When our new app Brain Train was finally cleared by QA for submission to the App Store, I stumbled upon an error when uploading the App Preview: “Your app video preview is in the wrong format”; we had made our video following the Creating App Previews document provided by Apple in their documentation, so I knew the encoding was correct and the error must be another one, after a quick search I found that the problem was that the resolution of the video was incorrect and you require a specific resolution for each device :
Armed with this new information I went to iMovie and tried to export our App Preview to every resolution required, but I quickly found out that you can’t change the export resolution in iMovie. After some more Google searches I came across some proposed solutions that went from using third party App to convert the output file to each of the format all the way to recording the App Preview in each device. It turned out that it was way more simple than that and probably the solution was somewhere in the manual for iMovie, but since we are always short of time nobody read the manual. I’m sure many other developer will come across this problem especially if you are making your own videos so we decided to share our solution and save sometime to whoever comes across this problem.
First of all I believe you should try to record your preview in at least three devices iPad, iPhone 6 and iPhone 6 Plus (or iPhone 5 since the share aspect ratio) if you have access to the device, but if you don’t have all the devices this works just fine:
- Create your video following the official Apple document Creating App Previews, but don’t export yet.
- Create poster frame for each required resolution: This can be a nice graphic with you app logo and company logo, or whatever you want your user to see in the App Store before opening the video. Just remember you need one for each resolution.
- Duplicate your movie 2 times inside iMovie (or 3 if you are doing a separate video for iPhone 5).
- Import your poster frames in iMovie and insert them as the first frame: You will insert one poster frame in each resolution, you can make this poster frame 2 or 3 seconds long and add some transitions it just has to be the first frame.
- Export each movie: Now when you go to share and export App Preview you will see that each video now has the correct resolution, what iMovie does is takes the first frame and set the export resolution to that frame dimensions.
Depending on your source video, iMovie might add black bars to compensate for the difference in resolutions, we settled for recording two movies one in iPad and one iPhone 5 (which we used for iPhone 5, 6 and 6 plus) to avoid black bars.
So there you go, if you have trouble exporting your App Preview movies this is a great solution.
If you have any question or suggestion add them in the comments or send us a tweet @pialoki
Have a great day,