ffmpeg使用NDK r9编译

国内网站找了许多都没有成功。以下在mac和ubuntu上译编成功

Thisisaupdatedpostforapreviouspost,wherewebuilt
ffmpeg0.8withAndroidNDKr5andr6.Thispostwillgiveinstructionsofhowtobuildffmpeg2.0.1withAndroidNDKr9.

0.DownloadAndroidNDK

ThelatestversionofAndroidNDKcanbedownloadedatAndroid
NDKwebsite.Atthetimeofwriting,thenewestversionisNDKr9.Notethatthewebsiteprovidesbothcurrentandlegacytoolchains.Weonlyneedthecurrenttoolchaintocompileffmpeg.

AfterdownloadNDK,simplydecompressthearchive.Notethatwe’lluse$NDKtorepresenttherootpathofthedecompressedNDK.

1.Downloadffmpegsourcecode

FFMPEGsourcecodecanbedownloadedfromtheffmpeg
website.Thelateststablereleaseis2.0.1.Downloadthesourcecodeanddecompressitto$NDK/sourcesfolder.We’lldiscussaboutthereasonfordoingthislater.

2.Updateconfigurefile

Openffmpeg-2.0.1/configurefilewithatexteditor,andlocatethefollowinglines.

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)'

Thiscauseffmpegsharedlibrariestobecompiledtolibavcodec.so.<version>(e.g.libavcodec.so.55),whichisnotcompatiblewithAndroidbuildsystem.Thereforewe’llneedtoreplacetheabovelineswiththefollowinglines.

SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'

LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'

SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'

SLIB_INSTALL_LINKS='$(SLIBNAME)'

3.Buildffmpeg

Copythefollowingtexttoatexteditorandsaveitasbuild_android.sh.

#!/bin/bash

NDK=$HOME/Desktop/adt/android-ndk-r9

SYSROOT=$NDK/platforms/android-9/arch-arm/

TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64

functionbuild_one

{

./configure\

--prefix=$PREFIX\

--enable-shared\

--disable-static\

--disable-doc\

--disable-ffmpeg\

--disable-ffplay\

--disable-ffprobe\

--disable-ffserver\

--disable-avdevice\

--disable-doc\

--disable-symver\

--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi-\

--target-os=linux\

--arch=arm\

--enable-cross-compile\

--sysroot=$SYSROOT\

--extra-cflags="-Os-fpic$ADDI_CFLAGS"\

--extra-ldflags="$ADDI_LDFLAGS"\

$ADDITIONAL_CONFIGURE_FLAG

makeclean

make

makeinstall

}

CPU=arm

PREFIX=$(pwd)/android/$CPU

ADDI_CFLAGS="-marm"

build_one

Wedisabledstaticlibraryandenabledsharedlibrary.NotethatthebuildscriptisnotoptimizedforaparticularCPU.Oneshouldrefertoffmpegdocumentationfordetailedinformationaboutavailableconfigureoptions.

Oncethefileissaved,makesurethescriptisexecutablebythecommandbelow,

sudochmod+xbuild_android.sh

Thenexecutethescriptbythecommand,

./build_android.sh

4.BuildOutput

Thebuildcantakeawhiletofinishdependingonyourcomputerspeed.Onceit’sdone,youshouldbeabletofindafolder$NDK/sources/ffmpeg-2.0.1/android,whichcontainsarm/libandarm/includefolders.

Thearm/libfoldercontainsthesharedlibraries,whilearm/includefoldercontainstheheaderfilesforlibavcodec,libavformat,libavfilter,libavutil,libswscaleetc.

Notethatthearm/libfoldercontainsboththelibraryfiles(e.g.:libavcodec-55.so)andsymboliclinks(e.g.:libavcodec.so)tothem.Wecanremovethesymboliclinkstoavoidconfusion.

5.MakeffmpegLibrariesavailableforYourProjects

Nowwe’vecompiledtheffmpeglibrariesandreadytousethem.AndroidNDKallowsustoreuseacompiledmodulethroughtheimport-modulebuildcommand.

Thereasonwebuiltourffmpegsourcecodeunder$NDK/sourcesfolderisthatNDKbuildsystemwillsearchfordirectoriesunderthispathforexternalmodulesautomatically.Todeclaretheffmpeglibrariesasreusablemodules,we’llneedtoaddafilenamed
$NDK/sources/ffmpeg-2.0.1/android/arm/Android.mkwiththefollowingcontent,

LOCAL_PATH:=$(callmy-dir)

include$(CLEAR_VARS)

LOCAL_MODULE:=libavcodec

LOCAL_SRC_FILES:=lib/libavcodec-55.so

LOCAL_EXPORT_C_INCLUDES:=$(LOCAL_PATH)/include

include$(PREBUILT_SHARED_LIBRARY)

include$(CLEAR_VARS)

LOCAL_MODULE:=libavformat

LOCAL_SRC_FILES:=lib/libavformat-55.so

LOCAL_EXPORT_C_INCLUDES:=$(LOCAL_PATH)/include

include$(PREBUILT_SHARED_LIBRARY)

include$(CLEAR_VARS)

LOCAL_MODULE:=libswscale

LOCAL_SRC_FILES:=lib/libswscale-2.so

LOCAL_EXPORT_C_INCLUDES:=$(LOCAL_PATH)/include

include$(PREBUILT_SHARED_LIBRARY)

include$(CLEAR_VARS)

LOCAL_MODULE:=libavutil

LOCAL_SRC_FILES:=lib/libavutil-52.so

LOCAL_EXPORT_C_INCLUDES:=$(LOCAL_PATH)/include

include$(PREBUILT_SHARED_LIBRARY)

include$(CLEAR_VARS)

LOCAL_MODULE:=libavfilter

LOCAL_SRC_FILES:=lib/libavfilter-3.so

LOCAL_EXPORT_C_INCLUDES:=$(LOCAL_PATH)/include

include$(PREBUILT_SHARED_LIBRARY)

include$(CLEAR_VARS)

LOCAL_MODULE:=libwsresample

LOCAL_SRC_FILES:=lib/libswresample-0.so

LOCAL_EXPORT_C_INCLUDES:=$(LOCAL_PATH)/include

include$(PREBUILT_SHARED_LIBRARY)

BelowisanexampleofhowwecanusethelibrariesinaAndroidproject’sjni/Android.mkfile,

LOCAL_PATH:=$(callmy-dir)

include$(CLEAR_VARS)

LOCAL_MODULE:=tutorial03

LOCAL_SRC_FILES:=tutorial03.c

LOCAL_LDLIBS:=-llog-ljnigraphics-lz-landroid

LOCAL_SHARED_LIBRARIES:=libavformatlibavcodeclibswscalelibavutil

include$(BUILD_SHARED_LIBRARY)

$(callimport-module,ffmpeg-2.0.1/android/arm)

Notethatwecalledimport-modulewiththerelativepathto$NDK/sourcesforthebuildsystemtolocatethereusableffmpeglibraries.

ForrealexamplestohowtousetheffmpeglibrariesinAndroidapp,pleaserefertomygithubrepoofandroid-ffmpeg-tutorial.