Android ffmpeg解码

最近弄了下android ffmpeg解码，下面把流程总结一下方便大家参考

1.ffmpeg移植

网上有一些关于ffmpeg移植的文章，试了很多次但是最后生成的libffmpeg.so就只有几KB所以这里换一种方式，网上也有文章说到了，其实我觉得这种方式反而要好一点，只需要生成一个库就行了。

我修改好的ffmpeg下载地址：http://download.csdn.net/detail/hclydao/6865961

下载后，解压进入ffmpeg-1.2.4-android目录，里面有一个mkconfig.sh文件，打开这个文件，你需要修改几个地方.

mkconfig.sh内容如下:

#!/bin/shexport PREBUILT=/dao/work/tools/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3export PLATFORM=/dao/work/tools/android-ndk-r5b/platforms/android-9/arch-armexport TMPDIR=/dao/tmp./configure \--target-os=linux \--arch=arm \--disable-ffmpeg \--disable-ffplay \--disable-ffprobe \--disable-ffserver \--disable-avdevice \--disable-avfilter \--disable-postproc \--disable-swresample \--disable-avresample \--disable-symver \--disable-debug \--disable-stripping \--disable-yasm \--disable-asm \--enable-gpl \--enable-version3 \--enable-nonfree \--disable-doc \--enable-static \--disable-shared \--enable-cross-compile \--prefix=/dao/_install \--cc=$PREBUILT/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc \--cross-prefix=$PREBUILT/prebuilt/linux-x86/bin/arm-linux-androideabi- \--nm=$PREBUILT/prebuilt/linux-x86/bin/arm-linux-androideabi-nm \--extra-cflags="-fPIC -DANDROID -I$PLATFORM/usr/include" \--extra-ldflags="-L$PLATFORM/usr/lib -nostdlib"sed -i 's/HAVE_LRINT 0/HAVE_LRINT 1/g' config.h  sed -i 's/HAVE_LRINTF 0/HAVE_LRINTF 1/g' config.h  sed -i 's/HAVE_ROUND 0/HAVE_ROUND 1/g' config.h  sed -i 's/HAVE_ROUNDF 0/HAVE_ROUNDF 1/g' config.h  sed -i 's/HAVE_TRUNC 0/HAVE_TRUNC 1/g' config.h  sed -i 's/HAVE_TRUNCF 0/HAVE_TRUNCF 1/g' config.h  sed -i 's/HAVE_CBRT 0/HAVE_CBRT 1/g' config.h  sed -i 's/HAVE_CBRTF 0/HAVE_CBRTF 1/g' config.h  sed -i 's/HAVE_ISINF 0/HAVE_ISINF 1/g' config.h  sed -i 's/HAVE_ISNAN 0/HAVE_ISNAN 1/g' config.h  sed -i 's/HAVE_SINF 0/HAVE_SINF 1/g' config.h  sed -i 's/HAVE_RINT 0/HAVE_RINT 1/g' config.hsed -i 's/#define av_restrict restrict/#define av_restrict/g' config.h

最开始的环境变量要设置一下:

export PREBUILT=/dao/work/tools/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3export PLATFORM=/dao/work/tools/android-ndk-r5b/platforms/android-9/arch-armexport TMPDIR=/dao/tmp

这个为你的NDK的路径，以及临时目录

还有一个地方需要修改:

--prefix=/dao/_install \

这个为安装目录，请改成你自己的。

然后执行./mkconfig.sh

应该会有一个警告，不用管。直接执行make几分钟左右应该就会编译完成了，然后执行make install

在你的安装目录下就会生成两个目录include和llib到这里 我们移植就完成了，先把这些文件放在这，后面我们需要用到。

2.jni的编写

在你的android工程目录下新建一个jni的目录(其实我是在另一个工程里新建的，前面我试了一次执行ndk-build的时候把工程里的东西给删除了)，把前面我们安装的include整个目录拷贝到jni目录下，把lib目录里的所有.a文件拷贝到jni目录下,新建Android.mk文件，内容如下:

