rv40: Return more meaningful error codes

Signed-off-by: Diego Biurrun <diego@biurrun.de>

libavcodec/rv40.c

@@ -130,22 +130,23 @@ static int rv40_parse_slice_header(RV34DecContext *r, GetBitContext *gb, SliceIn
     int mb_bits;
     int w = r->s.width, h = r->s.height;
     int mb_size;
+    int ret;
 
     memset(si, 0, sizeof(SliceInfo));
     if(get_bits1(gb))
-        return -1;
+        return AVERROR_INVALIDDATA;
     si->type = get_bits(gb, 2);
     if(si->type == 1) si->type = 0;
     si->quant = get_bits(gb, 5);
     if(get_bits(gb, 2))
-        return -1;
+        return AVERROR_INVALIDDATA;
     si->vlc_set = get_bits(gb, 2);
     skip_bits1(gb);
     si->pts = get_bits(gb, 13);
     if(!si->type || !get_bits1(gb))
         rv40_parse_picture_size(gb, &w, &h);
-    if(av_image_check_size(w, h, 0, r->s.avctx) < 0)
-        return -1;
+    if ((ret = av_image_check_size(w, h, 0, r->s.avctx)) < 0)
+        return ret;
     si->width  = w;
     si->height = h;
     mb_size = ((w + 15) >> 4) * ((h + 15) >> 4);