ffmpeg background process video conversion

Aah, great, thank you Christian. I understand now. Thank you also for your patience; I'm learning principles which will help for other things in future, and I'm sure other people can also benefit from the forum posts.

So after fixing the results inspection and running the command again, I get the following error
127
[LOG] /bin/bash: line 5: ffmpeg: command not found

I confirm that I do have ffmpeg installed and working properly, and if I take the same ffmpeg code from the script and paste that into terminal and execute it there, it runs correctly and generates the MP4 (obviously replacing the path variable with an actual path).

// Source file
// Path may have spaces
let sourceFile = sf.ui.finder.firstSelectedPath;

// Destination file
// Keep same name and path, change extension to MP4
let destinationFile = sourceFile.split('.').slice(0, -1).join('.') + '.mp4';

log(`MP4 conversion started`);

// ffmpeg video conversion to run in background (no terminal?)
var execResult = sf.system.exec({
        commandLine: `ffmpeg -r 25 -y -i "${sourceFile}" -nostdin -preset fast \
        -c:v libx264 -profile:v high -bf 2 -crf 17 -pix_fmt yuv420p -vf scale=1920:1080 \
        -color_primaries 1 -color_trc 1 -colorspace 1 \
        -c:a aac -b:a 384k -ar 48000 \
        -r 25 "${destinationFile}"`
    });

log(execResult.standardError);

log(execResult.result);

log(execResult.exitCode);

log(sourceFile);

log(destinationFile);