Ticking noise coming from motor?

I just recently developed a hard knock sound in the motor or possibly the timing chain. It only happens when I am on the gas when it is idling it runs and idles fine usually. It did have trouble starting up after shutting it off though a few times. Not really sure what it is I am sending a video of the noise that it's making hopefully you can hear it clearly in the video. I am just curious as to what it might be or what to look for.