$OpenBSD: patch-libaf_af_c,v 1.2 2005/09/04 23:51:52 espie Exp $
--- libaf/af.c.orig	Sat Aug 27 13:31:21 2005
+++ libaf/af.c	Sun Sep  4 00:17:07 2005
@@ -370,7 +370,8 @@ int af_init(af_stream_t* s, int force_ou
 
   // If force_output isn't set do not compensate for output format
   if(!force_output){
-    memcpy(&s->output, s->last->data, sizeof(af_data_t));
+    if (s->last)
+      memcpy(&s->output, s->last->data, sizeof(af_data_t));
     return 0;
   }
 
@@ -378,7 +379,7 @@ int af_init(af_stream_t* s, int force_ou
   if((AF_INIT_TYPE_MASK & s->cfg.force) != AF_INIT_FORCE){
     af_instance_t* af = NULL; // New filter
     // Check output frequency if not OK fix with resample
-    if(s->last->data->rate!=s->output.rate){
+    if(!s->last || s->last->data->rate!=s->output.rate){
       // try to find a filter that can change samplrate
       af = af_control_any_rev(s, AF_CONTROL_RESAMPLE_RATE | AF_CONTROL_SET,
                &(s->output.rate));
@@ -395,7 +396,7 @@ int af_init(af_stream_t* s, int force_ou
 	    af = af_prepend(s,s->first,resampler);
 	}		
 	else{
-	  if(!strcmp(s->last->info->name,"format"))
+	  if(s->last && !strcmp(s->last->info->name,"format"))
 	    af = af_prepend(s,s->last,resampler);
 	  else
 	    af = af_append(s,s->last,resampler);
@@ -423,8 +424,8 @@ int af_init(af_stream_t* s, int force_ou
       
     // Check number of output channels fix if not OK
     // If needed always inserted last -> easy to screw up other filters
-    if(s->last->data->nch!=s->output.nch){
-      if(!strcmp(s->last->info->name,"format"))
+    if(!s->last || s->last->data->nch!=s->output.nch){
+      if(s->last && !strcmp(s->last->info->name,"format"))
 	af = af_prepend(s,s->last,"channels");
       else
 	af = af_append(s,s->last,"channels");
@@ -436,8 +437,8 @@ int af_init(af_stream_t* s, int force_ou
     }
     
     // Check output format fix if not OK
-    if(s->last->data->format != s->output.format){
-      if(strcmp(s->last->info->name,"format"))
+    if(!s->last || s->last->data->format != s->output.format){
+      if(!s->last || strcmp(s->last->info->name,"format"))
 	af = af_append(s,s->last,"format");
       else
 	af = s->last;