ffmpeg编译裁剪移植到arm-linux
源码裁剪参考：
ffmpeg源码裁剪移植到arm-linux
ffmpeg可以通过配置不同的编译选项来裁剪ffmpeg本身的大小，下面我基于2.1.3版本来说明。
至于支持哪些编译选项，可输入 ./configure --help 查看，如下：
Usage: configure [options]
Options: [defaults in brackets after descriptions]
Help options:
--help print this message
--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
Standard options:
--logfile=FILE log tests and output to FILE [config.log]
--disable-logging do not log configure debug information
--fatal-warnings fail if any configure warning is generated
--prefix=PREFIX install in PREFIX []
--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 [PREFIX/lib]
--incdir=DIR install includes in DIR [PREFIX/include]
--mandir=DIR install man page in DIR [PREFIX/share/man]
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:
--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
--enable-incompatible-libav-abi enable incompatible Libav fork ABI [no]
--enable-incompatible-fork-abi enable incompatible Libav fork ABI (deprecated) [no]
--enable-raise-major increase major version numbers in sonames [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-avutil disable libavutil 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 [auto]
--disable-w32threads disable Win32 threads [auto]
--disable-os2threads disable OS/2 threads [auto]
--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
Hardware accelerators:
--disable-dxva2 disable DXVA2 code [autodetect]
--disable-vaapi disable VAAPI code [autodetect]
--enable-vda enable VDA code
--disable-vdpau disable VDPAU code [autodetect]
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
External library support:
--enable-avisynth enable reading of AviSynth script files [no]
--disable-bzlib disable bzlib [autodetect]
--enable-fontconfig enable fontconfig
--enable-frei0r enable frei0r video filtering
--enable-gnutls enable gnutls [no]
--disable-iconv disable iconv [autodetect]
--enable-ladspa enable LADSPA audio filtering
--enable-libaacplus enable AAC+ encoding via libaacplus [no]
--enable-libass enable libass subtitles rendering [no]
--enable-libbluray enable BluRay reading using libbluray [no]
--enable-libcaca enable textual display using libcaca
--enable-libcelt enable CELT decoding via libcelt [no]
--enable-libcdio enable audio CD grabbing with libcdio
--enable-libdc1394 enable IIDC-1394 grabbing using libdc1394
and libraw1394 [no]
--enable-libfaac enable AAC encoding via libfaac [no]
--enable-libfdk-aac enable AAC de/encoding via libfdk-aac [no]
--enable-libflite enable flite (voice synthesis) support via libflite [no]
--enable-libfreetype enable libfreetype [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-libmodplug enable ModPlug via libmodplug [no]
--enable-libmp3lame enable MP3 encoding via libmp3lame [no]
--enable-libnut enable NUT (de)muxing via libnut,
native (de)muxer exists [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-libopenjpeg enable JPEG 2000 de/encoding via OpenJPEG [no]
--enable-libopus enable Opus decoding via libopus [no]
--enable-libpulse enable Pulseaudio input via libpulse [no]
--enable-libquvi enable quvi input via libquvi [no]
--enable-librtmp enable RTMP[E] support via librtmp [no]
--enable-libschroedinger enable Dirac de/encoding via libschroedinger [no]
--enable-libshine enable fixed-point MP3 encoding via libshine [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-libstagefright-h264 enable H.264 decoding via libstagefright [no]
--enable-libtheora enable Theora encoding via libtheora [no]
--enable-libtwolame enable MP2 encoding via libtwolame [no]
--enable-libutvideo enable Ut Video encoding and decoding via libutvideo [no]
--enable-libv4l2 enable libv4l2/v4l-utils [no]
--enable-libvidstab enable video stabilization using vid.stab [no]
--enable-libvo-aacenc enable AAC encoding via libvo-aacenc [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-libx264 enable H.264 encoding via x264 [no]
--enable-libxavs enable AVS encoding via xavs [no]
--enable-libxvid enable Xvid encoding via xvidcore,
native MPEG-4/Xvid encoder exists [no]
--enable-libzmq enable message passing via libzmq [no]
--enable-libzvbi enable teletext support via libzvbi [no]
--enable-openal enable OpenAL 1.1 capture support [no]
--enable-opencl enable OpenCL code
