Building FFmpeg for use in Swift - ios

With the new XCode/Swift release comes the ability to use binary dependencies. This seems to me to be an ideal time to create an SPM package for FFMpeg.
However, while I've spent the last year learning to code i Swift, I'm actually not all that familiar with how to build libraries, especially those as complex as FFmpeg with all the configurable libraries and third-party dependencies.
There's kewlbear's iOS build scripts, but these are for iOS/tvOS and ideally an FFMpeg SPM package would be usable for MacOS also. It's also not updated for the newest Xcode and Swift versions.
My personal interest is simply in audio and I don't need a lot of bells and whistles, but I figure the ideal situation would be a full package with the entire source and whatever dependencies it needs, and then when it's used as a package dependency, the compiler will just use the parts it needs.
I guess my question is...how would I ideally compile the ffmpeg code for this purpose. I'm trying to follow the directions for compiling yourself, but I'm stuck at the point of compiling gettext because I'm not sure if I should follow the directions (in the gettext source code) for compiling a fat binary for multiple architectures, and when I try to run:
./configure CC="gcc -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
CXX="g++ -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
CPP="gcc -E" CXXCPP="g++ -E"
I get the following error:
checking whether the C compiler works... no configure: error: in
`/Users/nolainecrusher/Downloads/FFMpeg-source/gettext-0.21/gettext-runtime':
configure: error: C compiler cannot create executables See
`config.log' for more details configure: error: ./configure failed for
gettext-runtime
and config.log doesn't really tell me anything useful:
This is what I see at the end of the log:
mkdir_p='$(MKDIR_P)' oldincludedir='/usr/include' pdfdir='${docdir}'
prefix='/usr/local' program_transform_name='s,x,x,' psdir='${docdir}'
sbindir='${exec_prefix}/sbin' sharedstatedir='${prefix}/com' subdirs='
gettext-runtime libtextstyle gettext-tools' sysconfdir='${prefix}/etc'
target_alias=''
I feel like maybe I'm going about this the wrong way, but I'm not sure what the right way is.

See the following:
A Swift wrapper package for FFmpeg and
A C wrapper package for FFmpeg
SwiftFFmpeg assumes ffmpeg is installed locally and will link with those libraries. Also, SwiftFFmpeg uses CFFmpeg as a package dependency, and your app can use SwiftFFmpeg as a dependency.
If you want to see a build script for compiling ffmpeg (x86_64 and arm64), check out my own audio player project.

Related

How to compile C into a universal library that works with iOS architectures

I'm trying to compile a very small amount of C source into a library that I can use in XCode for an iOS application.
The files are a single .c file and three header files. I'm very new to C, and no matter what I try I can't seem to get them to compile into a library that supports iOS architectures.
The files depend on the openssl library, and I've got that installed and working fine.
I just need to know the process of compiling these four files into a single library. I've found a plethora of information on the subject online, but I can't decipher which parts are necessary for what I'm trying to do.
I've tried the following:
gcc -fPIC -c main.c
gcc -shared -o mylib.so main.o -lcrypto -lssl
which seems to compile it for x86_64, (I've not tested the resulting file, just checked it's arch).
I've also tried
./configure --disable-shared --enable-utf8 --host=arm-apple-darwin CFLAGS="-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.1.sdk" CXXFLAGS="-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.1.sdk" LDFLAGS="-L." CC="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc" CXX="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++"
which only gives me errors
checking for arm-apple-darwin-gcc... no
checking for gcc... gcc
checking whether the C compiler works... no
configure: error: in `/Users/nathanf/compilec':
configure: error: C compiler cannot create executables
I've been scouring the internet for the last few days trying to figure this out, but it's so convoluted to cross compile just a few files and I'm frustrated so I came here for some input.
Any help would be greatly appreciated.

Problems Building MPFR using iOS SDK 8.3

I am having trouble building MPFR for iOS, armv7s architecture. I am using this command after successfully building GMP,
./configure CC=clang CPP="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -E" CPPFLAGS="-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.3.sdk/ -miphoneos-version-min=8.0 -arch armv7s -target arm-apple-darwin" --host=aarch64-apple-darwin --disable-assembly --enable-static --disable-shared
However, I configure is giving me the error
libgmp not found or uses a different ABI.
I built GMP with the same configure settings as above, then make, make install, etc. After this, I copied the gmp.h file and libgmp.la file to
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.3.sdk/usr/include/
and
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.3.sdk/usr/lib
respectively, but I get the same error.
Any ideas?
Okay, I think being tired got to me, and I was using an x86_64 version of GMP to try to compile the armv7 mpfr. I retried today, and everything worked. Make sure to move the gmp header and the libgmp.a file to the iOS sdk directories as mentioned in the question, else you will get an error at configure time. Other than that, it should work.

