ffmpeg超詳細綜合教程

mediatv 2016-07-11

展開全文

本文的示例將實現(xiàn)：讀取安卓手機攝像頭數(shù)據(jù)并使用H.264編碼格式實時編碼保存為flv文件。示例包含了

1、編譯適用于安卓平臺的ffmpeg庫

2、在java中通過JNI使用ffmpeg

3、讀取安卓攝像頭數(shù)據(jù)并在后臺線程中使用ffmpeg進行編碼的基本流程

具有較強的綜合性。

編譯適用于安卓平臺的ffmpeg庫

平時我們編譯ffmpeg類庫都是在x86平臺下，而安卓手機屬于arm平臺，所以要先通過交叉編譯的方法在x86平臺下編譯出可以在arm平臺下使用的 ffmpeg類庫。Google就為我們提供了一套可以再Linux下完成該任務的交叉編譯工具鏈——NDK，下載時可以看到google同時提供了 ndk的windows版和linux版，前者可以在windows下通過cygwin（可以理解為一個在windows下模擬linux的工具）使用。我這里使用的是Android-ndk-r10e，在cygwin下使用。ndk的下載安裝基本是傻瓜式的，但要注意linux系統(tǒng)對x86和x64是分的很清楚的，不像windows那么隨性，此外還需要提醒的是，在下載安裝cygwin時，只需要選擇binutils
, gcc , gcc-mingw , gdb , make這幾個組件。安裝完成后，在cygwin安裝目錄下點擊cygwin.bat打開命令窗口，輸入make -version驗證是否安裝成功。

做好以上的準備工作之后就可以正式開始ffmpeg源碼的編譯了。
首先需要修改configure文件，確保類庫版本號不會出現(xiàn)在.so后綴名的后面，否則安卓平臺無法識別這樣的類庫
找到下面幾句

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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)'

修改為

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SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'

之后進行常規(guī)的configure配置，make， make install步驟即可，下面給出一個常規(guī)的腳本示例

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make clean
export NDK=xxxx/android-ndk-r10e
export PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt
export PLATFORM=$NDK/platforms/android-8/arch-arm
export PREFIX=../android_ffmpeglib
./configure --target-os=linux --prefix=$PREFIX \
--enable-cross-compile \
--enable-runtime-cpudetect \
--disable-asm \
--arch=arm \
--cc=$PREBUILT/windows/bin/arm-linux-androideabi-gcc \
--cross-prefix=$PREBUILT/windows/bin/arm-linux-androideabi- \
--disable-stripping \
--nm=$PREBUILT/windows/bin/arm-linux-androideabi-nm \
--sysroot=$PLATFORM \
--enable-gpl --enable-shared --disable-static --enable-small \
--disable-ffprobe --disable-ffplay --disable-ffmpeg --disable-ffserver --disable-debug \
--extra-cflags="-fPIC -DANDROID -D__thumb__ -mthumb -Wfatal-errors -Wno-deprecated -mfloat-abi=softfp -marm -march=armv7-a"
make
make install

成功編譯后，可以看到如下類庫

在java中通過JNI使用ffmpeg

JNI 即java本地接口，java native interface，它是一個協(xié)議, 該協(xié)議用來溝通Java代碼和外部的本地C/C++代碼, 通過該協(xié)議 Java代碼可以調(diào)用外部的本地代碼, 外部的C/C++ 代碼可以調(diào)用Java代碼。簡單來說，就是將一個C語言的方法映射到Java的某個方法上;

JNI中的一些概念 :

-- native : Java語言中修飾本地方法的修飾符, 被該修飾符修飾的方法沒有方法體;

-- Native方法 : 在Java語言中被native關(guān)鍵字修飾的方法是Native方法;

-- JNI層 : Java聲明Native方法的部分;

-- JNI函數(shù) : JNIEnv提供的函數(shù), 這些函數(shù)在jni.h中進行定義;

