avs: return meaningful error codes.

libavcodec/avs.c

@@ -54,14 +54,14 @@ avs_decode_frame(AVCodecContext * avctx,
     AVFrame *const p =  &avs->picture;
     const uint8_t *table, *vect;
     uint8_t *out;
-    int i, j, x, y, stride, vect_w = 3, vect_h = 3;
+    int i, j, x, y, stride, ret, vect_w = 3, vect_h = 3;
     AvsVideoSubType sub_type;
     AvsBlockType type;
     GetBitContext change_map;
 
-    if (avctx->reget_buffer(avctx, p)) {
+    if ((ret = avctx->reget_buffer(avctx, p)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
-        return -1;
+        return ret;
     }
     p->reference = 1;
     p->pict_type = AV_PICTURE_TYPE_P;
@@ -94,7 +94,7 @@ avs_decode_frame(AVCodecContext * avctx,
     }
 
     if (type != AVS_VIDEO)
-        return -1;
+        return AVERROR_INVALIDDATA;
 
     switch (sub_type) {
     case AVS_I_FRAME:
@@ -116,7 +116,7 @@ avs_decode_frame(AVCodecContext * avctx,
         break;
 
     default:
-      return -1;
+      return AVERROR_INVALIDDATA;
     }
 
     if (buf_end - buf < 256 * vect_w * vect_h)