Unknown decoder 'libx264'

Question

I have ffmpeg with libx264 enabled from BtbN for Windows 10. This is the command:

ffmpeg -f gdigrab -c:v libx264 -framerate 30 -i title="FiveM" -f flv rtmp://MYSITE.COM/stream/MYSECRETKEY

Unfortunately I get this output:

Unknown decoder 'libx264'

score 12 · Accepted Answer · answered Oct 29 '20 at 19:37

12

Position of options is important:

ffmpeg [input options] -i input [output options] output

You are trying to apply -c:v libx264 to the input, but you should apply it to the output:

ffmpeg -f gdigrab -framerate 30 -i title="FiveM" -c:v libx264 -f flv rtmp://MYSITE.COM/stream/MYSECRETKEY

With some suggested options added:

ffmpeg -f gdigrab -framerate 30 -i title="FiveM" -c:v libx264 -vf format=yuv420p -g 60 -b:v 3000k -maxrate 3000k -bufsize 6000k -f flv rtmp://MYSITE.COM/stream/MYSECRETKEY

Some services require audio, so you can add silent audio if needed:

ffmpeg -f gdigrab -framerate 30 -i title="FiveM" -re -f lavfi -i anullsrc -c:v libx264 -c:a aac -vf format=yuv420p -g 60 -b:v 3000k -maxrate 3000k -bufsize 6000k -f flv rtmp://MYSITE.COM/stream/MYSECRETKEY

answered Oct 29 '20 at 19:37

llogan

121,796
28
232
243

Thank you very much sir :-) – Reboot_My_Computer Oct 29 '20 at 20:23
thanks for this real helpful ... why is -vf format=yuv420p applied to the output? sorry im such a noob – danday74 Sep 03 '21 at 09:16
@danday74 For chroma subsampling that all players can handle. Otherwise libx264 will try to preserve color info but most players can't play advanced pixel formats. – llogan Sep 03 '21 at 16:08

Unknown decoder 'libx264'

1 Answers1