这里是使用shell脚本编译FFmpeg音视频处理库

FFmpeg库下载

• 直接下载解压
  FFmpeg
• 使用shell脚本下载

###########创建shell脚本文件#################
touch ffmpeg-download.sh
chmod +x ./ffmpeg-download.sh

###########shell脚本内容#################
#!/bin/bash

#直接下载地址
#http://www.ffmpeg.org/download.html

#shell脚本下载

#库名称
source="ffmpeg-3.4"

#下载这个库
if [[ ! -r $source ]]; then
    #没有读取到库，需要下载
    echo "没有FFmpeg库， 我们需要下载。。。"


    #如何下载
    #"curl"：它可以通过http/ftp等这样的网络方式下载和上传文件（它是一个强大的网络工具）

    #基本格式：curl 地址

    #指定下载版本

    #下载完成之后，那么我们需要解压
    #tar：表示解压和压缩
    #基本语法：tar options

    #例如：tar xj
    #options选项分为很多种类型

    #-x 表示：解压文件选项
    #-j 表示：是否需要解压bz2压缩包（压缩包格式类型有很多：zip、bz2等等。。。）
    curl http://ffmpeg.org/releases/${source}.tar.bz2 | tar xj || exit 1
fi

FFmpeg库内容分析 详细文档

进入FFmpeg框架包

 ./configure --help 命令 查看配置信息

###帮助选项（输入对应指令 获取帮助信息）
Help options: 
  --help                   print this message
  --quiet                  Suppress showing informative output
  --list-decoders          show all available decoders
  --list-encoders          show all available encoders
  --list-hwaccels          show all available hardware accelerators
  --list-demuxers          show all available demuxers
  --list-muxers            show all available muxers
  --list-parsers           show all available parsers
  --list-protocols         show all available protocols
  --list-bsfs              show all available bitstream filters
  --list-indevs            show all available input devices
  --list-outdevs           show all available output devices
  --list-filters           show all available filters

###标准选项
Standard options:
  --logfile=FILE           log tests and output to FILE [ffbuild/config.log]
  --disable-logging        do not log configure debug information
  --fatal-warnings         fail if any configure warning is generated
  --prefix=PREFIX          install in PREFIX [/usr/local]
  --bindir=DIR             install binaries in DIR [PREFIX/bin]
  --datadir=DIR            install data files in DIR [PREFIX/share/ffmpeg]
  --docdir=DIR             install documentation in DIR [PREFIX/share/doc/ffmpeg]
  --libdir=DIR             install libs in DIR [PREFIX/lib]
  --shlibdir=DIR           install shared libs in DIR [LIBDIR]
  --incdir=DIR             install includes in DIR [PREFIX/include]
  --mandir=DIR             install man page in DIR [PREFIX/share/man]
  --pkgconfigdir=DIR       install pkg-config files in DIR [LIBDIR/pkgconfig]
  --enable-rpath           use rpath to allow installing libraries in paths
                           not part of the dynamic linker search path
                           use rpath when linking programs (USE WITH CARE)
  --install-name-dir=DIR   Darwin directory name for installed targets

###许可选项（侵权）
Licensing options:

允许使用GPL代码，由此生成你自己的库和二进制文件
gpl(许可证):开源、免费、公用、修改、扩展
  --enable-gpl             allow use of GPL code, the resulting libs
                           and binaries will be under GPL [no]
  --enable-version3        upgrade (L)GPL to version 3 [no]
  --enable-nonfree         allow use of nonfree code, the resulting libs
                           and binaries will be unredistributable [no]

###配置选项
Configuration options:
  --disable-static         do not build static libraries [no]
  --enable-shared          build shared libraries [no]
  --enable-small           optimize for size instead of speed
  --disable-runtime-cpudetect disable detecting CPU capabilities at runtime (smaller binary)
  --enable-gray            enable full grayscale support (slower color)
  --disable-swscale-alpha  disable alpha channel support in swscale
  --disable-all            disable building components, libraries and programs
  --disable-autodetect     disable automatically detected external libraries [no]

Program options:
  --disable-programs       do not build command line programs
  --disable-ffmpeg         disable ffmpeg build
  --disable-ffplay         disable ffplay build
  --disable-ffprobe        disable ffprobe build
  --disable-ffserver       disable ffserver build

