fix(previews): ffprobe hangs

Signed-off-by: Andrey Dyakov <adduxa@gmail.com>

Author: adduxa

AUTHORS

@@ -32,6 +32,7 @@
  - Andreas Pflug <dev@admin4.org>
  - Andrew Brown <andrew@casabrown.com>
  - Andrey Borysenko <andrey.borysenko@nextcloud.com>
+ - Andrey Dyakov <adduxa@gmail.com>
  - André Gaul <gaul@web-yard.de>
  - Andy Xheli <axheli@axtsolutions.com>
  - Anna Larch <anna@nextcloud.com>

lib/private/Preview/Movie.php

@@ -289,8 +289,8 @@ private function useHdr(string $absPath): bool {
 		if ($test_hdr_proc === false) {
 			return false;
 		}
-		$test_hdr_stdout = trim(stream_get_contents($test_hdr_pipes[1]));
 		$test_hdr_stderr = trim(stream_get_contents($test_hdr_pipes[2]));
+		$test_hdr_stdout = trim(stream_get_contents($test_hdr_pipes[1]));
 		proc_close($test_hdr_proc);
 		// search build options for libzimg (provides zscale filter)
 		$ffmpeg_libzimg_installed = strpos($test_hdr_stderr, '--enable-libzimg');