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
}
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`