NDK下编译FFMPEG

用NDK编译FFmpeg

8 月前　 416次访问

作者： s980601 来源： eoe开发者社区

关键词： NDK 编译 FFmpeg

导读：Android内置的编解码器实在太少，于是我们需要FFmpeg。Android提供了NDK，为我们使用FFmpeg这种C语言代码提供了方便。

首先创建一个标准的Android项目vPlayer

1 android create project -n vPlayer -t 8 -p vPlayer -k me.abitno.vplayer -a PlayerView

然后在vPlayer目录里

1 mkdir jni && cd jni
2 wget http://ffmpeg.org/releases/ffmpeg-0.6.tar.bz2
3 tar xf ffmpeg-0.6.tar.bz2 && mv ffmpeg-0.6 ffmpeg && cd ffmpeg

在ffmpeg下新建一个config.sh，内容如下，注意把PREBUILT和PLATFORM设置正确。另外里面有些参数你也可以自行调整，我主要是为了配置一个播放器而这样设置的。

01 #!/bin/bash
02
03 PREBUILT=/home/abitno/Android/android-ndk-r4/build/prebuilt/linux-x86/arm-eabi-4.4.0
04 PLATFORM=/home/abitno/Android/android-ndk-r4/build/platforms/android-8/arch-arm
05
06 ./configure --target-os=linux \
07         --arch=arm \
08         --enable-version3 \
09         --enable-gpl \
10         --enable-nonfree \
11         --disable-stripping \
12         --disable-ffmpeg \
13         --disable-ffplay \
14         --disable-ffserver \
15         --disable-ffprobe \
16         --disable-encoders \
17         --disable-muxers \
18         --disable-devices \
19         --disable-protocols \
20         --enable-protocol=file \
21         --enable-avfilter \
22         --disable-network \
23         --disable-mpegaudio-hp \
24         --disable-avdevice \
25         --enable-cross-compile \
26         --cc=$PREBUILT/bin/arm-eabi-gcc \
27         --cross-prefix=$PREBUILT/bin/arm-eabi- \
28         --nm=$PREBUILT/bin/arm-eabi-nm \
29         --extra-cflags="-fPIC -DANDROID" \
30         --disable-asm \
31         --enable-neon \
32         --enable-armv5te \
33         --extra-ldflags="-Wl,-T,$PREBUILT/arm-eabi/lib/ldscripts/armelf.x -Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib $PREBUILT/lib/gcc/arm-eabi/4.4.0/crtbegin.o $PREBUILT/lib/gcc/arm-eabi/4.4.0/crtend.o -lc -lm -ldl"

运行config.sh开始configure

1 chmod +x config.sh
2 ./config.sh

configure完成后，编辑刚刚生成的config.h，找到这句

1 #define restrict restrict

Android的GCC不支持restrict关键字，于是修改成下面这样

1 #define restrict

编辑libavutil/libm.h，把其中的static方法都删除。分别修改libavcodec、libavfilter、libavformat、libavutil、libpostproc和libswscale下的Makefile，把下面两句删除

