diff --git a/libavcodec/vp5.c b/libavcodec/vp5.c
index 3ae7c25f51..46c7fd85f2 100644
--- a/libavcodec/vp5.c
+++ b/libavcodec/vp5.c
@@ -48,18 +48,18 @@ static int vp5_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
     {
         vp56_rac_gets(c, 8);
         if(vp56_rac_gets(c, 5) > 5)
-            return 0;
+            return AVERROR_INVALIDDATA;
         vp56_rac_gets(c, 2);
         if (vp56_rac_get(c)) {
             av_log(s->avctx, AV_LOG_ERROR, "interlacing not supported\n");
-            return 0;
+            return AVERROR_PATCHWELCOME;
         }
         rows = vp56_rac_gets(c, 8);  /* number of stored macroblock rows */
         cols = vp56_rac_gets(c, 8);  /* number of stored macroblock cols */
         if (!rows || !cols) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid size %dx%d\n",
                    cols << 4, rows << 4);
-            return 0;
+            return AVERROR_INVALIDDATA;
         }
         vp56_rac_gets(c, 8);  /* number of displayed macroblock rows */
         vp56_rac_gets(c, 8);  /* number of displayed macroblock cols */
@@ -68,11 +68,11 @@ static int vp5_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
             16*cols != s->avctx->coded_width ||
             16*rows != s->avctx->coded_height) {
             avcodec_set_dimensions(s->avctx, 16*cols, 16*rows);
-            return 2;
+            return VP56_SIZE_CHANGE;
         }
     } else if (!s->macroblocks)
-        return 0;
-    return 1;
+        return AVERROR_INVALIDDATA;
+    return 0;
 }
 
 static void vp5_parse_vector_adjustment(VP56Context *s, VP56mv *vect)
diff --git a/libavcodec/vp56.c b/libavcodec/vp56.c
index adde128a62..ca1c8f1115 100644
--- a/libavcodec/vp56.c
+++ b/libavcodec/vp56.c
@@ -524,10 +524,10 @@ int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
     }
 
     res = s->parse_header(s, buf, remaining_buf_size);
-    if (!res)
-        return -1;
+    if (res < 0)
+        return res;
 
-    if (res == 2) {
+    if (res == VP56_SIZE_CHANGE) {
         for (i = 0; i < 4; i++) {
             if (s->frames[i].data[0])
                 avctx->release_buffer(avctx, &s->frames[i]);
@@ -540,7 +540,7 @@ int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         return -1;
     }
 
-    if (res == 2) {
+    if (res == VP56_SIZE_CHANGE) {
         if (vp56_size_changed(s)) {
             avctx->release_buffer(avctx, p);
             return -1;
@@ -556,8 +556,8 @@ int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         remaining_buf_size -= alpha_offset;
 
         res = s->alpha_context->parse_header(s->alpha_context, buf, remaining_buf_size);
-        if (res != 1) {
-            if(res==2) {
+        if (res != 0) {
+            if(res==VP56_SIZE_CHANGE) {
                 av_log(avctx, AV_LOG_ERROR, "Alpha reconfiguration\n");
                 avctx->width  = bak_w;
                 avctx->height = bak_h;
diff --git a/libavcodec/vp56.h b/libavcodec/vp56.h
index 838ce48c3d..3f6f0e2646 100644
--- a/libavcodec/vp56.h
+++ b/libavcodec/vp56.h
@@ -40,6 +40,8 @@ typedef struct VP56mv {
     int16_t y;
 } VP56mv;
 
+#define VP56_SIZE_CHANGE 1
+
 typedef void (*VP56ParseVectorAdjustment)(VP56Context *s,
                                           VP56mv *vect);
 typedef void (*VP56Filter)(VP56Context *s, uint8_t *dst, uint8_t *src,
diff --git a/libavcodec/vp6.c b/libavcodec/vp6.c
index bf168c886e..c6ca13c5c0 100644
--- a/libavcodec/vp6.c
+++ b/libavcodec/vp6.c
@@ -51,7 +51,7 @@ static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
     int vrt_shift = 0;
     int sub_version;
     int rows, cols;
-    int res = 1;
+    int res = 0;
     int separated_coeff = buf[0] & 1;
 
     s->framep[VP56_FRAME_CURRENT]->key_frame = !(buf[0] & 0x80);
@@ -60,7 +60,7 @@ static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
     if (s->framep[VP56_FRAME_CURRENT]->key_frame) {
         sub_version = buf[1] >> 3;
         if (sub_version > 8)
-            return 0;
+            return AVERROR_INVALIDDATA;
         s->filter_header = buf[1] & 0x06;
         if (buf[1] & 1) {
             av_log_missing_feature(s->avctx, "Interlacing", 0);
@@ -78,7 +78,7 @@ static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
         /* buf[5] is number of displayed macroblock cols */
         if (!rows || !cols) {
             av_log(s->avctx, AV_LOG_ERROR, "Invalid size %dx%d\n", cols << 4, rows << 4);
-            return 0;
+            return AVERROR_INVALIDDATA;
         }
 
         if (!s->macroblocks || /* first frame */
@@ -89,7 +89,7 @@ static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
                 s->avctx->width  -= s->avctx->extradata[0] >> 4;
                 s->avctx->height -= s->avctx->extradata[0] & 0x0F;
             }
-            res = 2;
+            res = VP56_SIZE_CHANGE;
         }
 
         ff_vp56_init_range_decoder(c, buf+6, buf_size-6);
@@ -102,7 +102,7 @@ static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
         s->golden_frame = 0;
     } else {
         if (!s->sub_version || !s->avctx->coded_width || !s->avctx->coded_height)
-            return 0;
+            return AVERROR_INVALIDDATA;
 
         if (separated_coeff || !s->filter_header) {
             coeff_offset = AV_RB16(buf+1) - 2;
@@ -146,7 +146,7 @@ static int vp6_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
         if (buf_size < 0) {
             if (s->framep[VP56_FRAME_CURRENT]->key_frame)
                 avcodec_set_dimensions(s->avctx, 0, 0);
-            return 0;
+            return AVERROR_INVALIDDATA;
         }
         if (s->use_huffman) {
             s->parse_coeff = vp6_parse_coeff_huffman;