Documentation options:
  --disable-doc            do not build documentation
  --disable-htmlpages      do not build HTML documentation pages
  --disable-manpages       do not build man documentation pages
  --disable-podpages       do not build POD documentation pages
  --disable-txtpages       do not build text documentation pages

Component options:
  --disable-avdevice       disable libavdevice build
  --disable-avcodec        disable libavcodec build
  --disable-avformat       disable libavformat build
  --disable-swresample     disable libswresample build
  --disable-swscale        disable libswscale build
  --disable-postproc       disable libpostproc build
  --disable-avfilter       disable libavfilter build
  --enable-avresample      enable libavresample build [no]
  --disable-pthreads       disable pthreads [autodetect]
  --disable-w32threads     disable Win32 threads [autodetect]
  --disable-os2threads     disable OS/2 threads [autodetect]
  --disable-network        disable network support [no]
  --disable-dct            disable DCT code
  --disable-dwt            disable DWT code
  --disable-error-resilience disable error resilience code
  --disable-lsp            disable LSP code
  --disable-lzo            disable LZO decoder code
  --disable-mdct           disable MDCT code
  --disable-rdft           disable RDFT code
  --disable-fft            disable FFT code
  --disable-faan           disable floating point AAN (I)DCT code
  --disable-pixelutils     disable pixel utils in libavutil

Individual component options:
  --disable-everything     disable all components listed below
  --disable-encoder=NAME   disable encoder NAME
  --enable-encoder=NAME    enable encoder NAME
  --disable-encoders       disable all encoders
  --disable-decoder=NAME   disable decoder NAME
  --enable-decoder=NAME    enable decoder NAME
  --disable-decoders       disable all decoders
  --disable-hwaccel=NAME   disable hwaccel NAME
  --enable-hwaccel=NAME    enable hwaccel NAME
  --disable-hwaccels       disable all hwaccels
  --disable-muxer=NAME     disable muxer NAME
  --enable-muxer=NAME      enable muxer NAME
  --disable-muxers         disable all muxers
  --disable-demuxer=NAME   disable demuxer NAME
  --enable-demuxer=NAME    enable demuxer NAME
  --disable-demuxers       disable all demuxers
  --enable-parser=NAME     enable parser NAME
  --disable-parser=NAME    disable parser NAME
  --disable-parsers        disable all parsers
  --enable-bsf=NAME        enable bitstream filter NAME
  --disable-bsf=NAME       disable bitstream filter NAME
  --disable-bsfs           disable all bitstream filters
  --enable-protocol=NAME   enable protocol NAME
  --disable-protocol=NAME  disable protocol NAME
  --disable-protocols      disable all protocols
  --enable-indev=NAME      enable input device NAME
  --disable-indev=NAME     disable input device NAME
  --disable-indevs         disable input devices
  --enable-outdev=NAME     enable output device NAME
  --disable-outdev=NAME    disable output device NAME
  --disable-outdevs        disable output devices
  --disable-devices        disable all devices
  --enable-filter=NAME     enable filter NAME
  --disable-filter=NAME    disable filter NAME
  --disable-filters        disable all filters
  --disable-v4l2_m2m       disable V4L2 mem2mem code [autodetect]

###外部看支持-->使用ffmpeg重点
External library support:

  Using any of the following switches will allow FFmpeg to link to the
  corresponding external library. All the components depending on that library
  will become enabled, if all their other dependencies are met and they are not
  explicitly disabled. E.g. --enable-libwavpack will enable linking to
  libwavpack and allow the libwavpack encoder to be built, unless it is
  specifically disabled with --disable-encoder=libwavpack.

  Note that only the system libraries are auto-detected. All the other external
  libraries must be explicitly enabled.

  Also note that the following help text describes the purpose of the libraries
  themselves, not all their features will necessarily be usable by FFmpeg.

