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How To Crop and Trim Videos In Kotlin for Android
A Beginner-friendly tutorial to learn how to crop and trim videos in Android with FFmpeg.
Cropping and trimming videos is a notoriously difficult task to achieve on Android. One way to implement this functionality is by using FFmpeg a free open-source suite of tools that can perform a wide range of tasks, from video converting to editing. Normally FFmpeg is used from the command line, to use it correctly in Android you have to understand its underlying APIs and how to use them.
In this tutorial, you will learn how to crop and trim videos in Android by using FFmpeg. Even if you are a beginner you should be able to follow the steps to achieve the desired results.
I try to summarise the most important basics that you need to know to manipulate videos with FFmpeg. After reading this article you should be able to use it in your own applications. Furthermore, I have developed a sample application and library that can be used to trim and crop videos with an Android device.
What is FFmpeg
FFmpeg is a great multimedia framework that is able to mux, demux, decode, encode, transcode, filter, stream, and play most media content that exists. FFmpeg supports different tools that can be used to develop an application to manipulate any kind of media to the desired output. You do not have any limitations on what to do with multimedia when using FFmpeg.
Unfortunately, to use FFmpeg in an Android App using Kotlin you have to compile and build the libraries to use them as a dependency in your project. This process is not straightforward because you have to manually compile a C/C++ library with help of the Android NDK.
Luckily, many people already have done this and we are able to use their compiled library in our project. However, if you want to compile FFmpeg from scratch you can do this. All necessary information should be available within the android developer documentation.
To show you how we can use FFmpeg in our app I will use a compiled FFmpeg library that can be found here: https://github.com/WritingMinds/ffmpeg-android-java. To find other FFmpeg libraries you can have a look at the official FFmpeg wiki…
