cron/transcoder.php : support use of ffmpeg (over libav)

cron/transcoder.php

@@ -1,10 +1,38 @@
 <?php
 
-require_once __DIR__ . '/../config.php';
+/**
+ * Older versions of XOT allowed LO authors to upload .flv videos for embedding with the Learning Object.
+ * Unfortunately, flv videos aren't compatible with HTML5 based templates and will not display on e.g. tablets as
+ * Adobe Flash is not available. 
+ * This cron job, when run will look for all videos which do not have an '.mp4' extension, and attempt to transcode (i.e. reformat) them.
+ * the original file is left as is - so if you start with :
+ *
+ * USER-FILES/2-Test-Nottingham/media/something.flv
+ * 
+ * you'll end up with :
+ *
+ * USER-FILES/2-Test-Nottingham/media/something.flv
+ * USER-FILES/2-Test-Nottingham/media/something.mp4
+ *  
+ * When the script runs it looks to see if a .mp4 variant of the file already exists, and if it does, it does nothing.
+ *
+ * Note, depending on your media files, running this may consume quite a lot of CPU / disk resource.
+ * No 'intelligence' is included to cope with duplicated source media files - to reduce resource usage.
+ *
+ *
+ * You'll need to have something like 'avconv' or 'ffmpeg' installed. See comments inline below.
+ * It'll probably work best with ffmpeg. Perhaps.
+ *
+ */
+require_once dirname(__FILE__) . '/../config.php';
+
+if(!is_file('/usr/bin/avconv') && !is_File('/usr/bin/ffmpeg')) {
+    die("Cannot run; /usr/bin/avconv or /usr/bin/ffmpeg does not appear to be present");
+}
 
 $finfo = new finfo(FILEINFO_MIME_TYPE);
-$files = glob($xerte_toolkits_site->users_file_area_full . '*/media/*');
 
+$files = glob($xerte_toolkits_site->users_file_area_full . '*/media/*');
 
 foreach ($files as $filename) {
 
@@ -31,16 +59,21 @@ function add_transcode_job($inputFilename, $outputFilename)
 {   
     // Ubuntu 14.04 - libav-tools, libavcodec-extra-54
 
-    $cmd = 'avconv '
-        . '-i ' . escapeshellarg($inputFilename)    // input filename
-        . ' -c:v h264 '                             // video codec
-        . '-b:v 2000k '                             // video bitrate
-        . '-c:a aac '                               // audio codec
-        . '-b:a 196k '                              // audio bitrate
-        . '-f mp4 '                                 // file format
-        . '-strict experimental '                   // enable aac codec
-        . escapeshellarg($outputFilename)           // output filename
-        . ' 2>&1';
+    if(is_file('/usr/bin/ffmpeg')) {
+        $cmd = 'ffmpeg -i ' . escapeshellarg($inputFilename) . ' -sameq -ar 22050 -vcodec libx264  ' . escapeshellarg($outputFilename) . ' 2>&1' ;
+    }
+    else {
+        $cmd = 'avconv '
+            . '-i ' . escapeshellarg($inputFilename)    // input filename
+            . ' -c:v h264 '                             // video codec
+            . '-b:v 2000k '                             // video bitrate
+            . '-c:a aac '                               // audio codec
+            . '-b:a 196k '                              // audio bitrate
+            . '-f mp4 '                                 // file format
+            . '-strict experimental '                   // enable aac codec
+            . escapeshellarg($outputFilename)           // output filename
+            . ' 2>&1';
+    }
 
     _debug("Running: $cmd");