Building FFmpeg from source for Android on Linux

This page explains how to configure and build FFmpeg for Android. Compilation for Android is a cross-compilation and presumes using Linux as a host system. The required steps are:

Get the FFmpeg source code.
Install the required dependencies.
Configure FFmpeg from the command line.
Build the development libraries.

Get the FFmpeg source code

You can get the FFmpeg source code in these ways:

Download from the FFmpeg download page .
Clone from git. For example, this command clones the version 7.1.1 of the FFmpeg sources to ~/ffmpeg .
```
git clone --branch n7.1.1 https://git.ffmpeg.org/ffmpeg.git ffmpeg
							
```

It is recommended to use the same FFmpeg version as documented in the Qt Multimedia main page .

The following paragraphs assumes that you store the FFmpeg source code under ~/ffmpeg .

先决条件

To build FFmpeg, these tools and packages are required:

Yasm.
Developer packages for your chosen security backend (see below).

You'll also need the Android NDK, SDK, and JDK installed and configured. You can find more information on setting these up here Qt for Android 快速入门 .

Installing packages

To install the required packages (including Yasm for FFmpeg), run:

apt-get install yasm

Additionally, if you're enabling a security backend, you need the corresponding developer package, for example:

apt-get install libssl-dev

For other backends, install the relevant packages:

For OpenSSL: libssl-dev .
For GnuTLS: libgnutls-dev .
For LibreSSL (libtls): libtls-dev .
For MbedTLS: libmbedtls-dev .

Set environment variables

This part is not strictly necessary but it'll help with keeping configure command a bit cleaner and shorter.

The following command assumes that Andorid SDK is installed to ~/Android/sdk and Android NDK version is 26.1.10909125.

export ANDROID_NDK_ROOT=~/Android/sdk/ndk/26.1.10909125

It is recommended to use the same NDK version as documented in the Qt for Android 快速入门 .

The architecture you should build for depends on the target devices:

aarch64 (ARM64-v8a): Used by most modern Android devices (64-bit).
armv7 (armeabi-v7a): For older 32-bit ARM devices.
x86: Mainly for Android emulators running on Intel processors.
x86_64: For 64-bit Intel-based emulators or specialized devices.

Setup architecture-specific variables

aarch64

export ARCH=aarch64
export TOOLCHAIN_ARCH=aarch64-linux-android
export CPU=armv8-a

armv7

export ARCH=armv7
export TOOLCHAIN_ARCH=armv7a-linux-androideabi
export CPU=armv7-a

x86

export ARCH=x86
export TOOLCHAIN_ARCH=i686-linux-android
export CPU=i686

x86_64

export ARCH=x86_64
export TOOLCHAIN_ARCH=x86_64-linux-android
export CPU=x86-64

Configuring and building FFmpeg

创建 build-android directory inside the ~/ffmpeg directory and navigate into it:

mkdir ~/ffmpeg/build-android
cd ~/ffmpeg/build-android

To configure FFmpeg, run:

../configure --prefix=../install-android --disable-doc --enable-network --enable-shared \
    --host-os=linux-x86_64 --target-os=android \
    --enable-cross-compile --arch=${ARCH} --cpu=${CPU} \
    --enable-jni --enable-mediacodec \
    --sysroot=${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/sysroot \
    --sysinclude=${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/include/ \
    --cc=${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/${TOOLCHAIN_ARCH}24-clang \
    --cxx=${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/${TOOLCHAIN_ARCH}24-clang++ \
    --strip=${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-strip

The --prefix argument specifies a path where the FFmpeg development libraries are installed after building. The documentation is not needed, but network features should be enabled. To build FFmpeg as static libraries, omit the --enable-shared 选项。

If you're building FFmpeg with a security backend, you have 4 options to choose from (the same as when building for Linux) but only OpenSSL is tested by QtMultimedia maintainers for now. Choose the appropriate option and add it during FFmpeg configuration:

--enable-openssl # For OpenSSL
--enable-gnutls # For GnuTLS
--enable-libtls # For LibreSSL (libtls)
--enable-mbedtls # For MbedTLS

If you're using OpenSSL you also need to add following options during FFmpeg configuration. Don't forget to replace <ANDROID_OPENSSL_INCLUDE_DIR> and <ANDROID_OPENSSL_LIBS_DIR> with actual paths.

--extra-cflags=-I<ANDROID_OPENSSL_INCLUDE_DIR> --extra-ldflags=-L<ANDROID_OPENSSL_LIBS_DIR>

If security backend is included, you should take care about its delivery yourself, ensuring correct libraries are installed on target platform or using stubs. The OpenSSL libraries that are linked must be called libssl.so and libcrypto.so , without any versioning suffixes. The user has to guarantee that libraries are of the same ABI version as OpenSSL headers FFmpeg was compiled with. For more information, see 为 Android 添加 OpenSSL 支持 .

Once the configure command finishes, build and install FFmpeg using the make 命令。

make -j install

If the build completes without errors, FFmpeg development libraries are installed in the ../install-android directory. If you build Qt Multimedia, this path is stored in the FFMPEG_DIR variable used when configuring Qt Multimedia.