diff --git a/inference_realesrgan_video.py b/inference_realesrgan_video.py
index 39fed08a5..3b383696c 100644
--- a/inference_realesrgan_video.py
+++ b/inference_realesrgan_video.py
@@ -348,6 +348,11 @@ def main():
     else:
         is_video = False
 
+    if is_video and args.input.endswith('.flv'):
+        mp4_path = args.input.replace('.flv', '.mp4')
+        os.system(f'ffmpeg -i {args.input} -codec copy {mp4_path}')
+        args.input = mp4_path
+
     if args.extract_frame_first and not is_video:
         args.extract_frame_first = False