/* check signature */
if (buf_size < 8 ||
- memcmp(buf, ff_pngsig, 8) != 0 &&
- memcmp(buf, ff_mngsig, 8) != 0)
- return -1;
+ (memcmp(buf, ff_pngsig, 8) != 0 && memcmp(buf, ff_mngsig, 8) != 0)) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid PNG signature (%d).\n", buf_size);
+ return AVERROR_INVALIDDATA;
+ }
bytestream2_init(&s->gb, buf + 8, buf_size - 8);
s->y = s->state = 0;