-- JNI方法 : Native方法對應的JNI層實現(xiàn)的 C/C++方法, 即在jni目錄中實現(xiàn)的那些C語言代碼;

具體流程可以參照ndk的sample目錄下的hellojni項目，總結(jié)起來有如下幾個步驟
1、創(chuàng)建常規(guī)Android項目
2、聲明Native方法，形如public native String stringFromJNI();
3、創(chuàng)建c文件
在工程根目錄下創(chuàng)建 jni 目錄, 然后創(chuàng)建一個c語言源文件, 在文件中引入 include <jni.h>。c語言方法聲明形如

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jstring
Java_com_example_hellojni_HelloJni_stringFromJNI( JNIEnv* env,
jobject thiz )

jstring 是 Java語言中的String類型, 方法名格式為 : Java_完整包名類名_方法名();

-- JNIEnv參數(shù) : 代表的是Java環(huán)境, 通過這個環(huán)境可以調(diào)用Java里面的方法;

-- jobject參數(shù) : 調(diào)用C語言方法的對象, thiz對象表示當前的對象, 即調(diào)用JNI方法所在的類;

4、編寫Android.mk文件
就好比常用的makefile，形如

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LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := hello-jni
LOCAL_SRC_FILES := hello-jni.c
include $(BUILD_SHARED_LIBRARY)

-- LOCAL_PATH : 代表mk文件所在的目錄;

-- include $(CLEAR_VARS) : 編譯工具函數(shù), 通過該函數(shù)可以進行一些初始化操作;

-- LOCAL_MODULE : 編譯后的 .so 后綴文件叫什么名字;

-- LOCAL_SRC_FILES: 指定編譯的源文件名稱;

-- include $(BUILD_SHARED_LIBRARY) : 告訴編譯器需要生成動態(tài)庫;

5、NDK編譯生成動態(tài)庫
利用上面寫好的.mk文件，進入 cygdrive 找到windows目錄下對應的文件, 編譯完成之后, 會自動生成so文件并放在libs目錄下, 之后就可以在Java中調(diào)用C語言方法了;

6、java中加載動態(tài)庫
在Java類中的靜態(tài)代碼塊中使用System.LoadLibrary()方法加載編譯好的 .so 動態(tài)庫，形如

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static {
System.loadLibrary("hello-jni");
}

需要說明的是，調(diào)試JNI程序非常麻煩，無法進入c文件中進行單步調(diào)試，只能通過輸出一些信息然后利用logcat進行調(diào)試，所以也可以先在vs里面把c文件的內(nèi)容跑一遍簡單驗證一下。

參照上面的基本流程，具體到利用ffmpeg實現(xiàn)安卓攝像頭數(shù)據(jù)的編碼
第一步：我們聲明如下四個Native方法

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//JNI
//初始化，讀取待編碼數(shù)據(jù)的寬和高
public native int initial(int width,int height);
//讀取yuv數(shù)據(jù)進行編碼
public native int encode(byte[] yuvimage);
//清空緩存的幀
public native int flush();
//清理
public native int close();

第二步：對應的c文件內(nèi)容如下，基本就是一個將yuv數(shù)據(jù)編碼為H.264的flv文件的流程，唯一需要注意的就是安卓攝像頭拍攝數(shù)據(jù)的像素格式為NV21，需要轉(zhuǎn)換為YUV420P才能進行編碼