--enable-openssl enable openssl [no]
--enable-x11grab enable X11 grabbing [no]
--disable-zlib disable zlib [autodetect]
Advanced options (experts only):
--cross-prefix=PREFIX use PREFIX for compilation tools []
--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 []
--yasmexe=EXE use yasm-compatible assembler EXE [yasm]
--cc=CC use C compiler CC [gcc]
--cxx=CXX use C compiler CXX [g++]
--dep-cc=DEPCC use dependency generator DEPCC [gcc]
--ld=LD use linker LD []
--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-ldflags=ELDFLAGS add ELDFLAGS to LDFLAGS []
--extra-libs=ELIBS add ELIBS []
--extra-version=STRING version string suffix []
--optflags=OPTFLAGS override optimization-related compiler flags
--build-suffix=SUFFIX library name suffix []
--malloc-prefix=PREFIX prefix malloc and related names with PREFIX
--progs-suffix=SUFFIX program name suffix []
--arch=ARCH select architecture []
--cpu=CPU select the minimum required CPU (affects
instruction selection, may crash on older CPUs)
--enable-pic build position-independent code
--enable-sram allow use of on-chip SRAM
--enable-thumb compile for Thumb instruction set
--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)
--enable-memalign-hack emulate memalign, interferes with memory debuggers
--enable-lto use link-time optimization
Optimization options (experts only):
--disable-asm disable all assembler optimizations
--disable-altivec disable AltiVec 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-fma4 disable FMA4 optimizations
--disable-avx2 disable AVX2 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-vis disable VIS optimizations
--disable-inline-asm disable use of inline assembler
--disable-yasm disable use of yasm assembler
--disable-mips32r2 disable MIPS32R2 optimizations
--disable-mipsdspr1 disable MIPS DSP ASE R1 optimizations
--disable-mipsdspr2 disable MIPS DSP ASE R2 optimizations
--disable-mipsfpu disable floating point MIPS 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-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
NOTE: Object files are built at the place where configure is launched.帮助介绍得很详细，我就不一一叙述了，主要提一下注意的点：
所有的enable/disable选项都有默认值， 列出来的选项内容如果是
--enable-xxx ：说明默认是禁止的
--disable-xxx：说明默认是使能的
（PS: 当然有些选项说明后面也提示了 [NO] 来说明默认禁止）
--disable-all： disable building components, libraries and programs（加了这个选项后，所有库，执行文件都不会生成）
--disable-everything：disable all components listed below（加了这个选项，encoder，decoder，muxer，demuxer，protocol等等都不会编入库中）
基于上述两个选项，我们可以这么做：
首先--disable-all 禁止所有东西，然后加 --enable-avformat --enable-avcodec --enable-avutil 使能我们要的三个模块。
接着--disable-everything禁止组件中个所有子模块，然后--enable-muxer=mp4 --enable-muxer=avi --enable-protocol=file --enable-encoder=mpeg4，因为我们只需要往MP4或AVI文件写H264流
下面是我最终的编译选项：
./configure --prefix=./install --enable-cross-compile --target-os=linux --cpu=cortex-a7 --arch=arm --cross-prefix=arm-hisiv300-linux- --enable-small --disable-runtime-cpudetect --disable-all --enable-avformat --enable-avcodec --enable-avutil --disable-everything --enable-muxer=mp4 --enable-muxer=avi --enable-protocol=file --enable-encoder=mpeg4 --disable-doc --disable-debug --disable-iconv --disable-armv5te --disable-armv6 --disable-armv6t2敲入上面编译选项，可得下面汇总情况：
install prefix ./install
source path .
C compiler arm-hisiv300-linux-gcc
ARCH arm (cortex-a7)
big-endian no
runtime cpu detection no
ARMv5TE enabled no
ARMv6 enabled no
ARMv6T2 enabled no
VFP enabled yes
NEON enabled yes
THUMB enabled no
debug symbols no
strip symbols yes
optimize for size yes
optimizations yes
static yes
shared no
postprocessing support no
new filter support no
network support no
threading support pthreads
safe bitstream reader yes
SDL support no
opencl enabled no
libzvbi enabled no
texi2html enabled no
perl enabled yes
pod2man enabled yes
makeinfo enabled no
External libraries:
Enabled decoders:
Enabled encoders:
h263 mpeg4
Enabled hwaccels:
Enabled parsers:
Enabled demuxers:
Enabled muxers:
avi mov mp4
Enabled protocols:
file
Enabled filters:
Enabled bsfs:
Enabled indevs:
Enabled outdevs:
License: LGPL version 2.1 or later
Creating config.mak, config.h, and doc/config.texi...可以看到，基本所有东西都是关的，就encoders只支持h263,mpeg4， muxers只支持mp4,avi,mov， protocol只支持file
最终库的大小总共在1M左右，libavcodec.a（618KB）， libavformat.a（245KB），libavutil.a（233KB）