ffmpeg doesn't always return false when it fails - here's how to catch it

[richardpickett]

As the title states, ffmpeg doesn't always return false when it fails, this patch below is to put a filesize() check in place to make sure the thumbnail was actually created.

Not having this check in place causes the entire import to fail with a stacktrace whenever the synchronize is performed and ffmpeg can't generate a thumbnail from a mp4.

Having this check in place allows processing to continue, with the failed thumbnail noted in the "error" section of the results page.

# diff -u piwigo-videojs-master/include/function_sync2.php function_sync2.php 
--- piwigo-videojs-master/include/function_sync2.php    2022-08-15 13:29:40.000000000 -0500
+++ function_sync2.php  2023-03-01 11:55:02.646411728 -0600
@@ -188,7 +188,7 @@
                 //echo $ffmpeg;
                 $log = system($ffmpeg, $retval);
                 //$infos[] = $filename. ' poster : retval:'. $retval. ", log:". print_r($log, True);
-                if($retval != 0 or !file_exists($out))
+                if($retval != 0 or !file_exists($out) or !filesize($out))
                 {
                     $errors[] = "Error poster running ffmpeg/avconv, try it manually, check your webserver error log:\n<br/>". $ffmpeg;
                 }