  --disable-alsa           disable ALSA support [autodetect]
  --disable-appkit         disable Apple AppKit framework [autodetect]
  --disable-avfoundation   disable Apple AVFoundation framework [autodetect]
  --enable-avisynth        enable reading of AviSynth script files [no]
  --disable-bzlib          disable bzlib [autodetect]
  --disable-coreimage      disable Apple CoreImage framework [autodetect]
  --enable-chromaprint     enable audio fingerprinting with chromaprint [no]
  --enable-frei0r          enable frei0r video filtering [no]
  --enable-gcrypt          enable gcrypt, needed for rtmp(t)e support
                           if openssl, librtmp or gmp is not used [no]
  --enable-gmp             enable gmp, needed for rtmp(t)e support
                           if openssl or librtmp is not used [no]
  --enable-gnutls          enable gnutls, needed for https support
                           if openssl is not used [no]
  --disable-iconv          disable iconv [autodetect]
  --disable-jack           disable libjack support [autodetect]
  --enable-jni             enable JNI support [no]
  --enable-ladspa          enable LADSPA audio filtering [no]
  --enable-libass          enable libass subtitles rendering,
                           needed for subtitles and ass filter [no]
  --enable-libbluray       enable BluRay reading using libbluray [no]
  --enable-libbs2b         enable bs2b DSP library [no]
  --enable-libcaca         enable textual display using libcaca [no]
  --enable-libcelt         enable CELT decoding via libcelt [no]
  --enable-libcdio         enable audio CD grabbing with libcdio [no]
  --enable-libdc1394       enable IIDC-1394 grabbing using libdc1394
                           and libraw1394 [no]
  --enable-libfdk-aac      enable AAC de/encoding via libfdk-aac [no]
  --enable-libflite        enable flite (voice synthesis) support via libflite [no]
  --enable-libfontconfig   enable libfontconfig, useful for drawtext filter [no]
  --enable-libfreetype     enable libfreetype, needed for drawtext filter [no]
  --enable-libfribidi      enable libfribidi, improves drawtext filter [no]
  --enable-libgme          enable Game Music Emu via libgme [no]
  --enable-libgsm          enable GSM de/encoding via libgsm [no]
  --enable-libiec61883     enable iec61883 via libiec61883 [no]
  --enable-libilbc         enable iLBC de/encoding via libilbc [no]
  --enable-libkvazaar      enable HEVC encoding via libkvazaar [no]
  --enable-libmodplug      enable ModPlug via libmodplug [no]
  --enable-libmp3lame      enable MP3 encoding via libmp3lame [no]
  --enable-libopencore-amrnb enable AMR-NB de/encoding via libopencore-amrnb [no]
  --enable-libopencore-amrwb enable AMR-WB decoding via libopencore-amrwb [no]
  --enable-libopencv       enable video filtering via libopencv [no]
  --enable-libopenh264     enable H.264 encoding via OpenH264 [no]
  --enable-libopenjpeg     enable JPEG 2000 de/encoding via OpenJPEG [no]
  --enable-libopenmpt      enable decoding tracked files via libopenmpt [no]
  --enable-libopus         enable Opus de/encoding via libopus [no]
  --enable-libpulse        enable Pulseaudio input via libpulse [no]
  --enable-librsvg         enable SVG rasterization via librsvg [no]
  --enable-librubberband   enable rubberband needed for rubberband filter [no]
  --enable-librtmp         enable RTMP[E] support via librtmp [no]
  --enable-libshine        enable fixed-point MP3 encoding via libshine [no]
  --enable-libsmbclient    enable Samba protocol via libsmbclient [no]
  --enable-libsnappy       enable Snappy compression, needed for hap encoding [no]
  --enable-libsoxr         enable Include libsoxr resampling [no]
  --enable-libspeex        enable Speex de/encoding via libspeex [no]
  --enable-libssh          enable SFTP protocol via libssh [no]
  --enable-libtesseract    enable Tesseract, needed for ocr filter [no]
  --enable-libtheora       enable Theora encoding via libtheora [no]
  --enable-libtwolame      enable MP2 encoding via libtwolame [no]
  --enable-libv4l2         enable libv4l2/v4l-utils [no]
  --enable-libvidstab      enable video stabilization using vid.stab [no]
  --enable-libvmaf         enable vmaf filter via libvmaf [no]
  --enable-libvo-amrwbenc  enable AMR-WB encoding via libvo-amrwbenc [no]
  --enable-libvorbis       enable Vorbis en/decoding via libvorbis,
                           native implementation exists [no]
  --enable-libvpx          enable VP8 and VP9 de/encoding via libvpx [no]
  --enable-libwavpack      enable wavpack encoding via libwavpack [no]
  --enable-libwebp         enable WebP encoding via libwebp [no]
  --enable-libx264         enable H.264 encoding via x264 [no]
  --enable-libx265         enable HEVC encoding via x265 [no]
  --enable-libxavs         enable AVS encoding via xavs [no]
  --enable-libxcb          enable X11 grabbing using XCB [autodetect]
  --enable-libxcb-shm      enable X11 grabbing shm communication [autodetect]
  --enable-libxcb-xfixes   enable X11 grabbing mouse rendering [autodetect]
  --enable-libxcb-shape    enable X11 grabbing shape rendering [autodetect]
  --enable-libxvid         enable Xvid encoding via xvidcore,
                           native MPEG-4/Xvid encoder exists [no]
  --enable-libxml2         enable XML parsing using the C library libxml2 [no]
  --enable-libzimg         enable z.lib, needed for zscale filter [no]
  --enable-libzmq          enable message passing via libzmq [no]
  --enable-libzvbi         enable teletext support via libzvbi [no]
  --disable-lzma           disable lzma [autodetect]
  --enable-decklink        enable Blackmagic DeckLink I/O support [no]
  --enable-libndi_newtek   enable Newteck NDI I/O support [no]
  --enable-mediacodec      enable Android MediaCodec support [no]
  --enable-libmysofa       enable libmysofa, needed for sofalizer filter [no]
  --enable-openal          enable OpenAL 1.1 capture support [no]
  --enable-opencl          enable OpenCL code
  --enable-opengl          enable OpenGL rendering [no]
  --enable-openssl         enable openssl, needed for https support
                           if gnutls is not used [no]
  --disable-sndio          disable sndio support [autodetect]
  --disable-schannel       disable SChannel SSP, needed for TLS support on
                           Windows if openssl and gnutls are not used [autodetect]
  --disable-sdl2           disable sdl2 [autodetect]
  --disable-securetransport disable Secure Transport, needed for TLS support
                           on OSX if openssl and gnutls are not used [autodetect]
  --disable-xlib           disable xlib [autodetect]
  --disable-zlib           disable zlib [autodetect]