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/**
* 基于FFmpeg安卓攝像頭編碼
* FFmpeg Android Camera Encoder
*
* 張暉 Hui Zhang
* zhanghuicuc@gmail.com
* 中國傳媒大學/數(shù)字電視技術(shù)
* Communication University of China / Digital TV Technology
*
*
*/
#include <stdio.h>
#include <time.h>
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavutil/log.h"
#ifdef ANDROID
#include <jni.h>
#include <android/log.h>
#define LOGE(format, ...) __android_log_print(ANDROID_LOG_ERROR, "(>_<)", format, ##__VA_ARGS__)
#define LOGI(format, ...) __android_log_print(ANDROID_LOG_INFO, "(=_=)", format, ##__VA_ARGS__)
#else
#define LOGE(format, ...) printf("(>_<) " format "\n", ##__VA_ARGS__)
#define LOGI(format, ...) printf("(^_^) " format "\n", ##__VA_ARGS__)
#endif
AVFormatContext *ofmt_ctx;
AVStream* video_st;
AVCodecContext* pCodecCtx;
AVCodec* pCodec;
AVPacket enc_pkt;
AVFrame *pFrameYUV;
int framecnt = 0;
int yuv_width;
int yuv_height;
int y_length;
int uv_length;
int64_t start_time;
//Output FFmpeg's av_log()
void custom_log(void *ptr, int level, const char* fmt, va_list vl){
FILE *fp=fopen("/storage/emulated/0/av_log.txt","a+");
if(fp){
vfprintf(fp,fmt,vl);
fflush(fp);
fclose(fp);
}
}
JNIEXPORT jint JNICALL Java_com_zhanghui_test_MainActivity_initial
(JNIEnv *env, jobject obj,jint width,jint height)
{
const char* out_path = "/sdcard/zhanghui/testffmpeg.flv";
yuv_width=width;
yuv_height=height;
y_length=width*height;
uv_length=width*height/4;
//FFmpeg av_log() callback
av_log_set_callback(custom_log);
av_register_all();
//output initialize
avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", out_path);
//output encoder initialize
pCodec = avcodec_find_encoder(AV_CODEC_ID_H264);
if (!pCodec){
LOGE("Can not find encoder!\n");
return -1;
}
pCodecCtx = avcodec_alloc_context3(pCodec);
pCodecCtx->pix_fmt = PIX_FMT_YUV420P;
pCodecCtx->width = width;
pCodecCtx->height = height;
pCodecCtx->time_base.num = 1;
pCodecCtx->time_base.den = 30;
pCodecCtx->bit_rate = 800000;
pCodecCtx->gop_size = 300;
/* Some formats want stream headers to be separate. */
if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
pCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;
//H264 codec param
//pCodecCtx->me_range = 16;
//pCodecCtx->max_qdiff = 4;
//pCodecCtx->qcompress = 0.6;
pCodecCtx->qmin = 10;
pCodecCtx->qmax = 51;
//Optional Param
pCodecCtx->max_b_frames = 3;
// Set H264 preset and tune
AVDictionary *param = 0;
av_dict_set(?m, "preset", "ultrafast", 0);
av_dict_set(?m, "tune", "zerolatency", 0);
if (avcodec_open2(pCodecCtx, pCodec, ?m) < 0){
LOGE("Failed to open encoder!\n");
return -1;
}
//Add a new stream to output,should be called by the user before avformat_write_header() for muxing
video_st = avformat_new_stream(ofmt_ctx, pCodec);
if (video_st == NULL){
return -1;
}
video_st->time_base.num = 1;
video_st->time_base.den = 30;
video_st->codec = pCodecCtx;
//Open output URL,set before avformat_write_header() for muxing
if (avio_open(&ofmt_ctx->pb, out_path, AVIO_FLAG_READ_WRITE) < 0){
LOGE("Failed to open output file!\n");
return -1;
}
//Write File Header
avformat_write_header(ofmt_ctx, NULL);
start_time = av_gettime();
return 0;
}
JNIEXPORT jint JNICALL Java_com_zhanghui_test_MainActivity_encode
(JNIEnv *env, jobject obj, jbyteArray yuv)
{
int ret;
int enc_got_frame=0;
int i=0;
pFrameYUV = avcodec_alloc_frame();
