
<     jzero_far((void *) output_buf[row], (size_t) (width * sizeof(JSAMPLE)));
---
>     if (output_buf[row] != NULL) {
>         jzero_far((void *) output_buf[row], (size_t) (width * sizeof(JSAMPLE)));
>     } else {
>         /* Handle null pointer error */
>     }
