Compile FFmpeg for iOS ARM64

Compiling FFmpeg for the iOS arm64 architecture allows developers to integrate powerful audio and video processing capabilities into modern iOS applications. This guide provides a straightforward, step-by-step walkthrough to configure your macOS environment, set up the required build tools, and compile FFmpeg into static libraries (.a files) optimized for 64-bit iOS devices.

Prerequisites

Before starting, ensure you have Xcode and its Command Line Tools installed on your macOS system. You will also need gas-preprocessor, which is required to compile the assembly files in FFmpeg for iOS.

1. Install gas-preprocessor by running the following commands in your Terminal:

   sudo curl -L https://github.com/libav/gas-preprocessor/raw/master/gas-preprocessor.pl -o /usr/local/bin/gas-preprocessor.pl
   sudo chmod +x /usr/local/bin/gas-preprocessor.pl

2. Clone the official FFmpeg source code repository:

   git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
   cd ffmpeg

Set Up Environment Variables

To cross-compile for iOS, you must point the compiler to the official iOS SDK provided by Xcode. Run these commands to define the target SDK, compiler, and assembler paths:

# Get the path of the iOS device SDK
SDK_PATH=$(xcrun --sdk iphoneos --show-sdk-path)

# Locate the clang compiler within Xcode
CC=$(xcrun --sdk iphoneos --find clang)

# Set up the assembler using gas-preprocessor
AS="gas-preprocessor.pl -as-one-line -- $CC"

Configure the Build

Configure the FFmpeg build system for the arm64 architecture. This configuration disables shared libraries (since iOS requires static linking for custom FFmpeg builds) and disables unnecessary tools like the FFmpeg CLI program to keep the library size small.

Run the following configuration command inside the ffmpeg directory:

./configure \
    --target-os=darwin \
    --arch=arm64 \
    --cc="$CC" \
    --as="$AS" \
    --sysroot="$SDK_PATH" \
    --extra-cflags="-arch arm64 -miphoneos-version-min=12.0" \
    --extra-ldflags="-arch arm64 -miphoneos-version-min=12.0" \
    --enable-cross-compile \
    --disable-shared \
    --enable-static \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe

Compile the Libraries

Once the configuration process completes successfully, compile the source code using all available CPU cores to speed up the process, and then install the output files.

# Clean any previous build artifacts
make clean

# Compile using multiple CPU cores
make -j$(sysctl -n hw.ncpu)

# Install the headers and static libraries into a local folder
make install DESTDIR=$(pwd)/build_arm64

Locate Your Compiled Files

Upon successful completion of the build, you will find the compiled static libraries (.a files) and their headers in the build_arm64 directory:

• Header Files: build_arm64/usr/local/include/
• Static Libraries: build_arm64/usr/local/lib/ (including libavcodec.a, libavformat.a, libavutil.a, etc.)

You can now drag these .a library files and header folders directly into your Xcode project to begin utilizing FFmpeg in your iOS application.