FFmpeg 2.8.4 移植到android平台(一)

移植环境：

VirtualBox 下的Ubuntu 14.04 LTS （64位）
adt-bundle-linux-x86_64-20140321
android-ndk-r9d-linux-x86_64

所需资源：

FFmpeg 2.8.4

准备工作：

1.配置android sdk环境变量（注意：在linux环境下安装了android sdk，也已经配置好了环境变量，但是执行adb的时候出现如下错误：
    mtl@xxx-Lenovo:/usr/xxx/android-sdk/platform-tools$ adb-bash: /usr/xxx/android-sdk/platform-tools/adb: 没有那个文件或目录 ；
    出现这个问题的原因是机子是64位的，但是android sdk又是32位的，所以需要执行如下命令：
    sudo apt-get install lib32bz2-1.0
    sudo apt-get install lib32ncurses5 lib32stdc++6

2.配置ndk环境变量

移植步骤：

1.创建目录 ~/lplayer/jni （为了省事，这里我执行了chmod 777 jni）；

2.解压FFmpeg 2.8.4源码，并重名为ffmepg，然后放入~/lplayer/jni

3.创建相应NDK配置文件：

    （1）~/lplayer/jni/Android.mk

        include $(all-subdir-makefiles)

    （2）~/lplayer/jni/ffmpeg/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        LOCAL_WHOLE_STATIC_LIBRARIES := libavformat libavcodec libavutil libpostproc libswscale

        LOCAL_MODULE := ffmpeg

        include $(BUILD_SHARED_LIBRARY)

        include $(call all-makefiles-under,$(LOCAL_PATH))

    （3）~/lplayer/jni/ffmpeg/av.mk

        # LOCAL_PATH is one of libavutil, libavcodec, libavformat, or libswscale

        #include $(LOCAL_PATH)/../config-$(TARGET_ARCH).mak

        include $(LOCAL_PATH)/../config.mak

        OBJS :=

        OBJS-yes :=

        MMX-OBJS-yes :=

        include $(LOCAL_PATH)/Makefile

        # collect objects

        OBJS-$(HAVE_MMX) += $(MMX-OBJS-yes)

        OBJS += $(OBJS-yes)

        FFNAME := lib$(NAME)

        FFLIBS := $(foreach,NAME,$(FFLIBS),lib$(NAME))

        FFCFLAGS  = -DHAVE_AV_CONFIG_H -Wno-sign-compare -Wno-switch -Wno-pointer-sign

        FFCFLAGS += -DTARGET_CONFIG=\"config-$(TARGET_ARCH).h\"

        ALL_S_FILES := $(wildcard $(LOCAL_PATH)/$(TARGET_ARCH)/*.S)

        ALL_S_FILES := $(addprefix $(TARGET_ARCH)/, $(notdir $(ALL_S_FILES)))

        ifneq ($(ALL_S_FILES),)

        ALL_S_OBJS := $(patsubst %.S,%.o,$(ALL_S_FILES))

        C_OBJS := $(filter-out $(ALL_S_OBJS),$(OBJS))

        S_OBJS := $(filter $(ALL_S_OBJS),$(OBJS))

        else

        C_OBJS := $(OBJS)

        S_OBJS :=

        endif

        C_FILES := $(patsubst %.o,%.c,$(C_OBJS))

        S_FILES := $(patsubst %.o,%.S,$(S_OBJS))

        FFFILES := $(sort $(S_FILES)) $(sort $(C_FILES))

    （4）~/lplayer/jni/ffmpeg/libavcodec/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        include $(LOCAL_PATH)/../av.mk

        LOCAL_SRC_FILES := $(FFFILES)

        LOCAL_C_INCLUDES :=        \

            $(LOCAL_PATH)        \

            $(LOCAL_PATH)/..

        LOCAL_CFLAGS += $(FFCFLAGS)

        LOCAL_LDLIBS := -lz

        LOCAL_STATIC_LIBRARIES := $(FFLIBS)

        LOCAL_MODULE := $(FFNAME)

        include $(BUILD_STATIC_LIBRARY)

    （5）~/lplayer/jni/ffmpeg/libavformat/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        include $(LOCAL_PATH)/../av.mk

        LOCAL_SRC_FILES := $(FFFILES)

        LOCAL_C_INCLUDES :=        \

            $(LOCAL_PATH)        \

            $(LOCAL_PATH)/..

        LOCAL_CFLAGS += $(FFCFLAGS)

        LOCAL_CFLAGS += -include "string.h" -Dipv6mr_interface=ipv6mr_ifindex

        LOCAL_LDLIBS := -lz

        LOCAL_STATIC_LIBRARIES := $(FFLIBS)

        LOCAL_MODULE := $(FFNAME)

        include $(BUILD_STATIC_LIBRARY)

    （6）~/lplayer/jni/ffmpeg/libavfilter/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        include $(LOCAL_PATH)/../av.mk

        LOCAL_SRC_FILES := $(FFFILES)

        LOCAL_C_INCLUDES :=        \

            $(LOCAL_PATH)        \

            $(LOCAL_PATH)/..