1 include $(SUBDIR)../subdir.mak
2 include $(SUBDIR)../config.mak

在ffmpeg下添加一个文件av.mk，内容如下

01 # LOCAL_PATH is one of libavutil, libavcodec, libavformat, or libswscale
02
03 #include $(LOCAL_PATH)/../config-$(TARGET_ARCH).mak
04 include $(LOCAL_PATH)/../config.mak
05
06 OBJS :=
07 OBJS-yes :=
08 MMX-OBJS-yes :=
09 include $(LOCAL_PATH)/Makefile
10
11 # collect objects
12 OBJS-$(HAVE_MMX) += $(MMX-OBJS-yes)
13 OBJS += $(OBJS-yes)
14
15 FFNAME := lib$(NAME)
16 FFLIBS := $(foreach,NAME,$(FFLIBS),lib$(NAME))
17 FFCFLAGS  = -DHAVE_AV_CONFIG_H -Wno-sign-compare -Wno-switch -Wno-pointer-sign
18 FFCFLAGS += -DTARGET_CONFIG=\"config-$(TARGET_ARCH).h\"
19
20 ALL_S_FILES := $(wildcard $(LOCAL_PATH)/$(TARGET_ARCH)/*.S)
21 ALL_S_FILES := $(addprefix $(TARGET_ARCH)/, $(notdir $(ALL_S_FILES)))
22
23 ifneq ($(ALL_S_FILES),)
24 ALL_S_OBJS := $(patsubst %.S,%.o,$(ALL_S_FILES))
25 C_OBJS := $(filter-out $(ALL_S_OBJS),$(OBJS))
26 S_OBJS := $(filter $(ALL_S_OBJS),$(OBJS))
27 else
28 C_OBJS := $(OBJS)
29 S_OBJS :=
30 endif
31
32 C_FILES := $(patsubst %.o,%.c,$(C_OBJS))
33 S_FILES := $(patsubst %.o,%.S,$(S_OBJS))
34
35 FFFILES := $(sort $(S_FILES)) $(sort $(C_FILES))

接下来要添加一系列的Android.mk，在jni根目录下的内容如下

1 include $(all-subdir-makefiles)

在ffmpeg目录下，Android.mk

1 LOCAL_PATH := $(call my-dir)
2 include $(CLEAR_VARS)
3 LOCAL_STATIC_LIBRARIES := libavformat libavcodec libavutil libpostproc libswscale
4 LOCAL_MODULE := ffmpeg
5 include $(BUILD_SHARED_LIBRARY)
6 include $(call all-makefiles-under,$(LOCAL_PATH))

libavformat/Android.mk

01 LOCAL_PATH := $(call my-dir)
02 include $(CLEAR_VARS)
03 include $(LOCAL_PATH)/../av.mk
04 LOCAL_SRC_FILES := $(FFFILES)
05 LOCAL_C_INCLUDES :=                \
06         $(LOCAL_PATH)                \
07         $(LOCAL_PATH)/..
08 LOCAL_CFLAGS += $(FFCFLAGS)
09 LOCAL_CFLAGS += -include "string.h" -Dipv6mr_interface=ipv6mr_ifindex
10 LOCAL_LDLIBS := -lz
11 LOCAL_STATIC_LIBRARIES := $(FFLIBS)
12 LOCAL_MODULE := $(FFNAME)
13 include $(BUILD_STATIC_LIBRARY)

libavcodec/Android.mk

01 LOCAL_PATH := $(call my-dir)
02 include $(CLEAR_VARS)
03 include $(LOCAL_PATH)/../av.mk
04 LOCAL_SRC_FILES := $(FFFILES)
05 LOCAL_C_INCLUDES :=                \
06         $(LOCAL_PATH)                \
07         $(LOCAL_PATH)/..
08 LOCAL_CFLAGS += $(FFCFLAGS)
09 LOCAL_LDLIBS := -lz
10 LOCAL_STATIC_LIBRARIES := $(FFLIBS)
11 LOCAL_MODULE := $(FFNAME)
12 include $(BUILD_STATIC_LIBRARY)

libavfilter、libavutil、libpostproc和libswscale下的Android.mk内容如下

01 LOCAL_PATH := $(call my-dir)
02 include $(CLEAR_VARS)
03 include $(LOCAL_PATH)/../av.mk
04 LOCAL_SRC_FILES := $(FFFILES)
05 LOCAL_C_INCLUDES :=                \
06         $(LOCAL_PATH)                \
07         $(LOCAL_PATH)/..
08 LOCAL_CFLAGS += $(FFCFLAGS)
09 LOCAL_STATIC_LIBRARIES := $(FFLIBS)
10 LOCAL_MODULE := $(FFNAME)
11 include $(BUILD_STATIC_LIBRARY)

最外层的jni/Android.mk和jni/ffmpeg/Android.mk只是随便这样写的，你应该根据自己的需求改写