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/sh
 export PREBUILT=/dao/work/tools/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3
 export PLATFORM=/dao/work/tools/android-ndk-r5b/platforms/android-9/arch-arm
 export 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.h
 sed -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-4.4.3
 export PLATFORM=/dao/work/tools/android-ndk-r5b/platforms/android-9/arch-arm
 export 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 := avformat
 LOCAL_SRC_FILES := libavformat.a
 LOCAL_CFLAGS :=-Ilibavformat
 LOCAL_EXPORT_C_INCLUDES := libavformat
 LOCAL_EXPORT_CFLAGS := -Ilibavformat
 LOCAL_EXPORT_LDLIBS := -llog
 include $(PREBUILT_STATIC_LIBRARY)

 include $(CLEAR_VARS)
 LOCAL_MODULE := avcodec
 LOCAL_SRC_FILES := libavcodec.a
 LOCAL_CFLAGS :=-Ilibavcodec
 LOCAL_EXPORT_C_INCLUDES := libavcodec
 LOCAL_EXPORT_CFLAGS := -Ilibavcodec
 LOCAL_EXPORT_LDLIBS := -llog
 include $(PREBUILT_STATIC_LIBRARY)

 include $(CLEAR_VARS)
 LOCAL_MODULE := avutil
 LOCAL_SRC_FILES := libavutil.a
 LOCAL_CFLAGS :=-Ilibavutil
 LOCAL_EXPORT_C_INCLUDES := libavutil
 LOCAL_EXPORT_CFLAGS := -Ilibavutil
 LOCAL_EXPORT_LDLIBS := -llog
 include $(PREBUILT_STATIC_LIBRARY)

 include $(CLEAR_VARS)
 LOCAL_MODULE := swscale
 LOCAL_SRC_FILES :=libswscale.a
 LOCAL_CFLAGS :=-Ilibavutil -Ilibswscale
 LOCAL_EXPORT_C_INCLUDES := libswscale
 LOCAL_EXPORT_CFLAGS := -Ilibswscale
 LOCAL_EXPORT_LDLIBS := -llog -lavutil
 include $(PREBUILT_STATIC_LIBRARY)

 include $(CLEAR_VARS)
 LOCAL_MODULE    := ffmpegutils
 LOCAL_SRC_FILES := native.c
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
 LOCAL_LDLIBS    := -L$(LOCAL_PATH) -lm -lz
 LOCAL_STATIC_LIBRARIES := avformat avcodec avutil swscale
 include $(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;
     }
     else
         return 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 package
     public 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;
     //size
     public 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;
     @Override
     protected 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() {

         @Override
         public void run() {
             // TODO Auto-generated method stub
             VideoBit.copyPixelsFromBuffer(Imagbuf);
             mImag.setImageBitmap(VideoBit);
         }
     };

     class StartThread extends Thread {

         @Override
         public 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);
     }

     @Override
     public 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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