Autoplaying of video's is something that cannot be guaranteed these days. Because of changes in browser policies autoplay won't work a lot of the times. If the video is muted it will probably play. With sound it probably won't play and a viewer will have to click it to start.
When clicking trough a magazine it can be that the user interaction with the page has been noticed and the video will automatically play, even with sound. A browser like Chrome will also keep track of the media pages you view and if you play video a lot on some of the pages the chances are bigger that autoplay will work immediately. You can't assume your viewers have that kind of media behavior on your page already.
Mobile video's act the same way. Without sound, autoplay will probably work. With sound the video won't autoplay.
These rules also apply for background audio/music of pro pages. There's a big chance the audio will play when there has been interaction with the publication. Also be sure to test this.