GMP Library for iOS

I have a GMP Library that is used for BIG integer calculation in C++.
I am unable to compile the same in Xcode for iOS development.
Please Provide with details steps regarding how to compile GMP for iOS Development
I realize that there has been some considerable time gone by but none of the information in the previous answer worked for me. Here is how I was able to do it, hope this helps someone else in the future.
Grab the gmp snapshot from https://gmplib.org/download/snapshot/
It is in .lz format, it will need to be uncompressed. if you have a mac, uncompress it using lzip, install with homebrew brew install lzip
Once its uncompressed from lzip, then it will be a .tar file, the finder can take care of that for you. You will have a gmp folder with a bunch of files and other sub-folders.
You will need Xcode commandline tools installed. Make sure you have that pre-installed.
Run this configure line. Take care to note that you need to put in your path to the directory you want it to be stored, in --prefix.
./configure CC="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -fembed-bitcode -arch arm64e --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS13.2.sdk" CPPFLAGS="-fembed-bitcode -arch arm64e --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS13.2.sdk " --disable-shared --enable-static --host=arm-apple-darwin --disable-assembly --prefix="{ YOUR_PATH_HERE }/GMP_6_1_99/gmp-6.1.99-20200117/gmplib-iphoneos-arm64e"
Then you run (notice the same path as before for the log files)
make -j &> "{ YOUR_PATH_HERE }/gmp-6.1.99-20200117/gmplib-iphoneos-arm64e-build.log"
make install &> "{ YOUR_PATH_HERE }/gmp-6.1.99-20200117/gmplib-iphoneos-arm64e-install.log"
There are two main points to those lines that are changeable, the platform, and the architecture. The above uses the arm64e architecture but you can just as easily build for arm64, armv7, armv7s. Also you can change out the platform as well and build for macosx, watchos, iphonesimulator, or appletvos. To change the platform you need to find the sdk of where it lives on your machine. The other architecture options are x86_64 i386, To do that, type this into your terminal...
xcrun --sdk iphoneos --show-sdk-path
(replace "iphoneos" with the platform you are looking to use from above)
And replace the SDK path. Make sure you match with the correct architecture or else you will get an error, cannot find compiler.
As GenieWanted said, provide more information!!!
However, I compiled successfully the GMP library for iOS 7 64 bits following the next step:
./configure
CC="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang"
CPP="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
-E" CPPFLAGS="-target arm64-apple-darwin -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk/
-miphoneos-version-min=7.0" --host=aarch64-apple-darwin --disable-assembly --enable-static --disable-shared --prefix=/your-path/
I would like to point out that it only creates the C library, I do not think is different for C++, however I will try this afternoon.
#bolnad's answer worked for me doing a small modification, removing the -fembed-bitcode flag both from CC and CPPFLAGS.
EDIT: it ended up not correctly compiling the different architectures, so I found this script on github https://github.com/FlowCrypt/GMP and was able to build correctly.

Strange linker error while compiling OpenCV2.3.1 on Ubuntu 11.10

I'm trying to compile OpenCV version 2.3.1 on an Ubuntu 11.10 following instructions described here. I'm getting following error. Can't understand what is happening... /usr/local/lib/libavcodec.a exists but linker can't link against it, or something else?
error:
[ 20%] Built target pch_Generate_opencv_highgui
Linking CXX shared library ../../lib/libopencv_highgui.so
/usr/bin/ld: /usr/local/lib/libavcodec.a(avpacket.o): relocation R_X86_64_32S against `av_destruct_packet'
can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/libavcodec.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
The problem is that you are attempting to link libopencv_highgui.so with libavcodec.a. The latter is built from code compiled without -fPIC (which is quite usual), and such code can not be linked into shared libraries on x86_64.
Your choices are:
Obtain libavcodec.so and arrange to link against it, or
Remove libavcodec or -lavcodec from the link line completely.
For the first, you most likely just need to install libavcodec-dev package.
If you do the second, you will still have to arrange for symbols that libopencv_highgui.so needs from libavcodec to be available at runtime. You can achieve that by linking the main executable with libavcodec (either archive or shared variant).
my take would be that, first run sudo apt-get remove libavcodec , then re-install with sudo apt-get install libopencv-dev
I once had similar issue, and the above resolved it
Running a 64-bit version of Ubuntu you have to configure and build ffmpeg with
./configure --enable-shared --enable-pic
as it is described in step 7b and 8b

