From 76aff8478883858f0e46746044348ebb16dc3c67 Mon Sep 17 00:00:00 2001
From: cudawarped <12133430+cudawarped@users.noreply.github.com>
Date: Thu, 10 Feb 2022 16:45:34 +0000
Subject: [PATCH] Merge pull request #21561 from
 cudawarped:ffmpeg_prefer_tcp_default

Default FFMPEG VideoCapture backend to rtsp_flags=prefer_tcp

* Make the VideoCapture ffmpeg backends default rtsp connection type prefer_tcp.

* Ensure that the ffmpeg version of avformat is checked.
---
 modules/videoio/src/cap_ffmpeg_impl.hpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/modules/videoio/src/cap_ffmpeg_impl.hpp b/modules/videoio/src/cap_ffmpeg_impl.hpp
index 2188c25444..47dc00ab04 100644
--- a/modules/videoio/src/cap_ffmpeg_impl.hpp
+++ b/modules/videoio/src/cap_ffmpeg_impl.hpp
@@ -980,7 +980,11 @@ bool CvCapture_FFMPEG::open(const char* _filename, const VideoCaptureParameters&
     char* options = getenv("OPENCV_FFMPEG_CAPTURE_OPTIONS");
     if(options == NULL)
     {
+#if LIBAVFORMAT_VERSION_MICRO >= 100  && LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(55, 48, 100)
+        av_dict_set(&dict, "rtsp_flags", "prefer_tcp", 0);
+#else
         av_dict_set(&dict, "rtsp_transport", "tcp", 0);
+#endif
     }
     else
     {