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE := avformatLOCAL_SRC_FILES := libavformat.aLOCAL_CFLAGS :=-IlibavformatLOCAL_EXPORT_C_INCLUDES := libavformatLOCAL_EXPORT_CFLAGS := -IlibavformatLOCAL_EXPORT_LDLIBS := -lloginclude $(PREBUILT_STATIC_LIBRARY)include $(CLEAR_VARS)LOCAL_MODULE := avcodecLOCAL_SRC_FILES := libavcodec.aLOCAL_CFLAGS :=-IlibavcodecLOCAL_EXPORT_C_INCLUDES := libavcodecLOCAL_EXPORT_CFLAGS := -IlibavcodecLOCAL_EXPORT_LDLIBS := -lloginclude $(PREBUILT_STATIC_LIBRARY)include $(CLEAR_VARS)LOCAL_MODULE := avutilLOCAL_SRC_FILES := libavutil.aLOCAL_CFLAGS :=-IlibavutilLOCAL_EXPORT_C_INCLUDES := libavutilLOCAL_EXPORT_CFLAGS := -IlibavutilLOCAL_EXPORT_LDLIBS := -lloginclude $(PREBUILT_STATIC_LIBRARY)include $(CLEAR_VARS)LOCAL_MODULE := swscaleLOCAL_SRC_FILES :=libswscale.aLOCAL_CFLAGS :=-Ilibavutil -IlibswscaleLOCAL_EXPORT_C_INCLUDES := libswscaleLOCAL_EXPORT_CFLAGS := -IlibswscaleLOCAL_EXPORT_LDLIBS := -llog -lavutilinclude $(PREBUILT_STATIC_LIBRARY)include $(CLEAR_VARS)LOCAL_MODULE    := ffmpegutilsLOCAL_SRC_FILES := native.cLOCAL_C_INCLUDES := $(LOCAL_PATH)/includeLOCAL_LDLIBS    := -L$(LOCAL_PATH) -lm -lzLOCAL_STATIC_LIBRARIES := avformat avcodec avutil swscaleinclude $(BUILD_SHARED_LIBRARY)

新建native.c文件，这个是我们最终要调用到的文件，内容如下:

/* * Copyright 2011 - Churn Labs, LLC * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *     http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. *//* * This is mostly based off of the FFMPEG tutorial: * http://dranger.com/ffmpeg/ * With a few updates to support Android output mechanisms and to update * places where the APIs have shifted. */#include <jni.h>#include <string.h>#include <stdio.h>#include <android/log.h>#include <libavcodec/avcodec.h>#include <libavformat/avformat.h>#include <libswscale/swscale.h>#define  LOG_TAG    "FFMPEGSample"#define  LOGI(...)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)#define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)AVCodecContext * pCodecCtx = NULL;AVFrame * pFrame=NULL;AVPacket avpkt;struct SwsContext *swsctx = NULL;AVFrame * picture=NULL;JNIEXPORT jint JNICALL Java_com_dao_iclient_FfmpegIF_getffmpegv(JNIEnv * env, jclass obj){LOGI("getffmpegv");return avformat_version();}JNIEXPORT jint JNICALL Java_com_dao_iclient_FfmpegIF_DecodeInit(JNIEnv * env, jclass obj,jint width,jint height){LOGI("Decode_init");AVCodec * pCodec=NULL;avcodec_register_all();  //av_register_all();  //avcodec_init();    av_init_packet(&avpkt);pCodec=avcodec_find_decoder(CODEC_ID_H264);if(NULL!=pCodec){  pCodecCtx=avcodec_alloc_context3(pCodec);  if(avcodec_open2(pCodecCtx,pCodec,NULL)>=0){        pCodecCtx->height = height;        pCodecCtx->width = width;   pFrame=avcodec_alloc_frame();  }      return 1;} elsereturn 0;}JNIEXPORT jint JNICALL Java_com_dao_iclient_FfmpegIF_Decoding(JNIEnv * env, jclass obj,const jbyteArray pSrcData,const jint DataLen,const jbyteArray pDeData){//LOGI("Decoding");int frameFinished;int i,j;int consumed_bytes;jbyte * Buf = (jbyte*)(*env)->GetByteArrayElements(env, pSrcData, 0);jbyte * Pixel= (jbyte*)(*env)->GetByteArrayElements(env, pDeData, 0);   avpkt.data = Buf;avpkt.size = DataLen;consumed_bytes=avcodec_decode_video2(pCodecCtx,pFrame,&frameFinished,&avpkt);    //av_free_packet(&avpkt);    if(frameFinished) {picture=avcodec_alloc_frame();avpicture_fill((AVPicture *) picture, (uint8_t *)Pixel, PIX_FMT_RGB565,pCodecCtx->width,pCodecCtx->height);swsctx = sws_getContext(pCodecCtx->width,pCodecCtx->height, pCodecCtx->pix_fmt,pCodecCtx->width, pCodecCtx->height,PIX_FMT_RGB565, SWS_BICUBIC, NULL, NULL, NULL);sws_scale(swsctx,(const uint8_t* const*)pFrame->data,pFrame->linesize,0,pCodecCtx->height,picture->data,picture->linesize);}    (*env)->ReleaseByteArrayElements(env, pSrcData, Buf, 0);    (*env)->ReleaseByteArrayElements(env, pDeData, Pixel, 0);return  consumed_bytes;}JNIEXPORT jint JNICALL Java_com_dao_iclient_FfmpegIF_DecodeRelease(JNIEnv * env, jclass obj){//LOGI("Decode_release");sws_freeContext(swsctx);av_free_packet(&avpkt);av_free(pFrame);av_free(picture);avcodec_close(pCodecCtx);av_free(pCodecCtx); return 1;}