How to build Boost-Libraries for iPhone

Can someone tell me, where to find a detailed guide, how to build the Boost-Libraries for using it on the iPhone-Device.
I've allready build the libs for Mac and can use them in my project (only on iPhone-Simulator). While building the project for iPhone-Device, XCode haunts me a warning: "file is not of required architecture" ond some other errors.
Please Help
Start a new project in Xcode using the iPhone Static Library project template.
Then import the source and headers, and compile it that way. The result should be an iPhone compatible static library
I started here:
http://lists.boost.org/boost-build/2009/02/21326.php
With most of Boost you probably don't need to actually compile it, just include the useful headers. In my case, I just did the compiler define in my own Xcode project.
Hey I have updated Pete Goodliffes script in my openFrameworks addon:
It currently has arm64, armv7, i386, x86_64
Boost 1.59.0 or previous
libc++ / std=c++11 -- Now optional release for libstdc++
Precompiled and Script to build yourself (so if you need libstdc++ quite easy to change)
Supports Xcode 7
[https://github.com/danoli3/ofxiOSBoost][1]
For boost libraries which have only headers files (.hpp) you can just set header search path from your project to them.
For boost libraries with sources you can build static libraries for both ios phone/simulator with next simple steps:
Download and unpack a boost release archive (from https://www.boost.org/users/download/) e.g.: https://boostorg.jfrog.io/artifactory/main/release/1.77.0/source/boost_1_77_0.tar.bz2
Run bootstrap.sh with needed libraries to build for instance 'context' (format =library1,library2,...):
./bootstrap.sh --with-libraries=context
Add toolsets with correct paths to installed SDKs to project-config.jam:
# IOS ARM64
using clang : iphoneos
: xcrun clang -arch arm64 -stdlib=libc++ -std=c++11 -miphoneos-version-min=12.0 -fvisibility-inlines-hidden -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk
;
# IOS x86_64
using clang : iphonesimulator
: xcrun clang -arch x86_64 -stdlib=libc++ -std=c++11 -miphoneos-version-min=12.0 -fvisibility-inlines-hidden -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk
;
Create and run build.sh script (where lib name is libboost_<name>.a):
lib=libboost_context.a
dir='stage/lib'
# Build arm64
./b2 -a -j4 toolset=clang-iphoneos binary-format=mach-o abi=aapcs link=static stage
mv $dir/$lib $dir/arm64_$lib
# Build x86_64
./b2 -a -j4 toolset=clang-iphonesimulator binary-format=mach-o abi=sysv link=static stage
mv $dir/$lib $dir/x86_64_$lib
# Make fat
lipo -create $dir/arm64_$lib $dir/x86_64_$lib -output $dir/$lib
Now you have next compiled static libraries in "/stage/lib" dir for boost context: arm64_libboost_context.a, x86_64_libboost_context.a and fat one libboost_context.a.
We use boost too. To simplify its inclusion into new applications I have created a Xcode project you can drop into your workspace to include boost. It is based on a Makefile so you need the Xcode commandline tools installed.
The project is here https://github.com/Cogosense/iOSBoostFramework.
Clone the project into your workspace, then click on Menu File->"Add Files to workspace". Select iOSBoostFramework/iOSBoostFramework.xcodeproj in the file finder and click add.
The Makefile in the iOSBoostFramework directory controls what is built and how it is built. There is support for Xcode workspace dependencies, bitcode generation, and only the target architectures selected by Xcode are built.
The following libraries are built test, thread, atomic, signals, filesystem, regex, program_options, system date_time, serialization, exception, locale, and random.
All the separate libraries and architectures are combined, the final build output is a FAT boost.framework Framework bundle which can be linked into the application.
The version of boost is specified in the Makefile (currently 1.64.0), it is downloaded, built for all active architectures and installed in the BUILT_PRODUCTS_DIR specified by xcode.
The previous answer helped me when I wanted to build boost for the arm simulator. When you have a Mac with M1 processor and want to use the simulator, you cannot use the arm64 build for the iPhone.
I added this to the project-config.jam:
# IOS Arm Simulator
using clang : iphonesimulatorarm64
: xcrun clang -arch arm64 -stdlib=libc++ -std=c++11 -miphoneos-version-min=10.0 -fvisibility-inlines-hidden -target arm64-apple-ios10.0-simulator -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk ;
Then pass toolset=clang-iphonesimulatorarm64 to the b2 command.

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