  The following libraries provide various hardware acceleration features:
  --disable-audiotoolbox   disable Apple AudioToolbox code [autodetect]
  --disable-cuda           disable dynamically linked Nvidia CUDA code [autodetect]
  --enable-cuda-sdk        enable CUDA features that require the CUDA SDK [no]
  --disable-cuvid          disable Nvidia CUVID support [autodetect]
  --disable-d3d11va        disable Microsoft Direct3D 11 video acceleration code [autodetect]
  --disable-dxva2          disable Microsoft DirectX 9 video acceleration code [autodetect]
  --enable-libdrm          enable DRM code (Linux) [no]
  --enable-libmfx          enable Intel MediaSDK (AKA Quick Sync Video) code via libmfx [no]
  --enable-libnpp          enable Nvidia Performance Primitives-based code [no]
  --enable-mmal            enable Broadcom Multi-Media Abstraction Layer (Raspberry Pi) via MMAL [no]
  --disable-nvenc          disable Nvidia video encoding code [autodetect]
  --enable-omx             enable OpenMAX IL code [no]
  --enable-omx-rpi         enable OpenMAX IL code for Raspberry Pi [no]
  --enable-rkmpp           enable Rockchip Media Process Platform code [no]
  --disable-vaapi          disable Video Acceleration API (mainly Unix/Intel) code [autodetect]
  --disable-vda            disable Apple Video Decode Acceleration code [autodetect]
  --disable-vdpau          disable Nvidia Video Decode and Presentation API for Unix code [autodetect]
  --disable-videotoolbox   disable VideoToolbox code [autodetect]

