You can download videos directly from Dropbox to Photo Library on iPhone or iPad, so you can play the videos offline anytime you like.
New Dropbox for iOS app has changed the way we can export videos from Dropbox. You can refer to this updated guide to
download videos from Dropbox to Camera Roll on iPhone or iPad.
The Dropbox app for iOS lets you download any videos from your Dropbox directly to your video album on iOS device. You firstly upload videos from other devices or computers to Dropbox. Then run Dropbox on iPhone and find the uploaded video on iPhone through Dropbox. However you will find immediately that the share button is grayed out. Here comes the trick to download videos from Dropbox to Photo Library. You must favorite the video selected in the Dropbox for iPhone or iPad, then you will notice that the share button is ready for use. See below figure.
Now tap on the share button in Dropbox, you will see options as Save to Photo Library and Open in ….. You can now download the video from Dropbox to iPhone by tapping on the Save to Photo Library. It is the simple act of favoriting in Dropbox for iPhone begins a download process you barely notice.
Now we know the trick that the Dropbox app will automatically download videos when you mark them as Favorites by viewing a video and tapping the star icon at the bottom of the screen.
Keep in mind that if the video downloaded from Dropbox to your iOS device is not natively support on iPhone or iPad, you need a third party video app or player to open or play the vide on iPhone. Alternatively you can also convert the video to iPhone compatible format on computer before uploading to Dropbox.