Node fluent ffmpeg: How to add padding and background image?

Question

I am currently using the npm package fluent-ffmpeg:

https://github.com/fluent-ffmpeg/node-fluent-ffmpeg

I would like to get this result:

But I do not know how to do that.
To be more precise I would like to resize and center the video and then add background image.

This is my current code (but it's not good):

const command = ffmpeg(video_path)
.size('640x480')
.autopad(true, 'pink')
.on('error', function(err) {
    console.log('An error occurred: ' + err.message);
})
.on('end', function() {
    
    console.log('Processing finished !');

    const command2 = ffmpeg(destination_path1)
    .size('1920x1080')
    .applyAutoPadding(true, 'pink')
    .on('error', function(err) {
    console.log('An error occurred: ' + err.message);
    })
    .on('end', function() {
    console.log('Processing finished !');
    })
    .save(destination_path2);

})
.save(destination_path1);

Can you help me?

Thank you so much