postprocess.c: filter name needs to be double 0 terminated

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
(cherry picked from commit f4f3300c09)
(cherry picked from commit 20ca827019)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>

libpostproc/postprocess.c

@@ -767,7 +767,8 @@ pp_mode *pp_get_mode_by_name_and_quality(const char *name, int quality)
     ppMode->maxClippedThreshold= 0.01;
     ppMode->error=0;
 
-    av_strlcpy(temp, name, GET_MODE_BUFFER_SIZE);
+    memset(temp, 0, GET_MODE_BUFFER_SIZE);
+    av_strlcpy(temp, name, GET_MODE_BUFFER_SIZE - 1);
 
     av_log(NULL, AV_LOG_DEBUG, "pp: %s\n", name);
 
@@ -823,7 +824,7 @@ pp_mode *pp_get_mode_by_name_and_quality(const char *name, int quality)
 
                 plen= strlen(p);
                 spaceLeft= p - temp + plen;
-                if(spaceLeft + newlen  >= GET_MODE_BUFFER_SIZE){
+                if(spaceLeft + newlen  >= GET_MODE_BUFFER_SIZE - 1){
                     ppMode->error++;
                     break;
                 }