ffmpeg

1.拉流

ffplay -i rtmp://58.200.131.2:1935/livetv/hunantv

2.流的测试地址

湖南卫视 rtmp://58.200.131.2:1935/livetv/hunantv

3.ffpmeg 的configure配置文件

Usage: configure [options]
Options: [defaults in brackets after descriptions]

# 帮助选项
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  --disable-是关闭状态 --enable是开启状态
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 最终产出的目录
  --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

Licensing options:
  --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]

Configuration options:
    #关闭静态库 然后 后面有个[no]，代表取反，意思就是开启静态库
  --disable-static         do not build static libraries [no]
  # 开启动态库 后面有给[no]  取反，意思就是关闭动态库
  --enable-shared          build shared libraries [no]
  # 优化库的大小
  --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:
    # 默认是关闭， 
  --disable-programs       do not build command line programs
  #开启就会生成ffmpeg ffplay ffprobe
  --disable-ffmpeg         disable ffmpeg build
  # 播放器
  --disable-ffplay         disable ffplay build
  --disable-ffprobe        disable ffprobe 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
  
# ffmpeg是由多个模块组成的
Component options:
  --disable-avdevice       disable libavdevice build #模块一，可以操作设备（摄像头等，Android中不支持）
  --disable-avcodec        disable libavcodec build # audio  video 的缩写av，（负责编码和解码）
  --disable-avformat       disable libavformat build    #audio  video 的格式生成和解析
  --disable-swresample     disable libswresample build #音频 重采样（可以把单声道变成双声道）
  --disable-swscale        disable libswscale build # 视频的显示相关（视频的缩放，放大、缩小）
  --disable-postproc       disable libpostproc build # 后期处理 ，用的少
  --disable-avfilter       disable libavfilter build #  给视频加水印，字幕 ，特殊效果
  --enable-avresample      enable libavresample build (deprecated) [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 #如果播放视频，不需要编码，这个就可以关闭
  --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  #混合封装（音视频等于 一段音频 一段视频 合并在一起 就是.mp4，不想这样就可以关闭）
  --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

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, libtls or mbedtls is not used [no]
  --disable-iconv          disable iconv [autodetect]
  --enable-jni             enable JNI support [no]
  --enable-ladspa          enable LADSPA audio filtering [no]
  --enable-libaom          enable AV1 video encoding/decoding via libaom [no]
  --enable-libaribb24      enable ARIB text and caption decoding via libaribb24 [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-libcodec2       enable codec2 en/decoding using libcodec2 [no]
  --enable-libdav1d        enable AV1 decoding via libdav1d [no]
  --enable-libdavs2        enable AVS2 decoding via libdavs2 [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-libjack         enable JACK audio sound server [no]
  --enable-libklvanc       enable Kernel Labs VANC processing [no]
  --enable-libkvazaar      enable HEVC encoding via libkvazaar [no]
  --enable-liblensfun      enable lensfun lens correction [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-libsrt          enable Haivision SRT protocol via libsrt [no]
  --enable-libssh          enable SFTP protocol via libssh [no]
  --enable-libtensorflow   enable TensorFlow as a DNN module backend
                           for DNN based filters like sr [no]
  --enable-libtesseract    enable Tesseract, needed for ocr filter [no]
  --enable-libtheora       enable Theora encoding via libtheora [no]
  --enable-libtls          enable LibreSSL (via libtls), needed for https support
                           if openssl, gnutls or mbedtls is not used [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-libxavs2        enable AVS2 encoding via xavs2 [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, needed
                           for dash demuxing support [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]
  --enable-lv2             enable LV2 audio filtering [no]
  --disable-lzma           disable lzma [autodetect]
  --enable-decklink        enable Blackmagic DeckLink I/O support [no]
  --enable-mbedtls         enable mbedTLS, needed for https support
                           if openssl, gnutls or libtls is not used [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 processing [no]
  --enable-opengl          enable OpenGL rendering [no]
  --enable-openssl         enable openssl, needed for https support
                           if gnutls, libtls or mbedtls is not used [no]
  --enable-pocketsphinx    enable PocketSphinx, needed for asr filter [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]
  --enable-vapoursynth     enable VapourSynth demuxer [no]
  --disable-xlib           disable xlib [autodetect]
  --disable-zlib           disable zlib [autodetect]

