The latest articles on DEV Community by Metail (@metail). https://dev.to/metail https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Forganization%2Fprofile_image%2F1812%2Fc9f13e6f-3da1-4359-98d3-ab236620f5aa.png https://dev.to/metail en David Gavilan Tue, 25 Feb 2020 14:54:59 +0000 https://dev.to/metail/scaling-videos-with-ffmpeg-for-app-previews-4c6b https://dev.to/metail/scaling-videos-with-ffmpeg-for-app-previews-4c6b <h2> The problem </h2> <p>When you upload video previews for your iOS app, they have to be in a specific resolution, usually matching the native resolution of the device. Check: <a href="https://help.apple.com/app-store-connect/?lang=en/#/dev4e413fcb8">App Preview Resolutions</a></p> <p>However, your video editor may not support those resolutions natively. When the iPhoneX was released, iMovie didn't support it and iPhoneX captures were exported as <code>750x1334</code> videos, instead of the native <code>886:1920</code> of the capture. Supposedly, iMovie has support for App Previews, but the support for latest devices sometimes lag behind.</p> <h2> Workaround with ffmpeg </h2> <p>You can use ffmpeg to crop and resize videos. I usually do it in 2 steps, because these command line tools can get really convoluted if you try to do it all in one go. Here's what you have to do for the iPhoneX example above:<br> </p> <div class="highlight"><pre class="highlight plaintext"><code>ffmpeg -i iPhoneX-iMovie.mp4 -filter:v "crop=616:1334:68:0" -c:a copy cropped.mp4 ffmpeg -i cropped.mp4 -vf scale=886:1920 -c:a copy iPhoneX-final.mp4 </code></pre></div> <p>Done. Now your iPhoneX video is ready for the App Store.</p> ios