diff --git a/libavformat/au.c b/libavformat/au.c
index 50f22a8c9a..4a8353c444 100644
--- a/libavformat/au.c
+++ b/libavformat/au.c
@@ -140,16 +140,9 @@ static int au_read_header(AVFormatContext *s,
     }
 
     /* now we are ready: build format streams */
-    st = av_malloc(sizeof(AVStream));
+    st = av_new_stream(s, 0);
     if (!st)
         return -1;
-    avcodec_get_context_defaults(&st->codec);
-
-    s->nb_streams = 1;
-    s->streams[0] = st;
-
-    st->id = 0;
-    
     st->codec.codec_type = CODEC_TYPE_AUDIO;
     st->codec.codec_tag = id;
     st->codec.codec_id = codec;
diff --git a/libavformat/ffm.c b/libavformat/ffm.c
index de2ea6bef1..7eb3ca4e88 100644
--- a/libavformat/ffm.c
+++ b/libavformat/ffm.c
@@ -368,7 +368,7 @@ static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
     FFMStream *fst;
     ByteIOContext *pb = &s->pb;
     AVCodecContext *codec;
-    int i;
+    int i, nb_streams;
     uint32_t tag;
 
     /* header */
@@ -386,17 +386,15 @@ static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
         ffm->file_size = (uint64_t_C(1) << 63) - 1;
     }
 
-    s->nb_streams = get_be32(pb);
+    nb_streams = get_be32(pb);
     get_be32(pb); /* total bitrate */
     /* read each stream */
-    for(i=0;i<s->nb_streams;i++) {
+    for(i=0;i<nb_streams;i++) {
         char rc_eq_buf[128];
 
-        st = av_mallocz(sizeof(AVStream));
+        st = av_new_stream(s, 0);
         if (!st)
             goto fail;
-        avcodec_get_context_defaults(&st->codec);
-        s->streams[i] = st;
         fst = av_mallocz(sizeof(FFMStream));
         if (!fst)
             goto fail;
@@ -611,7 +609,7 @@ offset_t ffm_read_write_index(int fd)
     read(fd, buf, 8);
     pos = 0;
     for(i=0;i<8;i++)
-        pos |= buf[i] << (56 - i * 8);
+        pos |= (int64_t)buf[i] << (56 - i * 8);
     return pos;
 }
 
diff --git a/libavformat/swf.c b/libavformat/swf.c
index 60d931e2bf..2e2201f960 100644
--- a/libavformat/swf.c
+++ b/libavformat/swf.c
@@ -481,17 +481,14 @@ static int swf_read_header(AVFormatContext *s, AVFormatParameters *ap)
             get_le16(pb);
             /* if mp3 streaming found, OK */
             if ((v & 0x20) != 0) {
-                st = av_mallocz(sizeof(AVStream));
+                st = av_new_stream(s, 0);
                 if (!st)
                     return -ENOMEM;
-                avcodec_get_context_defaults(&st->codec);
 
                 if (v & 0x01)
                     st->codec.channels = 2;
                 else
                     st->codec.channels = 1;
-                s->nb_streams = 1;
-                s->streams[0] = st;
 
                 switch((v>> 2) & 0x03) {
                 case 1: