Only call av_register_all() if libavformat is older than version 58.9.100

This patch adds a preprocessor #define to ensure we only call the deprecated
function av_register_all() when working with versions of libavformat older
than 58.9.100.

The function av_register_all() was removed in ffmpeg 5.0.

Author: hughmcmaster

CMakeLists.txt

@@ -26,6 +26,9 @@ ENDIF (APPLE)
 
 PKG_CHECK_MODULES(LAVC libavcodec REQUIRED)
 PKG_CHECK_MODULES(LAVF libavformat REQUIRED)
+IF (${LAVF_VERSION} VERSION_LESS 58.9.100)
+  add_compile_definitions(LAVF_REGISTER_ALL=1)
+ENDIF ()
 PKG_CHECK_MODULES(LAVR libswresample REQUIRED)
 PKG_CHECK_MODULES(LAVU libavutil REQUIRED)
 PKG_CHECK_MODULES(LTAG taglib REQUIRED)

src/scan.c

@@ -64,13 +64,15 @@ static int             scan_nb_files   = 0;
 #define LUFS_TO_RG(L) (-18 - L)
 
 int scan_init(unsigned nb_files) {
+#ifdef LAVF_REGISTER_ALL
   /*
 	 * av_register_all() got deprecated in lavf 58.9.100
 	 * It is now useless
 	 * https://github.com/FFmpeg/FFmpeg/blob/70d25268c21cbee5f08304da95be1f647c630c15/doc/APIchanges#L86
 	 */
   if (avformat_version() < AV_VERSION_INT(58,9,100))
     av_register_all();
+#endif /* LAVF_REGISTER_ALL */
 
 	av_log_set_callback(scan_av_log);