  The following libraries provide various hardware acceleration features:
  --disable-amf            disable AMF video encoding code [autodetect]
  --disable-audiotoolbox   disable Apple AudioToolbox code [autodetect]
  --enable-cuda-nvcc       enable Nvidia CUDA compiler [no]
  --disable-cuda-llvm      disable CUDA compilation using clang [autodetect]
  --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]
  --disable-ffnvcodec      disable dynamically linked Nvidia 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-nvdec          disable Nvidia video decoding acceleration (via hwaccel) [autodetect]
  --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-v4l2-m2m       disable V4L2 mem2mem code [autodetect]
  --disable-vaapi          disable Video Acceleration API (mainly Unix/Intel) code [autodetect]
  --disable-vdpau          disable Nvidia Video Decode and Presentation API for Unix code [autodetect]
  --disable-videotoolbox   disable VideoToolbox code [autodetect]

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
                           (gcc-asan, clang-asan, gcc-msan, clang-msan,
                           gcc-tsan, clang-tsan, gcc-usan, clang-usan,
                           valgrind-massif, valgrind-memcheck,
                           msvc, icl, gcov, llvm-cov, hardened)
  --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 or clang []
  --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-extralibs=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-ldsoflags=ELDFLAGS add ELDFLAGS to LDSOFLAGS []
  --extra-libs=ELIBS       add ELIBS []
  --extra-version=STRING   version string suffix []
  --optflags=OPTFLAGS      override optimization-related compiler flags
  --nvccflags=NVCCFLAGS    override nvcc flags []
  --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

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]

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-avx512         disable AVX-512 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-msa2           disable MSA2 optimizations
  --disable-mipsfpu        disable floating point MIPS optimizations
  --disable-mmi            disable Loongson SIMD optimizations
  --disable-fast-unaligned consider unaligned accesses slow

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-ossfuzz         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

NOTE: Object files are built at the place where configure is launched.

4.1 脚本编译 ，先安装 yum install yasm, 复制4.2中的内容可以直接运行。

#!/bin/bash
# 脚本，用于在Android中运行
# NDK路径去执行交叉编译
NDK_ROOT=/root/xiachenhui/android-ndk-r17c \
#告诉寻找所有的编译器的路径
TOOLCHAINS=/root/xiachenhui/android-ndk-r17c/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64 \
#定义当前产出的结果,目录有内容就是成功的，否则是失败了
PREFIX=./android/armeabi-v7a \
./configure \
#输出路径\代表换行,但是内容还是拼接在一起的
prefix=$PREFIX \
#优化库的大小
--enable-small \
#关闭滤镜
--disable-filters \
#关闭所有编码器(播放不需要编码) 比如摄像头
--disable-avdevice \
#关闭编码
--disable-encoders \
#关闭所有复用器(封装器) 不需要生成MP4这样的文件
--disable-muxers \
#开启交叉编译
--enable-cross-compil \
#静态库 动态库的开启关闭 ，也可以不写，是默认值
--enable-static \
--disable-shared \
# 会传给gcc的参数\
#寻找多给编译器的执行程序
--cross-prefix=$TOOLCHAINS/bin/arm-linux-androideabi- \
#交叉编译，需要另外引入平台
--sysroot=$NDK_ROOT/platforms/android-17/arch-arm \
#因为as中ndk的CMake是使用ninja操作的，必须兼容ninja才能在studio中正常使用
--extra-cflags="-isysroot $NDK_ROOT/sysroot -isystem $NDK_ROOT/sysroot/usr/include/arm-linux-androideabi -D__ANDROID_API__=17 -U_FILE_OFFSET_BITS  -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -mthumb -Wa,--noexecstack -Wformat -Werror=format-security  -O0 -fPIC" \
#指定CPU台
--arch=arm \
#指定使用平台
--target-os=android \
# 安装makefile  先清理 再安装
make clean
make
make install

