Amdroid直播开发之旅(5)：详解ffmpeg编译与在Android平台上的移植

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jiangdongguo@jiangdg:~$ export NDK=/home/jiangdongguo/ffmpeg/android-ndk-r14b
jiangdongguo@jiangdg:~$ export TMPDIR=/home/jiangdongguo/ffmpeg/ffmpegTmpDir

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root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2# vim configure_arm.sh

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// 修改ffmpeg源码下configure文件
root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2# vim configure

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SLIBNAME_WITH_VERSION='$(SLIBNAME).$(LIBVERSION)'	
SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'		
LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'
将上面的内容修改如下：
SLIBNAME_WITH_VERSION='$(SLIBNAME).$(LIBVERSION)'
SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'

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// 赋予configure_arm.sh执行权限
root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2# chmod u+x configure_arm.sh
// 执行脚本文件
root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2# ./configure_arm.sh

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root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2#make clean
root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2#make 
root@jiangdg:/home/jiangdongguo/ffmpeg/ffmpeg-3.3.2#make install

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/** 处理视频native方法工具类
 * 
 * @author Created by jianddongguo on 2017年6月26日下午11:14:27
 * @blogs http://blog.csdn.net/andrexpert
 */
public class VideoFixUtils {
	
	/** 获得指定视频的角度
	 * @param videoPath 视频路径
	 * @return 拍摄角度值
	 */
	public native static int getVideoAngle(String videoPath);
	
	static {
		// 加载自定义动态库
		System.loadLibrary("FFMPEG4Android");
		// 加载ffmpeg相关动态库
		System.loadLibrary("avcodec-57");
		System.loadLibrary("avdevice-57");
		System.loadLibrary("avfilter-6");
		System.loadLibrary("avformat-57");
		System.loadLibrary("avutil-55");
		System.loadLibrary("swscale-4");
		System.loadLibrary("swresample-2");
	}	
}

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/** 处理视频c实现
 * 
 * @author Created by jianddongguo on 2017年6月26日下午11:14:27
 * @blogs http://blog.csdn.net/andrexpert
 */
#include <jni.h>
#include <stdlib.h>
#include "com_jiangdg_ffmepg4android_VideoFixUtils.h"
#include "ffmpeg.h"


JNIEXPORT jint JNICALL Java_com_jiangdg_ffmepg4androidk_VideoFixUtils_getVideoAngle
  (JNIEnv *env, jclass jcls, jstring j_videoPath){
	const char *c_videoPath = (*env)->GetStringUTFChars(env,j_videoPath,NULL);
	//1. 注册所有组件
	av_register_all();
	//2. 打开视频、获取视频信息，
	// 	其中，fmtCtx为封装格式上下文
	AVFormatContext *fmtCtx = avformat_alloc_context();
	avformat_open_input(&fmtCtx,c_videoPath,NULL,NULL);
	//3. 获取视频流的索引位置
	int i;
	int v_stream_idx = -1;
	for(i=0 ; i<fmtCtx->nb_streams ; i++){
		if(fmtCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){
			v_stream_idx = i;
			break;
		}
	}
	// 4. 获取旋转角度，元数据
	AVDictionaryEntry *tag = NULL;
	tag = av_dict_get(fmtCtx->streams[v_stream_idx]->metadata,"rotate",tag,NULL);
	int angle = -1;
	if(tag != NULL){
		// 将char *强制转换为into类型
		angle = atoi(tag->value);
	}
	// 5.释放封装格式上下文
	avformat_free_context(fmtCtx);
	(*env)->ReleaseStringUTFChars(env,j_videoPath,c_videoPath);
	return angle;
}

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LOCAL_PATH := $(call my-dir)
#ffmpeg prebuilt lib
include $(CLEAR_VARS)
LOCAL_MODULE    := avcodec_prebuilt
LOCAL_SRC_FILES := libavcodec-57.so
include $(PREBUILT_SHARED_LIBRARY)


include $(CLEAR_VARS)
LOCAL_MODULE    := avdevice_prebuilt
LOCAL_SRC_FILES := libavdevice-57.so
include $(PREBUILT_SHARED_LIBRARY)


include $(CLEAR_VARS)
LOCAL_MODULE    := avfilter_prebuilt
LOCAL_SRC_FILES := libavfilter-6.so
include $(PREBUILT_SHARED_LIBRARY)


include $(CLEAR_VARS)
LOCAL_MODULE    := avformat_prebuilt
LOCAL_SRC_FILES := libavformat-57.so
include $(PREBUILT_SHARED_LIBRARY)


include $(CLEAR_VARS)
LOCAL_MODULE    := avutil_prebuilt
LOCAL_SRC_FILES := libavutil-55.so
include $(PREBUILT_SHARED_LIBRARY)


include $(CLEAR_VARS)
LOCAL_MODULE    := swresample_prebuilt
LOCAL_SRC_FILES := libswresample-2.so
include $(PREBUILT_SHARED_LIBRARY)


include $(CLEAR_VARS)
LOCAL_MODULE    := swscale_prebuilt
LOCAL_SRC_FILES := libswscale-4.so
include $(PREBUILT_SHARED_LIBRARY)


#myapp lib
include $(CLEAR_VARS)
LOCAL_MODULE    := FFMPEG4Android
LOCAL_SRC_FILES := FFMPEG4Android.c
LOCAL_C_INCLUDES +=$(LOCAL_PATH)/include
LOCAL_LDLIBS := -llog
LOCAL_SHARED_LIBRARIES := avcodec_prebuilt avdevice_prebuilt avfilter_prebuilt avformat_prebuilt avutil_prebuilt swresample_prebuilt swscale_prebuilt
include $(BUILD_SHARED_LIBRARY)

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#指定so支持的平台
APP_ABI := armeabi

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public class MainActivity extends Activity {
	private TextView mTvDegreeInfo;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		mTvDegreeInfo = (TextView) findViewById(R.id.tv_video_degree);
	}


	public void onRotateClick(View v) {
		String rootPath = Environment.getExternalStorageDirectory().getAbsolutePath();
		File file = new File(rootPath + File.separator + "20170627_145524.mp4");
		if (!file.exists()) {
			return;
		}
		mTvDegreeInfo.setText(
				"读取到20170627_145524.mp4的旋转角度：n rotate = " 
		+ VideoFixUtils.getVideoAngle(file.getAbsolutePath()) + "度");
	}