最后我们只用到了两个函数一个是init一个是decoding，这里说明一下函数的命名方式为Java_包名_类名_函数名，com.dao.iclient是我的包名,FfmpegIF是我的类名,DecodeInit是我的函数名.如果你之前已经在系统设置了ndk的环境变量，你就可以直接在工程目录下执行ndk-build(这里目录别弄错了).最后会在工程目录下的libs/armeabi/生成这个库文件.

3.应用ffmpeg库

增加FfmpegIF类,内容如下

package com.dao.iclient;public class FfmpegIF {public static short TYPE_MODE_DATA = 0;public static short TYPE_MODE_COM = 1;public static int VIDEO_COM_START = 0x00;public static int VIDEO_COM_POSE = 0x01;public static int VIDEO_COM_RUN = 0x02;public static int VIDEO_COM_ACK = 0x03;public static int VIDEO_COM_STOP = 0x04;static public native int getffmpegv();static public native int DecodeInit(int width,int height);static public native int Decoding(byte[] in,int datalen,byte[] out);static public native int DecodeRelease();static {System.loadLibrary("ffmpegutils");}}

在布局文件里增加一个ImageView对象,我这里是接收到网络传输过来的数据后进行的解码，我把代码都帖上来吧，以下是我的主文件的内容:

package com.dao.iclient;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.net.Socket;import java.nio.ByteBuffer;import java.util.Timer;import java.util.TimerTask;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.os.SystemClock;import android.view.Menu;import android.widget.ImageView;public class IcoolClient extends Activity {public Socket socket;public ByteBuffer buffer;public ByteBuffer Imagbuf;//net packagepublic static short type = 0;public static int packageLen = 0;public static int sendDeviceID = 0;public static int revceiveDeviceID = 0;public static short sendDeviceType = 0;public static int dataIndex = 0;public static int dataLen = 0;public static int frameNum = 0;public static int commType = 0;//sizepublic static int packagesize;public OutputStream outputStream=null;public InputStream inputStream=null;public int width = 0;public int height = 0;public Bitmap VideoBit;public ImageView mImag;public byte[] mout;protected static final int REFRESH = 0;private Handler mHandler;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_icool_client);mImag = (ImageView)findViewById(R.id.mimg);        packagesize = 7 * 4 + 2 * 2;        buffer = ByteBuffer.allocate(packagesize);       // int ffpmegv = FfmpegIF.getffmpegv();        //System.out.println("ffmpeg version is " + ffpmegv);        width = 640;        height = 480;        mout = new byte[width * height * 2];        Imagbuf = ByteBuffer.wrap(mout);        VideoBit = Bitmap.createBitmap(width ,height, Config.RGB_565);        //mImag.postInvalidate();        int ret = FfmpegIF.DecodeInit(width, height);        //System.out.println(" ret is " + ret);        mHandler = new Handler();        new StartThread().start();}final Runnable mUpdateUI = new Runnable() {@Overridepublic void run() {// TODO Auto-generated method stub    VideoBit.copyPixelsFromBuffer(Imagbuf);    mImag.setImageBitmap(VideoBit);}};    class StartThread extends Thread {@Overridepublic void run() {// TODO Auto-generated method stub//super.run();int datasize;try {        socket = new Socket("192.168.1.15", 9876);        //System.out.println("socket");        SendCom(FfmpegIF.VIDEO_COM_STOP);        SendCom(FfmpegIF.VIDEO_COM_START);        //new ShowBuffer().start();        inputStream = socket.getInputStream();        byte[] Rbuffer = new byte[packagesize];        while(true) {inputStream.read(Rbuffer);//byte2hex(Rbuffer);SystemClock.sleep(3);datasize = getDataL(Rbuffer);if(datasize > 0) {byte[] Data = new byte[datasize];int size;    size = inputStream.read(Data);    FfmpegIF.Decoding(Data, size, mout);    //VideoBit.copyPixelsFromBuffer(Imagbuf);    //mImag.setImageBitmap(VideoBit);    mHandler.post(mUpdateUI);    //System.out.println("read datalen is " + size);    //SystemClock.sleep(10);    SendCom(FfmpegIF.VIDEO_COM_ACK);}        }}catch (IOException e) {            e.printStackTrace();        }}    }    public void SendCom(int comtype) {    byte[] Bbuffer = new byte[packagesize];    try {    outputStream = socket.getOutputStream();    type = FfmpegIF.TYPE_MODE_COM;    packageLen = packagesize;    commType = comtype;    putbuffer();    Bbuffer = buffer.array();    outputStream.write(Bbuffer);    //System.out.println("send done");    } catch (IOException e) {            e.printStackTrace();        }     }        public void putbuffer(){    buffer.clear();        buffer.put(ShorttoByteArray(type));        buffer.put(InttoByteArray(packageLen));        buffer.put(InttoByteArray(sendDeviceID));        buffer.put(InttoByteArray(revceiveDeviceID));        buffer.put(ShorttoByteArray(sendDeviceType));        buffer.put(InttoByteArray(dataIndex));        buffer.put(InttoByteArray(dataLen));        buffer.put(InttoByteArray(frameNum));        buffer.put(InttoByteArray(commType));        //System.out.println("putbuffer done");    }        private static byte[] ShorttoByteArray(short n) {        byte[] b = new byte[2];        b[0] = (byte) (n & 0xff);        b[1] = (byte) (n >> 8 & 0xff);        return b;    }      private static byte[] InttoByteArray(int n) {        byte[] b = new byte[4];        b[0] = (byte) (n & 0xff);        b[1] = (byte) (n >> 8 & 0xff);        b[2] = (byte) (n >> 16 & 0xff);        b[3] = (byte) (n >> 24 & 0xff);        return b;    }       public short getType(byte[] tpbuffer){    short gtype = (short) ((short)tpbuffer[0] + (short)(tpbuffer[1] << 8));    //System.out.println("gtype is " + gtype);    return gtype;    }        public int getPakL(byte[] pkbuffer){    int gPackageLen = ((int)(pkbuffer[2]) & 0xff) | ((int)(pkbuffer[3] & 0xff) << 8) | ((int)(pkbuffer[4] & 0xff) << 16) | ((int)(pkbuffer[5] & 0xff) << 24);    //System.out.println("gPackageLen is " + gPackageLen);    return gPackageLen;    }        public int getDataL(byte[] getbuffer){    int gDataLen = (((int)(getbuffer[20] & 0xff)) | ((int)(getbuffer[21] & 0xff) << 8) | ((int)(getbuffer[22] & 0xff) << 16) | ((int)(getbuffer[23] & 0xff) << 24));    //System.out.println("gDataLen is " + gDataLen);    return gDataLen;    }        public int getFrameN(byte[] getbuffer){    int getFrameN = (int)(((int)(getbuffer[24])) + ((int)(getbuffer[25]) << 8) + ((int)(getbuffer[26]) << 16) + ((int)(getbuffer[27]) << 24));    //System.out.println("getFrameN is " + getFrameN);    return getFrameN;    }        private void byte2hex(byte [] buffer) {          String h = "";          for(int i = 0; i < buffer.length; i++){              String temp = Integer.toHexString(buffer[i] & 0xFF);            if(temp.length() == 1){                temp = "0" + temp;              }              h = h + " "+ temp;          }         // System.out.println(h);    }@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.icool_client, menu);return true;}}

函数说明:

mUpdateUI用于解决主进程无法刷新UI的问题

StartThread网络通信线程主要工作是在这里，先接收指令包，然后接收数据包,然后解码显示

SendCom指令包发送

putbuffer指令包生成，因为服务器是用C写的，指令包是一个结构体所以这里进行了这样的处理，同时需要注意字节对齐，C语言的long类型是4个字节，Java的long类型为8个字节，这里需要注意，我在这纠结了几个小时。

ShorttoByteArray,InttoByteArray网络通信格式转换，低字节在前高字节在后

getType,getPakL,getDataL,getFrameN，指令包相关数据获取

byte2hex将byte数组转换成十六进制输出，这里是为了调试用.

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作者：hclydao
http://blog.csdn.net/hclydao
版权没有，但是转载请保留此段声明

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