        LOCAL_CFLAGS += $(FFCFLAGS)

        LOCAL_STATIC_LIBRARIES := $(FFLIBS)

        LOCAL_MODULE := $(FFNAME)

        include $(BUILD_STATIC_LIBRARY)

    （7）~/lplayer/jni/ffmpeg/libavutil/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        include $(LOCAL_PATH)/../av.mk

        LOCAL_SRC_FILES := $(FFFILES)

        LOCAL_C_INCLUDES :=        \

            $(LOCAL_PATH)        \

            $(LOCAL_PATH)/..

        LOCAL_CFLAGS += $(FFCFLAGS)

        LOCAL_STATIC_LIBRARIES := $(FFLIBS)

        LOCAL_MODULE := $(FFNAME)

        include $(BUILD_STATIC_LIBRARY)

    （8）~/lplayer/jni/ffmpeg/libpostproc/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        include $(LOCAL_PATH)/../av.mk

        LOCAL_SRC_FILES := $(FFFILES)

        LOCAL_C_INCLUDES :=        \

            $(LOCAL_PATH)        \

            $(LOCAL_PATH)/..

        LOCAL_CFLAGS += $(FFCFLAGS)

        LOCAL_STATIC_LIBRARIES := $(FFLIBS)

        LOCAL_MODULE := $(FFNAME)

        include $(BUILD_STATIC_LIBRARY)

    （9）~/lplayer/jni/ffmpeg/libswscale/Android.mk

        LOCAL_PATH := $(call my-dir)

        include $(CLEAR_VARS)

        include $(LOCAL_PATH)/../av.mk

        LOCAL_SRC_FILES := $(FFFILES)

        LOCAL_C_INCLUDES :=        \

            $(LOCAL_PATH)        \

            $(LOCAL_PATH)/..

        LOCAL_CFLAGS += $(FFCFLAGS)

        LOCAL_STATIC_LIBRARIES := $(FFLIBS)

        LOCAL_MODULE := $(FFNAME)

        include $(BUILD_STATIC_LIBRARY)

4.编写ffmepg配置脚本：~/lpayer/jni/ffmpeg/config.sh 注意其中的NDK路径，请修改成你系统中对应的安装路径

    #!/bin/bash

    PREBUILT=/home/lfn/software/android/android-ndk-r9d/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64

    PLATFORM=/home/lfn/software/android/android-ndk-r9d/platforms/android-9/arch-arm
./configure --target-os=linux \

         --arch=arm \          --enable-version3 \          --enable-gpl \          --enable-nonfree \          --disable-stripping \          --disable-ffmpeg \          --disable-ffplay \          --disable-ffserver \          --disable-ffprobe \          --disable-encoders \          --disable-muxers \          --disable-devices \          --disable-protocols \          --enable-protocol=file \          --enable-avfilter \          --disable-network \          --disable-avdevice \          --disable-asm \          --enable-cross-compile \          --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \          --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \          --strip=$PREBUILT/bin/arm-linux-androideabi-strip \          --extra-cflags="-fPIC -DANDROID" \          --extra-ldflags="-Wl,-T,$PREBUILT/arm-linux-androideabi/lib/ldscripts/armelf_linux_eabi.x -Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib $PREBUILT/lib/gcc/arm-linux-androideabi/4.6/crtbegin.o $PREBUILT/lib/gcc/arm-linux-androideabi/4.6/crtend.o -lc -lm -ldl"

5.运行配置文件

    chmod 755 config.sh
    ./config.sh

这时会在~/lplayer/jni/ffmpeg目录下生成三个文件: config.h，config.mak，config.log。我们需要修改config.h文件，将其中的

    #define av_restrict restrict

修改成

    #define restrict

6.修改ffmpeg代码，以便在NDK中编译通过: 修改~/lplayer/jni/ffmpeg/libavutil/libm.h文件，
  将其中的所有static方法都注释掉(为了省事我直接删掉的); 
  修改ffmpeg源码目录中的
  libavcodev，libavfilter，libavformat，
  libavutil，libpostproc，libswscale中的Makefile，
  将Makefile中的开头：include $(SUBDIR)../config.mak都注释掉。

7.开始编译
（1）、进入目录：~/lplayer
（2）、运行命令：ndk-build

8.收工
假如你没有错误，恭喜你，在目录~/lplayer/libs/armeabi下会有libffmpeg.so文件，
这就是ffmpeg的库文件，可以直接拿来在通过JNI或者P/Invoke技术，使用了！

运行截图

1.运行配置文件（即上述步骤5）
![这里写图片描述](http://img.blog.csdn.net/20160115164013654)
虽然有警告，没有发现对结果有影响

2.开始编译（即上述步骤7）
![这里写图片描述](http://img.blog.csdn.net/20160115163824025)

后记

运气比较好，一次成功。没成功的童鞋，自行百度，谷歌出错原因^_^