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

NDK下编译FFMPEG

用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。

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