I am converting a video generation library from NodeJS to GO that primarily uses FFMPEG for all the video processing. I already have all the FFMPEG commands written out to do the generation I want. The issue is that when I try to run the command through the os/exec package, it fails. However, if I copy the exact command and run it directly in the terminal it works and I cannot figure out why that is. My code that runs the command is below:
command := "ffmpeg -y -loop 1 -i image.png -vf 'fade=in:0:15,fade=out:105:15' -c:v mpeg2video -t 5 -s 1280x720 -r 30 -q:v 1 -preset ultrafast image.mpg"
parts := strings.Fields(command)
cmd := exec.Command(parts[0], parts[1:]...)
cmd.Stderr = os.Stderr
cmd.Stdout = os.Stdout
err := cmd.Run()
if err != nil {
panic(err)
}
The ffmpeg error I get when I try to run this code is:
[AVFilterGraph @ 0x22a9bc0] No such filter: 'fade=in:0:15,fade=out:105:15'
Error opening filters!
2016/08/17 17:48:53 exit status 1
Like I previously stated, if I copy the EXACT command:
ffmpeg -y -loop 1 -i image.png -vf 'fade=in:0:15,fade=out:105:15' -c:v mpeg2video -t 5 -s 1280x720 -r 30 -q:v 1 -preset ultrafast image.mpg
and run it directly in the terminal, it works no problem.
PLEASE HELP.
When you are using strings.Fields(command), the fields are being split on spaces. This results in the parts slice containing a value 'fade=in:0:15,fade=out:105:15', with quotes. This complete value (with quotes) is being passed to the ffmpeg command, which the command is unable to recognize.
A shell would strip off these quotes and pass the string fade=in:0:15,fade=out:105:15 only which Go isn't doing. To fix, try:
// remove the quotes around fade=in:0:15,fade=out:105:15
command := "ffmpeg -y -loop 1 -i image.png -vf fade=in:0:15,fade=out:105:15 -c:v mpeg2video -t 5 -s 1280x720 -r 30 -q:v 1 -preset ultrafast image.mpg"
parts := strings.Fields(command)