[FFmpeg-user] ffmpeg watermark by -vcodec libx264

[saman exploit]

 hi i wanna know how to add watermark by -vcodec order , please help me

i dont want to use -filter_complex
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
''
shell_exec("$ffmpeg_b -y -i $video_file_full_path -vcodec libx264 -preset
{fast} -filter:v scale=3840:-2 -crf 26 $video_output_full_path_4096 2>&1");
''

please show me the good way , thank you