4.2 编译

#!/bin/bash
NDK_ROOT=/root/xiachenhui/android-ndk-r17c
TOOLCHAINS=$NDK_ROOT/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64
PREFIX=./android/armeabi-v7a
./configure \
prefix=$PREFIX \
--enable-small \
--disable-filters \
--disable-avdevice \
--disable-encoders \
--disable-muxers \
--enable-cross-compile \
--cross-prefix=$TOOLCHAINS/bin/arm-linux-androideabi- \
--sysroot=$NDK_ROOT/platforms/android-17/arch-arm \
--extra-cflags="-isysroot $NDK_ROOT/sysroot -isystem $NDK_ROOT/sysroot/usr/include/arm-linux-androideabi -D__ANDROID_API__=17 -U_FILE_OFFSET_BITS  -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv7-a -mfloat-abi=softfp -mfpu=vfpv3-d16 -mthumb -Wa,--noexecstack -Wformat -Werror=format-security  -O0 -fPIC" \
--arch=arm \
--target-os=android
make clean
make install

5 .编译踩坑经历

1. arm-linux-androideabi-clang is unable to create an executable file.C compiler test failed.

# ffmpeg 4.2版本中configure默认的target-os是clang，需要修改为gcc
if test "$target_os" = android; then
   # cc_default="clang"
    cc_default="gcc"
fi

2. error: undefined reference to 'av_version_info()'

出错原因： ffmpeg是纯C的库，头文件没有做好C++调用的准备 用extern “C”{}套住ffmpeg头文件，用C语言的编译规则来编译ffmpeg代码，就可以了
extern "C"{
    #include <libavutil/avutil.h>
}

3. libavutil/log.c:186: error: undefined reference to 'stderr'

出错原因：

代码中使用了大量的标准IO设备：stderr 等，这些在NDK15以后，这些都不被支持了，代码本身没问题，只是编译器链接时找不到对应的静态库定义了；

解决方案：
在编译选项中添加语句-D**ANDROID_API**=[你的android API版本号]即可； 比如我的测试手机为android 5.1.1 对应 API = 22，编译选项中应该添加：-D**ANDROID_API**=22
 adb shell 获取 android 系统版本： adb shell getprop ro.build.version.release` adb shell 获取 android 系统 API 版本： `adb shell getprop ro.build.version.sdk`

4 . libavformat/utils.c:513: error: undefined reference to 'av_parser_close'

出错原因： 链接静态库先后顺序不正确，引起的符号定义找不到。

解决方案：

1. 修改静态库的链接顺序。
   target_link_libraries(
           native-lib
           avfilter avformat avcodec avutil swresample swscale
           log)


1. 忽略静态库的链接顺序。
   target_link_libraries(
           native-lib
           -Wl,--start-group
           avcodec avfilter avformat avutil swresample swscale
          -Wl,--end-group

 log)

5. libavformat/http.c:1649: error: undefined reference to 'inflateEnd

出错原因： 找不到的z库中的函数的实现。因为 ffmpeg 依赖了z库。编译ffmpeg的时候如果仔细看编译时输出的日志，就可以看到 `External libraries: zlib`
解决方案：添加z库的依赖。

target_link_libraries(
        native-lib
        -Wl,--start-group
        avcodec avfilter avformat avutil swresample swscale
        -Wl,--end-group
        log
        z
)

6. libavformat/hls.c:845: error: undefined reference to 'atof'

出错原因：
Google have moved some of the C standard library functions like atof() from being inline functions in header files to normal functions. The latest NDKs will default to building a .so that is only compatible with the latest Android devices that have the atof() function in the device's standard C library (libc.so). This means if you run a library on an older device that has an older version of the C library, you will get an error loading the dll as the expected atof() function will not exist.
解决方案： 修改ffmpeg编译脚本，指定Android API版本为17，重新编译。
这里又有一个问题：
libavcodec/v4l2_buffers.c:434:44: error: call to 'mmap' declared with attribute error: mmap is not available > with _FILE_OFFSET_BITS=64 when using GCC until android-21. Either raise your minSdkVersion, disable > _FILE_OFFSET_BITS=64, or switch to Clang.
所以21版本以下，需要取消 _FILE_OFFSET_BITS宏定义。添加编译参数： `-U_FILE_OFFSET_BITS`