I'm building a web application that creates a slideshow mp4 video. It will be uploaded to S3 and viewed through HTML5 . The goal is to share it on instagram but instagram doesn't allow direct sharing through web. Hence, the alternative is to get the user to download it to their mobile device and upload it manually through the app.
On Android, I'm able to download the video using it's video controls or through <a href='s3-video-link.mp4' download>
However this doesn't work on IOS. How can I download a html5 video onto the mobile device? Can I download directly from s3 somehow? Or is there any possible option to get it to upload to instagram?