###工具链选项（指定我们需要编译平台CPU架构类型，列如：arm64、x86等等...）
Toolchain options:
  --arch=ARCH              select architecture []
  --cpu=CPU                select the minimum required CPU (affects
                           instruction selection, may crash on older CPUs)
  --cross-prefix=PREFIX    use PREFIX for compilation tools []
  --progs-suffix=SUFFIX    program name suffix []
  --enable-cross-compile   assume a cross-compiler is used
  --sysroot=PATH           root of cross-build tree
  --sysinclude=PATH        location of cross-build system headers
  --target-os=OS           compiler targets OS []
  --target-exec=CMD        command to run executables on target
  --target-path=DIR        path to view of build directory on target
  --target-samples=DIR     path to samples directory on target
  --tempprefix=PATH        force fixed dir/prefix instead of mktemp for checks
  --toolchain=NAME         set tool defaults according to NAME
  --nm=NM                  use nm tool NM [nm -g]
  --ar=AR                  use archive tool AR [ar]
  --as=AS                  use assembler AS []
  --ln_s=LN_S              use symbolic link tool LN_S [ln -s -f]
  --strip=STRIP            use strip tool STRIP [strip]
  --windres=WINDRES        use windows resource compiler WINDRES [windres]
  --x86asmexe=EXE          use nasm-compatible assembler EXE [nasm]
  --cc=CC                  use C compiler CC [gcc]
  --cxx=CXX                use C compiler CXX [g++]
  --objcc=OCC              use ObjC compiler OCC [gcc]
  --dep-cc=DEPCC           use dependency generator DEPCC [gcc]
  --nvcc=NVCC              use Nvidia CUDA compiler NVCC [nvcc]
  --ld=LD                  use linker LD []
  --pkg-config=PKGCONFIG   use pkg-config tool PKGCONFIG [pkg-config]
  --pkg-config-flags=FLAGS pass additional flags to pkgconf []
  --ranlib=RANLIB          use ranlib RANLIB [ranlib]
  --doxygen=DOXYGEN        use DOXYGEN to generate API doc [doxygen]
  --host-cc=HOSTCC         use host C compiler HOSTCC
  --host-cflags=HCFLAGS    use HCFLAGS when compiling for host
  --host-cppflags=HCPPFLAGS use HCPPFLAGS when compiling for host
  --host-ld=HOSTLD         use host linker HOSTLD
  --host-ldflags=HLDFLAGS  use HLDFLAGS when linking for host
  --host-libs=HLIBS        use libs HLIBS when linking for host
  --host-os=OS             compiler host OS []
  --extra-cflags=ECFLAGS   add ECFLAGS to CFLAGS []
  --extra-cxxflags=ECFLAGS add ECFLAGS to CXXFLAGS []
  --extra-objcflags=FLAGS  add FLAGS to OBJCFLAGS []
  --extra-ldflags=ELDFLAGS add ELDFLAGS to LDFLAGS []
  --extra-ldexeflags=ELDFLAGS add ELDFLAGS to LDEXEFLAGS []
  --extra-ldlibflags=ELDFLAGS add ELDFLAGS to LDLIBFLAGS []
  --extra-libs=ELIBS       add ELIBS []
  --extra-version=STRING   version string suffix []
  --optflags=OPTFLAGS      override optimization-related compiler flags
  --nvccflags=NVCCFLAGS    override nvcc flags [-gencode arch=compute_30,code=sm_30 -O2]
  --build-suffix=SUFFIX    library name suffix []
  --enable-pic             build position-independent code
  --enable-thumb           compile for Thumb instruction set
  --enable-lto             use link-time optimization
  --env="ENV=override"     override the environment variables

###高级选项
Advanced options (experts only):
  --malloc-prefix=PREFIX   prefix malloc and related names with PREFIX
  --custom-allocator=NAME  use a supported custom allocator
  --disable-symver         disable symbol versioning
  --enable-hardcoded-tables use hardcoded tables instead of runtime generation
  --disable-safe-bitstream-reader
                           disable buffer boundary checking in bitreaders
                           (faster, but may crash)
  --sws-max-filter-size=N  the max filter size swscale uses [256]