uint8_t *out_buffer = (uint8_t *)av_malloc(avpicture_get_size(PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));
avpicture_fill((AVPicture *)pFrameYUV, out_buffer, PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);
//安卓攝像頭數(shù)據(jù)為NV21格式，此處將其轉(zhuǎn)換為YUV420P格式
jbyte* in= (jbyte*)(*env)->GetByteArrayElements(env,yuv,0);
memcpy(pFrameYUV->data[0],in,y_length);
for(i=0;i<uv_length;i++)
{
*(pFrameYUV->data[2]+i)=*(in+y_length+i*2);
*(pFrameYUV->data[1]+i)=*(in+y_length+i*2+1);
}
pFrameYUV->format = AV_PIX_FMT_YUV420P;
pFrameYUV->width = yuv_width;
pFrameYUV->height = yuv_height;
enc_pkt.data = NULL;
enc_pkt.size = 0;
av_init_packet(&enc_pkt);
ret = avcodec_encode_video2(pCodecCtx, &enc_pkt, pFrameYUV, &enc_got_frame);
av_frame_free(&pFrameYUV);
if (enc_got_frame == 1){
LOGI("Succeed to encode frame: %5d\tsize:%5d\n", framecnt, enc_pkt.size);
framecnt++;
enc_pkt.stream_index = video_st->index;
//Write PTS
AVRational time_base = ofmt_ctx->streams[0]->time_base;//{ 1, 1000 };
AVRational r_framerate1 = {60, 2 };//{ 50, 2 };
AVRational time_base_q = { 1, AV_TIME_BASE };
//Duration between 2 frames (us)
int64_t calc_duration = (double)(AV_TIME_BASE)*(1 / av_q2d(r_framerate1)); //內(nèi)部時間戳
//Parameters
//enc_pkt.pts = (double)(framecnt*calc_duration)*(double)(av_q2d(time_base_q)) / (double)(av_q2d(time_base));
enc_pkt.pts = av_rescale_q(framecnt*calc_duration, time_base_q, time_base);
enc_pkt.dts = enc_pkt.pts;
enc_pkt.duration = av_rescale_q(calc_duration, time_base_q, time_base); //(double)(calc_duration)*(double)(av_q2d(time_base_q)) / (double)(av_q2d(time_base));
enc_pkt.pos = -1;
//Delay
int64_t pts_time = av_rescale_q(enc_pkt.dts, time_base, time_base_q);
int64_t now_time = av_gettime() - start_time;
if (pts_time > now_time)
av_usleep(pts_time - now_time);
ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt);
av_free_packet(&enc_pkt);
}
return 0;
}
JNIEXPORT jint JNICALL Java_com_zhanghui_test_MainActivity_flush
(JNIEnv *env, jobject obj)
{
int ret;
int got_frame;
AVPacket enc_pkt;
if (!(ofmt_ctx->streams[0]->codec->codec->capabilities &
CODEC_CAP_DELAY))
return 0;
while (1) {
enc_pkt.data = NULL;
enc_pkt.size = 0;
av_init_packet(&enc_pkt);
ret = avcodec_encode_video2(ofmt_ctx->streams[0]->codec, &enc_pkt,
NULL, &got_frame);
if (ret < 0)
break;
if (!got_frame){
ret = 0;
break;
}
LOGI("Flush Encoder: Succeed to encode 1 frame!\tsize:%5d\n", enc_pkt.size);
//Write PTS
AVRational time_base = ofmt_ctx->streams[0]->time_base;//{ 1, 1000 };
AVRational r_framerate1 = { 60, 2 };
AVRational time_base_q = { 1, AV_TIME_BASE };
//Duration between 2 frames (us)
int64_t calc_duration = (double)(AV_TIME_BASE)*(1 / av_q2d(r_framerate1)); //內(nèi)部時間戳
//Parameters
enc_pkt.pts = av_rescale_q(framecnt*calc_duration, time_base_q, time_base);
enc_pkt.dts = enc_pkt.pts;
enc_pkt.duration = av_rescale_q(calc_duration, time_base_q, time_base);
//轉(zhuǎn)換PTS/DTS（Convert PTS/DTS）
enc_pkt.pos = -1;
framecnt++;
ofmt_ctx->duration = enc_pkt.duration * framecnt;
/* mux encoded frame */
ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt);
if (ret < 0)
break;
}
//Write file trailer
av_write_trailer(ofmt_ctx);
return 0;
}
JNIEXPORT jint JNICALL Java_com_zhanghui_test_MainActivity_close
(JNIEnv *env, jobject obj)
{
if (video_st)
avcodec_close(video_st->codec);
avio_close(ofmt_ctx->pb);
avformat_free_context(ofmt_ctx);
return 0;
}

