android使用ffmpeg库

1.建立一个安卓工程，创建jni目录，将上一篇文章中的库和头文件拷贝到jni目录中，并创建Android.mk文件.并创建一个main.c
2.工程目录如下图



3.main.c文件内容

#include <string.h>
#include <jni.h>
#include <dlfcn.h>
#include <android/log.h>
#include "libavcodec/avcodec.h"


#define TAG "kx_ffmpeg"
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG ,__VA_ARGS__)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG ,__VA_ARGS__)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,TAG ,__VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG ,__VA_ARGS__)
#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,TAG ,__VA_ARGS__)

jint Java_com_kk_xx_ffmpeg_FFMPEGInterface_test(JNIEnv *env, jobject obj, jint codecID)
{
                AVCodec *codec = NULL;

                /*register all formats and codecs */
                av_register_all();

                codec= avcodec_find_decoder(codecID);

                if(codec != NULL)
                {
                       return 0;
                }
                else
                {
                      return -1;
                }
}

4.Android.mk内容
LOCAL_PATH := $(callmy-dir)
MY_PATH := /home/kangxian/FFMPEG/ffmpeg_android/testFFMPEG/app/jni
MY_INCLUDE_PATH := /home/kangxian/FFMPEG/ffmpeg_android/testFFMPEG/app/jni/prebuilt
define walk
$(wildcard $(1)) $(foreach e, $(wildcard $(1)/*), $(call walk, $(e)))
endef

$(warning $(MY_PATH))

include $(CLEAR_VARS)
LOCAL_MODULE := avcodec-57-prebuilt
LOCAL_SRC_FILES := $(MY_PATH)/prebuilt/libavcodec-57.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE :=avdevice-57-prebuilt
LOCAL_SRC_FILES :=$(MY_PATH)/prebuilt/libavdevice-57.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE :=avfilter-6-prebuilt
LOCAL_SRC_FILES :=$(MY_PATH)/prebuilt/libavfilter-6.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE :=avformat-57-prebuilt
LOCAL_SRC_FILES :=$(MY_PATH)/prebuilt/libavformat-57.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE :=  avutil-55-prebuilt
LOCAL_SRC_FILES :=$(MY_PATH)/prebuilt/libavutil-55.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE :=  avswresample-2-prebuilt
LOCAL_SRC_FILES :=$(MY_PATH)/prebuilt/libswresample-2.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE :=  swscale-4-prebuilt
LOCAL_SRC_FILES :=$(MY_PATH)/prebuilt/libswscale-4.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE :=kx_ffmpeg
LOCAL_SRC_FILES := $(MY_PATH)/main.c
LOCAL_C_INCLUDES := $(MY_INCLUDE_PATH)

LOCAL_LDLIBS := -llog -ljnigraphics -lz -landroid -L/home/kangxian/NDK/android-ndk-r10/platforms/android-9/arch-arm/usr/lib
LOCAL_SHARED_LIBRARIES:= avcodec-57-prebuilt avdevice-57-prebuilt avfilter-6-prebuilt avformat-57-prebuilt avutil-55-prebuilt

include $(BUILD_SHARED_LIBRARY)

5.切换到jni目录，执行ndk-build，如果没有错误，则会在libs目录下生成7个so库，如下图:



6.安卓可用的jni库就编译完成了，将7个库拷贝到安卓工程试试，如果这个jni函数返回0，证明我们编译的ffmpeg库是可用的。
7.建立和jni函数保持一致的包名和类名，如下图


8.FFMPEGInterface.java的内容

package com.kk.xx.ffmpeg;

/**
 * Created by Administrator on 2017/3/14.
 */

public class FFMPEGInterface {
    static{
        System.loadLibrary("avutil-55");
        System.loadLibrary("avcodec-57");
        System.loadLibrary("swresample-2");
        System.loadLibrary("avformat-57");
        System.loadLibrary("swscale-4");
        System.loadLibrary("avfilter-6");
        System.loadLibrary("avdevice-57");
        System.loadLibrary("kx_ffmpeg");
    }

    public static native int test(int codecID);
}