This is my command (url1, url2, url3, url4 are placeholders):
ffmpeg -i url1 -i url2 -i url3 -i url4 -filter_complex "[1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:v:0] concat=n=4:v=1:a=1 [v] [a]" -map [v] -map [a] /Users/myname/Downloads/f1-2017-07-12.mp4 -y
I get this error
Stream specifier ':v:0' in filtergraph description [1:v:0] [1:a:0] [2:v:0] [2:a:0] [3:v:0] [3:v:0] concat=n=4:v=1:a=1 [v] [a] matches no streams.
Not sure what is going on. I tried all urls individually and they all work (video and audio). I'm just getting this error when I try to concatenate them.
I also tried this using another syntax for filter_complex:
ffmpeg -i url1 -i url2 -i url3 -i url4 -filter_complex [0:0] [0:1] [1:0] [1:1] [2:0] [2:1] [3:0] [3:1] concat=n=4:v=1:a=1 [v] [a] -map [v] [a] /Users/timurridjanovic/Downloads/f1-2017-07-12.mp4 -y
And I get this error:
[AVFilterGraph @ 0x7ffe91703a00] No such filter: ''
Error initializing complex filters.
Invalid argument
Can someone help me?