diff --git a/demux/demux.c b/demux/demux.c
index b9236832ce..acdee69d4b 100644
--- a/demux/demux.c
+++ b/demux/demux.c
@@ -167,21 +167,11 @@ struct demux_packet *new_demux_packet_from(void *data, size_t len)
     return dp;
 }
 
-void resize_demux_packet(struct demux_packet *dp, size_t len)
+void demux_packet_shorten(struct demux_packet *dp, size_t len)
 {
-    if (len > 1000000000) {
-        fprintf(stderr, "Attempt to realloc demux packet over 1 GB!\n");
-        abort();
-    }
-    assert(dp->allocation);
-    dp->buffer = realloc(dp->buffer, len + FF_INPUT_BUFFER_PADDING_SIZE);
-    if (!dp->buffer) {
-        fprintf(stderr, "Memory allocation failure!\n");
-        abort();
-    }
-    memset(dp->buffer + len, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+    assert(len <= dp->len);
     dp->len = len;
-    dp->allocation = dp->buffer;
+    memset(dp->buffer + dp->len, 0, FF_INPUT_BUFFER_PADDING_SIZE);
 }
 
 void free_demux_packet(struct demux_packet *dp)
diff --git a/demux/demux.h b/demux/demux.h
index d477bb45a9..222d3b8624 100644
--- a/demux/demux.h
+++ b/demux/demux.h
@@ -223,7 +223,7 @@ struct demux_packet *new_demux_packet(size_t len);
 // data must already have suitable padding
 struct demux_packet *new_demux_packet_fromdata(void *data, size_t len);
 struct demux_packet *new_demux_packet_from(void *data, size_t len);
-void resize_demux_packet(struct demux_packet *dp, size_t len);
+void demux_packet_shorten(struct demux_packet *dp, size_t len);
 void free_demux_packet(struct demux_packet *dp);
 struct demux_packet *demux_copy_packet(struct demux_packet *dp);
 
diff --git a/demux/demux_raw.c b/demux/demux_raw.c
index ad0c174c11..888b7ecfa0 100644
--- a/demux/demux_raw.c
+++ b/demux/demux_raw.c
@@ -231,7 +231,7 @@ static int raw_fill_buffer(demuxer_t *demuxer)
     dp->pts = (dp->pos  / p->frame_size) / p->frame_rate;
 
     int len = stream_read(demuxer->stream, dp->buffer, dp->len);
-    resize_demux_packet(dp, len);
+    demux_packet_shorten(dp, len);
     demuxer_add_packet(demuxer, demuxer->streams[0], dp);
 
     return 1;