###优化选项
Optimization options (experts only):
  --disable-asm            disable all assembly optimizations
  --disable-altivec        disable AltiVec optimizations
  --disable-vsx            disable VSX optimizations
  --disable-power8         disable POWER8 optimizations
  --disable-amd3dnow       disable 3DNow! optimizations
  --disable-amd3dnowext    disable 3DNow! extended optimizations
  --disable-mmx            disable MMX optimizations
  --disable-mmxext         disable MMXEXT optimizations
  --disable-sse            disable SSE optimizations
  --disable-sse2           disable SSE2 optimizations
  --disable-sse3           disable SSE3 optimizations
  --disable-ssse3          disable SSSE3 optimizations
  --disable-sse4           disable SSE4 optimizations
  --disable-sse42          disable SSE4.2 optimizations
  --disable-avx            disable AVX optimizations
  --disable-xop            disable XOP optimizations
  --disable-fma3           disable FMA3 optimizations
  --disable-fma4           disable FMA4 optimizations
  --disable-avx2           disable AVX2 optimizations
  --disable-aesni          disable AESNI optimizations
  --disable-armv5te        disable armv5te optimizations
  --disable-armv6          disable armv6 optimizations
  --disable-armv6t2        disable armv6t2 optimizations
  --disable-vfp            disable VFP optimizations
  --disable-neon           disable NEON optimizations
  --disable-inline-asm     disable use of inline assembly
  --disable-x86asm         disable use of standalone x86 assembly
  --disable-mipsdsp        disable MIPS DSP ASE R1 optimizations
  --disable-mipsdspr2      disable MIPS DSP ASE R2 optimizations
  --disable-msa            disable MSA optimizations
  --disable-mipsfpu        disable floating point MIPS optimizations
  --disable-mmi            disable Loongson SIMD optimizations
  --disable-fast-unaligned consider unaligned accesses slow

###开发者选项
Developer options (useful when working on FFmpeg itself):
  --disable-debug          disable debugging symbols
  --enable-debug=LEVEL     set the debug level []
  --disable-optimizations  disable compiler optimizations
  --enable-extra-warnings  enable more compiler warnings
  --disable-stripping      disable stripping of executables and shared libraries
  --assert-level=level     0(default), 1 or 2, amount of assertion testing,
                           2 causes a slowdown at runtime.
  --enable-memory-poisoning fill heap uninitialized allocated space with arbitrary data
  --valgrind=VALGRIND      run "make fate" tests through valgrind to detect memory
                           leaks and errors, using the specified valgrind binary.
                           Cannot be combined with --target-exec
  --enable-ftrapv          Trap arithmetic overflows
  --samples=PATH           location of test samples for FATE, if not set use
                           $FATE_SAMPLES at make invocation time.
  --enable-neon-clobber-test check NEON registers for clobbering (should be
                           used only for debugging purposes)
  --enable-xmm-clobber-test check XMM registers for clobbering (Win64-only;
                           should be used only for debugging purposes)
  --enable-random          randomly enable/disable components
  --disable-random
  --enable-random=LIST     randomly enable/disable specific components or
  --disable-random=LIST    component groups. LIST is a comma-separated list
                           of NAME[:PROB] entries where NAME is a component
                           (group) and PROB the probability associated with
                           NAME (default 0.5).
  --random-seed=VALUE      seed value for --enable/disable-random
  --disable-valgrind-backtrace do not print a backtrace under Valgrind
                           (only applies to --disable-optimizations builds)
  --enable-osfuzz          Enable building fuzzer tool
  --libfuzzer=PATH         path to libfuzzer
  --ignore-tests=TESTS     comma-separated list (without "fate-" prefix
                           in the name) of tests whose result is ignored
  --enable-linux-perf      enable Linux Performance Monitor API

FFmpeg-iOS库编译

熟悉上面的配置项，然后开始编写我们的shell脚本

#!/bin/bash

#1、首先：定义下载的库名称
source="ffmpeg-3.4"

#2、其次：定义".h/.m/.c"文件编译的结果目录
#目录作用：用于保存.h/.m/.c文件编译后的结果.o文件
cache="cache"

#3、定义".a"静态库保存目录
#pwd命令：表示获取当前目录
staticdir=`pwd`/"dream-ffmpeg-iOS"

#4、添加FFmpeg配置选项->默认配置
#Toolchain options:工具链选项（指定我么需要编译平台CPU架构类型，例如：arm64、x86等等…）
#--enable-cross-compile: 交叉编译
#Developer options:开发者选项
#--disable-debug: 禁止使用调试模式
#Program options选项
#--disable-programs:禁用程序(不允许建立命令行程序)
#Documentation options：文档选项
#--disable-doc：不需要编译文档
#Toolchain options：工具链选项
#--enable-pic：允许建立与位置无关代码
configure_flags="--enable-cross-compile --disable-debug --disable-programs --disable-doc --enable-pic"

