Golang : ffmpeg with os/exec.Command() returns non-zero status

Problem:

You want to use ffmpeg with os/exec.Command() and Run() to create your video files.

However, it keeps bombing out with the error message:

exit status 1

You are able to execute the command with the supplied parameters and flags just fine on your terminal.

What's going on? How to fix this?

Solution:

Golang's os/exec.Command() function does not have the shell=true feature like Python did. ffmpeg is very sensitive to white spaces when running from another program. To fix the problem, simply remove whitespaces by using , instead of + to assemble the flags and parameters to ffmpeg.

For example,

 cmd := exec.Command("ffmpeg", "-r "+recordedFPSstring+" -i "+videoFileName+" -r 6 temp_"+videoFileName)

to

 cmd := exec.Command("ffmpeg", "-r", recordedFPSstring, "-i", videoFileName, "-r", "6", "temp_"+videoFileName)