diff --git a/libavformat/tls_openssl.c b/libavformat/tls_openssl.c
index 86e8935fee..2a3905891d 100644
--- a/libavformat/tls_openssl.c
+++ b/libavformat/tls_openssl.c
@@ -415,7 +415,11 @@ error:
  */
 static EVP_PKEY *pkey_from_pem_string(const char *pem_str, int is_priv)
 {
+#if OPENSSL_VERSION_NUMBER < 0x10002000L /* OpenSSL 1.0.2 */
+    BIO *mem = BIO_new_mem_buf((void *)pem_str, -1);
+#else
     BIO *mem = BIO_new_mem_buf(pem_str, -1);
+#endif
     if (!mem) {
         av_log(NULL, AV_LOG_ERROR, "BIO_new_mem_buf failed\n");
         return NULL;
@@ -445,7 +449,11 @@ static EVP_PKEY *pkey_from_pem_string(const char *pem_str, int is_priv)
  */
 static X509 *cert_from_pem_string(const char *pem_str)
 {
+#if OPENSSL_VERSION_NUMBER < 0x10002000L /* OpenSSL 1.0.2 */
+    BIO *mem = BIO_new_mem_buf((void *)pem_str, -1);
+#else
     BIO *mem = BIO_new_mem_buf(pem_str, -1);
+#endif
     if (!mem) {
         av_log(NULL, AV_LOG_ERROR, "BIO_new_mem_buf failed\n");
         return NULL;