#5、定义默认CPU平台架构类型
#arm64 armv7->真机->CPU架构类型
#x86_64 i386->模拟器->CPU架构类型
archs="arm64 armv7 x86_64 i386"

#6、指定我们的这个库编译系统版本->iOS系统下的7.0以及以上版本使用这个静态库
targetversion="7.0"

#7、接受命令后输入参数
#我是动态接受命令行输入CPU平台架构类型(输入参数：编译指定的CPU库)
if [ "$*" ]
then
    #存在输入参数，也就说：外部指定需要编译CPU架构类型
    archs="$*"
fi

#8、安装汇编器->yasm
#判断一下是否存在这个汇编器
#目的：通过软件管理器(Homebrew)，然后下载安装（或者更新）我的汇编器
#一个命令就能够帮助我们完成所有的操作
#错误一：`which` yasm
#正确一：`which yasm`
if [ ! `which yasm`  ]
then
    #Homebrew:软件管理器
    #下载一个软件管理器:安装、卸载、更新、搜索等等...
    #错误二：`which` brew
    #正确二：`which brew`
    if [ ! `which brew` ]
    then
        echo "安装brew"
        ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" || exit 1
    fi
    echo "安装yasm"
    #成功了
    #下载安装这个汇编器
    #exit 1->安装失败了，那么退出程序
    brew install yasm || exit 1
fi

echo "循环编译"

#9、for循环编译FFmpeg静态库
currentdir=`pwd`
for arch in $archs
do
    echo "开始编译"
    #9.1、创建目录
    #在编译结果目录下-创建对应的平台架构类型
    mkdir -p "$cache/$arch"
    #9.2、进入这个目录
    cd "$cache/$arch"

    #9.3、配置编译CPU架构类型->指定当前编译CPU架构类型
    #错误三："--arch $arch"
    #正确三："-arch $arch"
    archflags="-arch $arch"

    #9.4、判定一下你到底是编译的是模拟器.a静态库，还是真机.a静态库
    if [ "$arch" = "i386" -o "$arch" = "x86_64" ]
    then
        #模拟器
        platform="iPhoneSimulator"
        #支持最小系统版本->iOS系统
        archflags="$archflags -mios-simulator-version-min=$targetversion"
    else
        #真机(mac、iOS都支持)
        platform="iPhoneOS"
        #支持最小系统版本->iOS系统
        archflags="$archflags -mios-version-min=$targetversion -fembed-bitcode"
        #注意:优化处理(可有可无)
        #如果架构类型是"arm64"，那么
        if [ "$arch" = "arm64" ]
        then
            #GNU汇编器（GNU Assembler），简称为GAS
            #GASPP->汇编器预处理程序
            #解决问题：分段错误
            #通俗一点：就是程序运行时,变量访问越界一类的问题
            EXPORT="GASPP_FIX_XCODE5=1"
        fi
    fi


    #10、正式编译
    #tr命令可以对来自标准输入的字符进行替换、压缩和删除
    #'[:upper:]'->将小写转成大写
    #'[:lower:]'->将大写转成小写
    #将platform->转成大写或者小写
    XCRUN_SDK=`echo $platform | tr '[:upper:]' '[:lower:]'`
    #编译器->编译平台
    CC="xcrun -sdk $XCRUN_SDK clang"

    #架构类型->arm64
    if [ "$arch" = "arm64" ]
    then
        #音视频默认一个编译命令
        #preprocessor.pl帮助我们编译FFmpeg->arm64位静态库
        AS="gas-preprocessor.pl -arch aarch64 -- $CC"
    else
        #默认编译平台
        AS="$CC"
    fi

    echo "执行到了1"

    #目录找到FFmepg编译源代码目录->设置编译配置->编译FFmpeg源码
    #--target-os:目标系统->darwin(mac系统早起版本名字)
    #darwin:是mac系统、iOS系统祖宗
    #--arch:CPU平台架构类型
    #--cc：指定编译器类型选项
    #--as:汇编程序
    #$configure_flags最初配置
    #--extra-cflags
    #--prefix：静态库输出目录
    TMPDIR=${TMPDIR/%\/} $currentdir/$source/configure \
        --target-os=darwin \
        --arch=$arch \
        --cc="$CC" \
        --as="$AS" \
        $configure_flags \
        --extra-cflags="$archflags" \
        --extra-ldflags="$archflags" \
        --prefix="$staticdir/$arch" \
        || exit 1

    echo "执行了"

