流媒体程序开发之：H264解码器移植到OPhone

1. 移植目标
将H.264解码器移植到OPhone操作系统之上（NDK+C），并写一个测试程序（OPhoneSDK+Java）测试解码库是否正常运行，下面是解码时的截图：

OPhone的模拟器和Mobile的模拟器一样是模拟ARM指令的，不像Symbian模拟器一样执行的是本地代码，所以在模拟器上模拟出来的效率会比 真实手机上的效率要低，之前这款解码器已经优化到在nokia 6600（相当低端的一款手机，CPU主频才120Hz）上做到在线播放。

2. 面向人群
本文面向有一定的手机应用开发经验（例如：S60/Mobile/MTK）和有一定的跨手机平台移植经验的人员，帮助她们了解一个企业的核心库（C/C++）是怎么移植到OPhone之上的。

3. 假定前提
1)熟悉Java/C/C++语言；
2)熟悉Java的JNI技术；
3)有一定的跨手机平台移植经验；
4)有一套可供移植的源代码库，这里以H.264解码库为例，为了保护我们的知识版权，这里只能够公开头文件：

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1. #ifndef__H264DECODE_H__
2. #define__H264DECODE_H__
4. #ifdefined(__SYMBIAN32__)//S602rd/3rd/UIQ
5. #include<e32base.h>
6. #include<libc"stdio.h>
7. #include<libc"stdlib.h>
8. #include<libc"string.h>
9. #else//Windows/Mobile/MTK/OPhone
10. #include<stdio.h>
11. #include<stdlib.h>
12. #include<string.h>
13. #endif
15. classH264Decode
16. {
17. public:
18. /***************************************************************************/
19. /*构造解码器*/
20. /*@returnH264Decode解码器实例*/
21. /***************************************************************************/
22. staticH264Decode*H264DecodeConstruct();
23. /***************************************************************************/
24. /*解码一帧*/
25. /*@pInBuffer指向H264的视频流*/
26. /*@iInSizeH264视频流的大小*/
27. /*@pOutBuffer解码后的视频视频*/
28. /*@iOutSize解码后的视频大小*/
29. /*@return已解码的H264视频流的尺寸*/
30. /***************************************************************************/
31. intDecodeOneFrame(unsignedchar*pInBuffer,unsignedintiInSize,unsignedchar*pOutBuffer,unsignedint&iOutSize);
32. ~H264Decode();
33. };
34. #endif//__H264DECODE_H__

#ifndef __H264DECODE_H__
#define __H264DECODE_H__
#if defined(__SYMBIAN32__)	//S602rd/3rd/UIQ
#include <e32base.h>
#include <libc"stdio.h>
#include <libc"stdlib.h>
#include <libc"string.h>
#else						//Windows/Mobile/MTK/OPhone
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#endif
class H264Decode
{
public:
/***************************************************************************/
/* 构造解码器														*/
/* @return H264Decode解码器实例										*/
/***************************************************************************/
static H264Decode *H264DecodeConstruct();
/***************************************************************************/
/* 解码一帧														*/
/* @pInBuffer	指向H264的视频流										*/
/* @iInSize	H264视频流的大小										*/
/* @pOutBuffer	解码后的视频视频										*/
/* @iOutSize	解码后的视频大小										*/
/* @return		已解码的H264视频流的尺寸								*/
/***************************************************************************/
int DecodeOneFrame(unsigned char *pInBuffer,unsigned int iInSize,unsigned char *pOutBuffer,unsigned int &iOutSize);
~H264Decode();
};
#endif  // __H264DECODE_H__

你不用熟悉OPhone平台，一切从零开始，因为在此之前，我也不熟悉。

4. 开发环境(请参考: http://www.ophonesdn.com/documentation/)

