Backport from trunk [24695]: set qmin=3 in ffmpeg encode when bitrate is set...

Backport from trunk [24695]: set qmin=3 in ffmpeg encode when bitrate is set and user hasn't defined qmin/qmax self

modules/codec/ffmpeg/encoder.c

@@ -528,7 +528,7 @@ int E_(OpenEncoder)( vlc_object_t *p_this )
             (p_sys->i_qmax == 0) && (p_sys->i_qmin == 0) )
         {
             p_sys->i_qmax = 51;
-            p_sys->i_qmin = 10;
+            p_sys->i_qmin = 3;
         }
 
         if( p_sys->i_qmin > 0 )