[FFmpeg-user] How to set preview of video?

[Michael Koch]

Am 30.04.2020 um 06:33 schrieb Gyan Doshi:
>
> Basic syntax is
>
> |ffmpeg -i file.mp4 -ss 15 -i file.mp4 -map 1:v:0 -map 0 \ -filter:v:0 
> scale=320:-1,trim=end_frame=1 -c copy -c:v:0 mjpeg -disposition:0 
> attached_pic out.mp4|

What's the meaning of the "|" characters at the beginning and end?
What's the meaning of the "\" character and how must this command line 
be modified for a Windows batch file?

Thanks,
Michael