Android ffmpeg解碼

最近弄了下android ffmpeg解碼，下面把流程總結一下方便大家參考

1.ffmpeg移植

網上有一些關於ffmpeg移植的文章，試了很多次但是最後生成的libffmpeg.so就只有幾KB所以這裡換一種方式，網上也有文章說到了，其實我覺得這種方式反而要好一點，只需要生成一個庫就行了。

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

下載後，解壓進入ffmpeg-1.2.4-android目錄，裡面有一個mkconfig.sh文件，打開這個文件，你需要修改幾個地方.

mkconfig.sh內容如下:

#!/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

最開始的環境變量要設置一下:

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

這個為你的NDK的路徑，以及臨時目錄

還有一個地方需要修改:

--prefix=/dao/_install \

這個為安裝目錄，請改成你自己的。

然後執行./mkconfig.sh

應該會有一個警告，不用管。直接執行make幾分鐘左右應該就會編譯完成了，然後執行make install

在你的安裝目錄下就會生成兩個目錄include和llib到這裡 我們移植就完成了，先把這些文件放在這，後面我們需要用到。

2.jni的編寫

在你的android工程目錄下新建一個jni的目錄(其實我是在另一個工程裡新建的，前面我試了一次執行ndk-build的時候把工程裡的東西給刪除了)，把前面我們安裝的include整個目錄拷貝到jni目錄下，把lib目錄裡的所有.a文件拷貝到jni目錄下,新建Android.mk文件，內容如下:

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，這個是我們最終要調用到的文件，內容如下:

/*
 * 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 
#include 
#include 
#include 

#include 
#include 
#include 

#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;
}

最後我們只用到了兩個函數一個是init一個是decoding，這裡說明一下函數的命名方式為Java_包名_類名_函數名，com.dao.iclient是我的包名,FfmpegIF是我的類名,DecodeInit是我的函數名.如果你之前已經在系統設置了ndk的環境變量，你就可以直接在工程目錄下執行ndk-build(這裡目錄別弄錯了).最後會在工程目錄下的libs/armeabi/生成這個庫文件.

3.應用ffmpeg庫

增加FfmpegIF類,內容如下

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");
	}

}

在布局文件裡增加一個ImageView對象,我這裡是接收到網絡傳輸過來的數據後進行的解碼，我把代碼都帖上來吧，以下是我的主文件的內容:

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;
	}

}

函數說明:

mUpdateUI用於解決主進程無法刷新UI的問題

StartThread網絡通信線程主要工作是在這裡，先接收指令包，然後接收數據包,然後解碼顯示

SendCom指令包發送

putbuffer指令包生成，因為服務器是用C寫的，指令包是一個結構體所以這裡進行了這樣的處理，同時需要注意字節對齊，C語言的long類型是4個字節，Java的long類型為8個字節，這裡需要注意，我在這糾結了幾個小時。

ShorttoByteArray,InttoByteArray網絡通信格式轉換，低字節在前高字節在後

getType,getPakL,getDataL,getFrameN，指令包相關數據獲取

byte2hex將byte數組轉換成十六進制輸出，這裡是為了調試用.

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作者：hclydao
http://blog.csdn.net/hclydao
版權沒有，但是轉載請保留此段聲明

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