第三步：編寫Android.mk如下，這里要在jni目錄下放入ffmpeg的頭文件，就跟平時的調(diào)用方法一樣

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LOCAL_PATH := $(call my-dir)
# FFmpeg library
include $(CLEAR_VARS)
LOCAL_MODULE := avcodec
LOCAL_SRC_FILES := libavcodec-56.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := avdevice
LOCAL_SRC_FILES := libavdevice-56.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := avfilter
LOCAL_SRC_FILES := libavfilter-5.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := avformat
LOCAL_SRC_FILES := libavformat-56.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := avutil
LOCAL_SRC_FILES := libavutil-54.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := postproc
LOCAL_SRC_FILES := libpostproc-53.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := swresample
LOCAL_SRC_FILES := libswresample-1.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := swscale
LOCAL_SRC_FILES := libswscale-3.so
include $(PREBUILT_SHARED_LIBRARY)
# Program
include $(CLEAR_VARS)
LOCAL_MODULE := encode
LOCAL_SRC_FILES :=encode.c
LOCAL_C_INCLUDES += $(LOCAL_PATH)/include
LOCAL_LDLIBS := -llog -lz
LOCAL_SHARED_LIBRARIES := avcodec avdevice avfilter avformat avutil postproc swresample swscale
include $(BUILD_SHARED_LIBRARY)

第四步：使用cygwin切換到當前項目的jni目錄下，輸入ndk-build進行編譯即可，如下

此時就可以在當前項目的libs目錄下看到ffmpeg所有的類庫以及我們自己的類庫，我這里是libencode.so，如下

第五步：在java中加載動態(tài)庫

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static{
System.loadLibrary("avutil-54");
System.loadLibrary("swresample-1");
System.loadLibrary("avcodec-56");
System.loadLibrary("avformat-56");
System.loadLibrary("swscale-3");
System.loadLibrary("postproc-53");
System.loadLibrary("avfilter-5");
System.loadLibrary("avdevice-56");
System.loadLibrary("encode");
}

至此，就可以在java中調(diào)用我們聲明的四個方法了。

java部分獲取攝像頭數(shù)據(jù)并編碼的流程

簡單來說，就是利用Camera的PreviewCallback獲得攝像頭數(shù)據(jù)，在通過AsyncTask開啟后臺線程將攝像頭數(shù)據(jù)進行編碼。這里為了避免編碼過程占用過多的硬件資源，將編碼視頻寬和高設(shè)置為了640和480,。
這里有兩個坑，一是onPreviewFrame方法的arg0參數(shù)就是YUV數(shù)據(jù)了，不要再轉(zhuǎn)換為YuvImage對象了，否則會在頭部加上一些多余的信息，導致編碼錯誤，二是用于清空緩存幀的flush方法不能在oncreate主線程中調(diào)用，否則會導致程序閃退，目前還不清楚原因，所以這里連同 close()方法一起放到了onPause方法中進行調(diào)用，在安卓開發(fā)方面我還是新手，希望有了解這個問題怎么解決的朋友多多指教。

