1 files changed, 131 insertions, 0 deletions
diff --git a/videodata.php b/videodata.php
new file mode 100644
index 00000000..3fe9eeee
--- /dev/null
+++ b/videodata.php
@@ -0,0 +1,131 @@
+<?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";
+}
+
+// Locate first VPx keyframe of track $trackNumber after timecode $skip
+function firstVPxFrame($segment, $trackNumber, $skip=0) {
+    foreach($segment as $x1) {
+        if ($x1->name() == 'Cluster') {
+            $cluserTimecode = $x1->Get('Timecode');
+            foreach($x1 as $x2) {
+                $blockRaw = NULL;
+                if ($x2->name() == 'SimpleBlock') {
+                    $blockRaw = $x2->value();
+                } elseif ($x2->name() == 'BlockGroup') {
+                    $blockRaw = $x2->get('Block');
+                }
+                if (isset($blockRaw)) {
+                    $block = new MatroskaBlock($blockRaw);
+                    if ($block->trackNumber == $trackNumber) {
+                        $frame = $block->frames[0];
+                        if ($block->keyframe) {
+                            if (!isset($cluserTimecode) || $cluserTimecode + $block->timecode >= $skip) {
+                                return $frame;
+                            } elseif (!isset($frame1)) {
+                                $frame1 = $frame;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    return isset($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);
+
+        // 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)) {
+            $pixelWidth = $videoAttr->get('PixelWidth');
+            $pixelHeight = $videoAttr->get('PixelHeight');
+            if ($pixelWidth == 0 || $pixelHeight == 0) {
+                error_log('bad PixelWidth/PixelHeight');
+                $pixelWidth = NULL;
+                $pixelHeight = NULL;
+            }
+            $data['width'] = $videoAttr->get('DisplayWidth', $pixelWidth);
+            $data['height'] = $videoAttr->get('DisplayHeight', $pixelHeight);
+            if ($data['width'] == 0 || $data['height'] == 0) {
+                error_log('bad DisplayWidth/DisplayHeight');
+                $data['width'] = $pixelWidth;
+                $data['height'] = $pixelHeight;
+            }
+        }
+
+        // Extract frame to use as thumbnail
+        $trackNumber = $videoTrack->get('TrackNumber');
+        if (!isset($trackNumber)) throw new Exception('missing track number');
+        $codecID = $videoTrack->get('CodecID');
+        if ($codecID != 'V_VP8' && $codecID != 'V_VP9') throw new Exception('codec is not VP8 or VP9');
+        if (!isset($pixelWidth) || !isset($pixelHeight)) throw new Exception('no width or height');
+        if (isset($data['duration']) && $data['duration'] >= 5) {
+            $skip = 1e9 / $timecodeScale;
+        } else {
+            $skip = 0;
+        }
+        $frame = firstVPxFrame($segment, $trackNumber, $skip);
+        if (!isset($frame)) throw new Exception('no keyframes');
+        $data['frame'] = vpxFrameHeader($frame->size(), $pixelWidth, $pixelHeight, $codecID) . $frame->readAll();
+
+    } catch (Exception $e) {
+        error_log($e->getMessage());
+    }
+
+    fclose($fileHandle);
+    return $data;
+}