diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index 3f8061f942..bbddef4876 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -694,10 +694,13 @@ static int decode_i_frame(FourXContext *f, const uint8_t *buf, int length){
     unsigned int prestream_size;
     const uint8_t *prestream;
 
-    if (bitstream_size > (1<<26) || length < bitstream_size + 12)
-        return -1;
-    prestream_size = 4*AV_RL32(buf + bitstream_size + 4);
-    prestream = buf + bitstream_size + 12;
+    if (length < bitstream_size + 12) {
+        av_log(f->avctx, AV_LOG_ERROR, "packet size too small\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    prestream_size = 4 * AV_RL32(buf + bitstream_size + 4);
+    prestream      = buf + bitstream_size + 12;
 
     if (prestream_size > (1<<26) ||
         prestream_size != length - (bitstream_size + 12)){
diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
index 2f07af8c4b..3abc78b85a 100644
--- a/libavcodec/vp3.c
+++ b/libavcodec/vp3.c
@@ -1514,7 +1514,10 @@ static void render_slice(Vp3DecodeContext *s, int slice)
                     /* invert DCT and place (or add) in final output */
 
                     if (s->all_fragments[i].coding_method == MODE_INTRA) {
-                        vp3_dequant(s, s->all_fragments + i, plane, 0, block);
+                        int index;
+                        index = vp3_dequant(s, s->all_fragments + i, plane, 0, block);
+                        if (index > 63)
+                            continue;
                         if(s->avctx->idct_algo!=FF_IDCT_VP3)
                             block[0] += 128<<3;
                         s->dsp.idct_put(
@@ -1522,7 +1525,10 @@ static void render_slice(Vp3DecodeContext *s, int slice)
                             stride,
                             block);
                     } else {
-                        if (vp3_dequant(s, s->all_fragments + i, plane, 1, block)) {
+                        int index = vp3_dequant(s, s->all_fragments + i, plane, 1, block);
+                        if (index > 63)
+                            continue;
+                        if (index > 0) {
                         s->dsp.idct_add(
                             output_plane + first_pixel,
                             stride,
diff --git a/libavcodec/wma.c b/libavcodec/wma.c
index 67599b7eab..8f464619c2 100644
--- a/libavcodec/wma.c
+++ b/libavcodec/wma.c
@@ -137,6 +137,9 @@ int ff_wma_init(AVCodecContext *avctx, int flags2)
 
     /* compute MDCT block size */
     s->frame_len_bits = ff_wma_get_frame_len_bits(s->sample_rate, s->version, 0);
+    s->next_block_len_bits = s->frame_len_bits;
+    s->prev_block_len_bits = s->frame_len_bits;
+    s->block_len_bits      = s->frame_len_bits;
 
     s->frame_len = 1 << s->frame_len_bits;
     if (s->use_variable_block_len) {
diff --git a/libswscale/utils.c b/libswscale/utils.c
index 984f2c52fa..bdbc5bcadc 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -44,6 +44,7 @@
 #include "libavutil/cpu.h"
 #include "libavutil/avutil.h"
 #include "libavutil/bswap.h"
+#include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"