ffmpeg-android-maker

Here is a script that downloads the source code of FFmpeg library and assembles it for Android. The script produces shared libraries (*.so files) as well as header files (*.h files). The output structure is represented in the image.

The script also produces ffmpeg and ffprobe executables that can be used in Android's terminal directly or can even be embedded into an Android app. They can be found in build directory after the successful build.

The main focus of ffmpeg-android-maker is to prepare shared libraries for seamless integration into an Android project. The script prepares the output directory that is meant to be used. And it's not the only thing this project does.

By default this script downloads and builds the FFmpeg 4.4, but the version can be overridden.

The details of how this script is implemented are described in this series of posts:

• Part 1
• Part 2
• Part 3

The WIKI contains a lot of useful information.

Customization

The actual content of output directory depends on how the FFmpeg was configured before assembling. The master branch of ffmpeg-android-maker builds 'vanilla' version of FFmpeg. This means all default components and shared libraries are built (according to the image).

The what-the-codec branch contains certain customizations in build scripts of FFmpeg and certain external libraries. These customizations are meant to be an example of how this project can be tuned to obtain the only functionality that is actually needed. What is actually customized can be seen here.

The WhatTheCodec Android app uses only a subset of FFmpeg's functionality, so the redundant parts are not even compiled. This gives much smaller output binaries.

Also there are a lot of arguments that you can pass to the ffmpeg-android-maker.sh script for tuning certain features. Check this WIKI page out for more info.

Supported Android ABIs

• armeabi-v7a (with NEON)
• arm64-v8a
• x86
• x86_64

If you need to build only some of these ABIs, you can do so by specifying a flag.

Supported host OS

Regardless of the OS you use, you need to setup it before executing the script. Please follow the instructions in Requirements section.

On macOS and Linux the script is supported natively. Just execute it script in the terminal.

On Windows 10 you can use WSL technology to install Ubuntu 20.04 LTS app. Then follow the Linux way of executing the script. Note that you will need to manually install exactly Linux versions of Android SDK and NDK into your Linux subsystem. The Dockerfile may help to understand how to do the setup.

Also on any OS you can use Docker tool to execute the script. Check this WIKI page out to understand benefits of this approach.

Requirements

The script assumes you have Android SDK and NDK already installed. In order to tell the script their locations you have to define 2 environment variables:

• ANDROID_SDK_HOME - absolute path to your Android SDK
• ANDROID_NDK_HOME - absolute path to your Android NDK

The script expects to use at least Android NDK r19 (both r20 and r21 also work ok).

Certain external libraries require additional software to be installed. Check this WIKI page out for more info. Note that if you don't need these external libraries then you also don't need to install the additional software. These external libraries are not built by default.

Features

Add an arbitrary external library that FFMpeg supports to the building process. Just specify how the source code needs to be downloaded and how to perform the build operation. More about this is here.

Setting your own FFmpeg version and origin. You can actually override the version of FFmpeg used by the script. See details here.

Test your script in a cloud. This repository has CI integration and you can use it too for your own configurations. See details here.

Text relocations monitoring. After an assembling is finished you can look into stats/text-relocations.txt file. This file lists all *.so files that were built and reports if any of them has text relocations. If you don't see any mentioning of 'TEXTREL' in the file, you are good. Otherwise, you will see exact binaries that have this problem. The Github Actions' Compilability check build will automatically fail if text relocations occur.

License

The ffmpeg-android-maker's source code is available under the MIT license. See the LICENSE.txt file for more details.

However, the binaries that are produced have different license. The FFmpeg itself is under LGPL 2.1. Enabling certain external libraries (like libx264) changes the license to be GPL 2 or later.