@@ -498,7 +498,7 @@ static int decode_i_block(FourXContext *f, int16_t *block)

     if (get_bits_left(&f->gb) < 2){

         av_log(f->avctx, AV_LOG_ERROR, "%d bits left before decode_i_block()\n", get_bits_left(&f->gb));

-        return -1;

+        return AVERROR_INVALIDDATA;

     }

     /* DC coef */

@@ -732,7 +732,7 @@ static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length)

         for (x = 0; x < width; x += 16) {

             unsigned int color[4] = { 0 }, bits;

             if (buf_end - buf < 8)

-                return -1;

+                return AVERROR_INVALIDDATA;

             // warning following is purely guessed ...

             color[0] = bytestream2_get_le16u(&g3);

             color[1] = bytestream2_get_le16u(&g3);