
+                ebmlEncodeElement('CueTrack', pack('N', $videoTrack->get('TrackNumber')))
+                . ebmlEncodeElement('CueClusterPosition', pack('N', $lenSeekHead + strlen($info) + strlen($tracks) + $lenCues))
+            )
+        )
+    );
+    if (strlen($cues) != $lenCues) throw new Exception('length of Cues element wrong');
+    $cluster = ebmlEncodeElement('Cluster',
+        ebmlEncodeElement('Timecode', "\x00")
+        . ebmlEncodeElement($frame->name(), $frame->content()->readAll())
+        . ebmlEncodeElement('Void', '')
+    );
+    $seekHead = ebmlEncodeElement('SeekHead',
+        matroskaSeekElement('Info', $lenSeekHead)
+        . matroskaSeekElement('Tracks', $lenSeekHead + strlen($info))
+        . matroskaSeekElement('Cues', $lenSeekHead + strlen($info) + strlen($tracks))
+        . matroskaSeekElement('Cluster', $lenSeekHead + strlen($info) + strlen($tracks) + $lenCues)
+    );
+    if (strlen($seekHead) != $lenSeekHead) throw new Exception('length of SeekHead element wrong');
+    $segment = ebmlEncodeElement('Segment', $seekHead . $info . $tracks . $cues . $cluster);
+
+    return $ebml . $segment;
+}
+
+// Locate first WebM keyframe of track $trackNumber after timecode $skip
+function firstWebMFrame($segment, $trackNumber, $skip=0) {
+    foreach($segment as $x1) {
+        if ($x1->name() == 'Cluster') {
+            $cluserTimecode = $x1->Get('Timecode');
+            foreach($x1 as $blockGroup) {
+                $blockRaw = NULL;
+                if ($blockGroup->name() == 'SimpleBlock') {
+                    $blockRaw = $blockGroup->value();
+                } elseif ($blockGroup->name() == 'BlockGroup') {
+                    $blockRaw = $blockGroup->get('Block');
+                }
+                if (isset($blockRaw)) {
+                    $block = new MatroskaBlock($blockRaw);
+                    if ($block->trackNumber == $trackNumber && $block->keyframe) {
+                        if (!isset($cluserTimecode) || $cluserTimecode + $block->timecode >= $skip) {
+                            return $blockGroup;
+                        } elseif (!isset($frame1)) {
+                            $frame1 = $blockGroup;
+                        }
+                    }
+                }
+            }
+        }
+    }
+    return isset($frame1) ? $frame1 : NULL;
+}
+
+function videoData($filename) {
+    $data = array();
+
+    // Open file
+    $fileHandle = fopen($filename, 'rb');
+    if (!$fileHandle) {
+        error_log('could not open file');
+        return $data;
+    }
+
+    try {
+        $root = readMatroska($fileHandle);
+        $data['container'] = $root->get('EBML')->get('DocType');
+
+        // Locate segment information and tracks
+        $segment = $root->get('Segment');
+        if (!isset($segment)) throw new Exception('missing Segment element');
+
+        // Get segment information
+        $info = $segment->get('Info');
+        if (isset($info)) {
+            $timecodeScale = $info->get('TimecodeScale');
+            $duration = $info->get('Duration');
+            if (isset($timecodeScale) && isset($duration)) {
+                $data['duration'] = 1e-9 * $timecodeScale * $duration;
+            }
+        }
+
+        // Locate video track
+        $tracks = $segment->get('Tracks');
+        if (!isset($tracks)) throw new Exception('missing Tracks element');
+        foreach($tracks as $trackEntry) {
+            if ($trackEntry->name() == 'TrackEntry' && $trackEntry->get('TrackType') == 1) {
+                $videoTrack = $trackEntry;
+                break;
+            }
+        }
+        if (!isset($videoTrack)) throw new Exception('no video track');
+
+        // Get track information
+        $videoAttr = $videoTrack->get('Video');
+        if (!isset($videoAttr)) throw new Exception('missing video parameters');
+        $pixelWidth = $videoAttr->get('PixelWidth');
+        $pixelHeight = $videoAttr->get('PixelHeight');
+        if (!isset($pixelWidth) || !isset($pixelHeight)) throw new Exception('no width or height');
+        if ($pixelWidth == 0 || $pixelHeight == 0) throw new Exception('bad PixelWidth/PixelHeight');
+        $displayWidth = $videoAttr->get('DisplayWidth', $pixelWidth);
+        $displayHeight = $videoAttr->get('DisplayHeight', $pixelHeight);
+        if ($displayWidth == 0 || $displayHeight == 0) throw new Exception('bad DisplayWidth/DisplayHeight');
+        $data['width'] = $displayWidth;
+        $data['height'] = $displayHeight;
+
+        // Extract frame to use as thumbnail
+        if ($videoAttr->get('AlphaMode') != NULL) {
+            if (!($pixelWidth % 2 == 0 && $pixelHeight % 2 == 0 && $displayWidth % 2 == 0 && $displayHeight % 2 == 0)) {
+                throw new Exception('preview frame blocked due to Chromium bug');
+            }
+        }
+        $trackNumber = $videoTrack->get('TrackNumber');
+        if (!isset($trackNumber)) throw new Exception('missing track number');
+        if (isset($data['duration']) && $data['duration'] >= 5) {
+            $skip = 1e9 / $timecodeScale;
+        } else {
+            $skip = 0;
+        }
+        $frame = firstWebMFrame($segment, $trackNumber, $skip);
+        if (!isset($frame)) throw new Exception('no keyframes');
+        $data['frame'] = muxWebMFrame($videoTrack, $frame);
+    } catch (Exception $e) {
+        error_log($e->getMessage());
+    }
+
+    fclose($fileHandle);
+    return $data;
+}