diff --git a/lib/Alchemy/Phrasea/Filesystem/FilesystemService.php b/lib/Alchemy/Phrasea/Filesystem/FilesystemService.php
index 6f93b8d516..a3db77e635 100644
--- a/lib/Alchemy/Phrasea/Filesystem/FilesystemService.php
+++ b/lib/Alchemy/Phrasea/Filesystem/FilesystemService.php
@@ -69,7 +69,16 @@ class FilesystemService
 
     public function generateTemporarySubdefPathname(\record_adapter $record, \databox_subdef $subdef, $tmpDir)
     {
-        return $tmpDir . $this->generateSubdefFilename($record, $subdef);
+        $tmpDir = \p4string::addEndSlash($tmpDir);
+        $ffmpegDir = $tmpDir."ffmpeg/";
+
+        if(!is_dir($ffmpegDir)){
+            $this->filesystem->mkdir($ffmpegDir);
+        }
+
+        $filenameSufix = $this->generateSubdefFilename($record, $subdef);
+
+        return $ffmpegDir . hash('sha256', $filenameSufix) . $filenameSufix;
     }
 
     /**
diff --git a/lib/Alchemy/Phrasea/Media/SubdefGenerator.php b/lib/Alchemy/Phrasea/Media/SubdefGenerator.php
index 851349730a..037b3d8f51 100644
--- a/lib/Alchemy/Phrasea/Media/SubdefGenerator.php
+++ b/lib/Alchemy/Phrasea/Media/SubdefGenerator.php
@@ -174,10 +174,10 @@ class SubdefGenerator
                 return;
             }
 
-            $tmpDir = $this->app['conf']->get(['registry', 'executables', 'ffmpeg-tmp-directory']);
+            $tmpDir = $this->app['conf']->get(['main', 'storage', 'tmp_files']);
             $destFile = null;
 
-            if($subdef_class->getSpecs() instanceof Video && !empty($tmpDir) && is_dir($tmpDir)){
+            if($subdef_class->getSpecs() instanceof Video && !empty($tmpDir)){
                 $destFile = $pathdest;
                 $pathdest = $this->filesystem->generateTemporarySubdefPathname($record, $subdef_class, $tmpDir);
             }