[java] view plain copy

package com.zhanghui.test; import java.io.IOException; import android.annotation.TargetApi; import android.app.Activity; import android.content.pm.PackageManager; import android.hardware.Camera; import android.os.AsyncTask; import android.os.Build; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.widget.Button; import android.widget.Toast; @SuppressWarnings("deprecation") public class MainActivity extends Activity { private static final String TAG= "MainActivity"; private Button mTakeButton; private Camera mCamera; private SurfaceView mSurfaceView; private SurfaceHolder mSurfaceHolder; private boolean isRecording = false; private class StreamTask extends AsyncTask<Void, Void, Void>{ private byte[] mData; // 構(gòu)造函數(shù) StreamTask(byte[] data) { this.mData = data; } @Override protected Void doInBackground(Void... params) { // TODO Auto-generated method stub if(mData!=null){ Log.i(TAG, "fps: " + mCamera.getParameters().getPreviewFrameRate()); encode(mData); } return null; } } private StreamTask mStreamTask; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final Camera.PreviewCallback mPreviewCallbacx=new Camera.PreviewCallback() { @Override public void onPreviewFrame(byte[] arg0, Camera arg1) { // TODO Auto-generated method stub if(null != mStreamTask){ switch(mStreamTask.getStatus()){ case RUNNING: return; case PENDING: mStreamTask.cancel(false); break; } } mStreamTask = new StreamTask(arg0); mStreamTask.execute((Void)null); } }; mTakeButton=(Button)findViewById(R.id.take_button); PackageManager pm=this.getPackageManager(); boolean hasCamera=pm.hasSystemFeature(PackageManager.FEATURE_CAMERA) || pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT) || Build.VERSION.SDK_INT<Build.VERSION_CODES.GINGERBREAD; if(!hasCamera) mTakeButton.setEnabled(false); mTakeButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { // TODO Auto-generated method stub if(mCamera!=null) { if (isRecording) { mTakeButton.setText("Start"); mCamera.setPreviewCallback(null); Toast.makeText(MainActivity.this, "encode done", Toast.LENGTH_SHORT).show(); isRecording = false; }else { mTakeButton.setText("Stop"); initial(mCamera.getParameters().getPreviewSize().width,mCamera.getParameters().getPreviewSize().height); mCamera.setPreviewCallback(mPreviewCallbacx); isRecording = true; } } } }); mSurfaceView=(SurfaceView)findViewById(R.id.surfaceView1); SurfaceHolder holder=mSurfaceView.getHolder(); holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); holder.addCallback(new SurfaceHolder.Callback() { @Override public void surfaceDestroyed(SurfaceHolder arg0) { // TODO Auto-generated method stub if(mCamera!=null) { mCamera.stopPreview(); mSurfaceView = null; mSurfaceHolder = null; } } @Override public void surfaceCreated(SurfaceHolder arg0) { // TODO Auto-generated method stub try{ if(mCamera!=null){ mCamera.setPreviewDisplay(arg0); mSurfaceHolder=arg0; } }catch(IOException exception){ Log.e(TAG, "Error setting up preview display", exception); } } @Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { // TODO Auto-generated method stub if(mCamera==null) return; Camera.Parameters parameters=mCamera.getParameters(); parameters.setPreviewSize(640,480); parameters.setPictureSize(640,480); mCamera.setParameters(parameters); try{ mCamera.startPreview(); mSurfaceHolder=arg0; }catch(Exception e){ Log.e(TAG, "could not start preview", e); mCamera.release(); mCamera=null; } } }); } @TargetApi(9) @Override protected void onResume(){ super.onResume(); if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.GINGERBREAD){ mCamera=Camera.open(0); }else { mCamera=Camera.open(); } } @Override protected void onPause(){ super.onPause(); flush(); close(); if(mCamera!=null){ mCamera.release(); mCamera=null; } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } //JNI public native int initial(int width,int height); public native int encode(byte[] yuvimage); public native int flush(); public native int close(); static{
System.loadLibrary("avutil-54");
System.loadLibrary("swresample-1");
System.loadLibrary("avcodec-56");
System.loadLibrary("avformat-56");
System.loadLibrary("swscale-3");
System.loadLibrary("postproc-53");
System.loadLibrary("avfilter-5");
System.loadLibrary("avdevice-56");
System.loadLibrary("encode");
} }