    #解决问题->分段错误问题
    #安装->导出静态库(编译.a静态库)
    #执行命令
    make -j3 install $EXPORT || exit 1
    #回到了我们的脚本文件目录
    cd $currentdir
done

gas-preprocessor编译ffmpeg所需要的脚本文件
将gas-preprocessor.pl拷贝到 /usr/local/bin目录下
执行chmod 777 /usr/local/bin/gas-preprocessor.pl

./ffmpeg-build.sh执行脚本

等待十几分钟，获取我们的编译库

image.png

cache:用于保存.h/.m/.c文件编译后的结果.o文件,
yochi-ffmpeg-iOS".a"静态库保存目录

FFmpeg-Android库编译

安卓使用FFmpeg库需要搭建NDK环境
NDK下载

终端解压：
Mac解压NDK . bin文件 记得替换为你下载的文件名
1.获取文件权限
chmod a+x android-ndk-r10c-darwin-x86_64.bin
2. 解压出文件
./android-ndk-r10c-darwin-x86_64.bin

编译.so动态库文件 注意提花NDK路径

#!/bin/bash

#第一步：进入到指定目录
cd ffmpeg-3.4

#第二步：指定NDK路径(编译什么样的平台->采用什么样的平台编译器)
#Android平台NDK技术->做C/C++开发->编译Andrroid平台下.so动态库
#注意：放在英文目录(中文目录报错)
#修改一：修改为你自己NDK存放目录
NDK_DIR=/Users/chmtech003/Desktop/GitHub项目/Yochi_FFmpeg/Android/NDKPackage/android-ndk-r10e

#第三步：配置Android系统版本(支持最小的版本)
#指定使用NDK Platform版本(对应系统版本)
SYSROOT=$NDK_DIR/platforms/android-18/arch-arm

#第四步：指定编译工具链->(通俗：指定编译器)->CPU架构（Android手机通用的CPU架构类型）：armeabi
TOOLCHAIN=$NDK_DIR/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64

#第五步：指定CPU平台架构类型
#指定编译后的安装目录
ARCH=arm
ADDI_CFLAGS="-marm"

#第六步：指定编译成功之后，.so动态库存放位置
#修改二：这个目录你需要修改为你自己目录
PREFIX=/Users/chmtech003/Desktop/GitHub项目/Yochi_FFmpeg/Android/ffmpeg-android/android-build/$ARCH

#第七步：编写执行编译脚本->调用FFmpeg进行配置
#定义了Shell脚本函数(方法)
function build_armeabi
{
./configure \
--prefix=$PREFIX \
--enable-shared \
--enable-gpl \
--disable-static \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-ffserver \
--disable-doc \
--disable-symver \
--enable-small \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
--target-os=android \
--arch=$ARCH \
--enable-cross-compile \
--sysroot=$SYSROOT \
--extra-cflags="-Os -fpic $ADDI_CFLAGS" \
--enable-pic \
$ADDITIONAL_CONFIGURE_FLAG

make clean
make -j4
make install
}

#第八步：执行函数->开始编译
build_armeabi
echo "Android armeabi builds finished"

注意事项，处理之前：目标编译出来.so动态库格式
libavcodec.so.57.2.100
存在问题：你在Android程序中无法加载动态库，编译器报错（报错信息：找不到这个动态库），及时你修改了后缀名为libavcodec.so，依然还是无法运行，此处是坑
处理之后：.so动态库格式：libavcodec.so

解决方案
        首先：进入FFmpeg-3.4开发包
        其次：打开configure文件
        最后：修改配置

原始
            #SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
            #LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
            #SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
            #SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'

修改
            SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
            LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
            SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
            SLIB_INSTALL_LINKS='$(SLIBNAME)'

再次执行脚本
 ./build-ffmpeg-armeabi.sh（这个是我的脚本文件名称哦）

脚本下载：https://github.com/iyouqiang/FFmpeg_Script.git

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