5. 移植过程

5.1移植流程

5.2 封装Java接口

在“假定前提”中提到了要移植的函数，接下来会编写这些 函数的Java Native Interface。

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1. packageophone.streaming.video.h264;
3. importjava.nio.ByteBuffer;
5. publicclassH264decode{
7. //H264解码库指针，因为Java没有指针一说，所以这里用一个32位的数来存放指针的值
8. privatelongH264decode=0;
10. static{
11. System.loadLibrary("H264Decode");
12. }
14. publicH264decode(){
15. this.H264decode=Initialize();
16. }
18. publicvoidCleanup(){
19. Destroy(H264decode);
20. }
22. publicintDecodeOneFrame(ByteBufferpInBuffer,ByteBufferpOutBuffer){
23. returnDecodeOneFrame(H264decode,pInBuffer,pOutBuffer);
24. }
26. privatenativestaticintDecodeOneFrame(longH264decode,ByteBufferpInBuffer,ByteBufferpOutBuffer);
27. privatenativestaticlongInitialize();
28. privatenativestaticvoidDestroy(longH264decode);
29. }

package ophone.streaming.video.h264;
import java.nio.ByteBuffer;
public class H264decode {
//H264解码库指针，因为Java没有指针一说，所以这里用一个32位的数来存放指针的值
private long H264decode = 0;
static{
System.loadLibrary("H264Decode");
}
public H264decode() {
this.H264decode = Initialize();
}
public void Cleanup() {
Destroy(H264decode);
}
public int DecodeOneFrame(ByteBuffer pInBuffer,ByteBuffer pOutBuffer) {
return DecodeOneFrame(H264decode, pInBuffer, pOutBuffer);
}
private native static int DecodeOneFrame(long H264decode,ByteBuffer pInBuffer,ByteBuffer pOutBuffer);
private native static long Initialize();
private native static void Destroy(long H264decode);
}

这块没什么好说的，就是按照H264解码库的函数，封装的一层接口，如果你熟悉Java JNI，会发现原来是这么类似。这里插入一句：我一直认为技术都是相通的，底层的技术就那么几种，学懂了，其它技术都是一通百通。

5.3 使用C实现本地方法

5.3.1生成头文件

使用javah命令生成JNI头文件，这里需要注意是class路径不是源代码的路径，并且要加上包名：

这里生成了一个ophone_streaming_video_h264_H264decode.h，我们打开来看看：

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1. #include<jni.h>
3. #ifndef_Included_ophone_streaming_video_h264_H264decode
4. #define_Included_ophone_streaming_video_h264_H264decode
5. #ifdef__cplusplus
6. extern"C"{
7. #endif
9. JNIEXPORTjintJNICALLJava_ophone_streaming_video_h264_H264decode_DecodeOneFrame
10. (JNIEnv*,jclass,jlong,jobject,jobject);
12. JNIEXPORTjlongJNICALLJava_ophone_streaming_video_h264_H264decode_Initialize
13. (JNIEnv*,jclass);
15. JNIEXPORTvoidJNICALLJava_ophone_streaming_video_h264_H264decode_Destroy
16. (JNIEnv*,jclass,jlong);
18. #ifdef__cplusplus
19. }
20. #endif
21. #endif

#include <jni.h>
#ifndef _Included_ophone_streaming_video_h264_H264decode
#define _Included_ophone_streaming_video_h264_H264decode
#ifdef __cplusplus
extern "C" {
#endif
JNIEXPORT jint JNICALL Java_ophone_streaming_video_h264_H264decode_DecodeOneFrame
(JNIEnv *, jclass, jlong, jobject, jobject);
JNIEXPORT jlong JNICALL Java_ophone_streaming_video_h264_H264decode_Initialize
(JNIEnv *, jclass);
JNIEXPORT void JNICALL Java_ophone_streaming_video_h264_H264decode_Destroy
(JNIEnv *, jclass, jlong);
#ifdef __cplusplus
}
#endif
#endif

5.3.2实现本地方法

之前已经生成了JNI头文件，接下来只需要实现这个头文件的几个导出函数，这里以H264解码器的实现为例：

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1. #include"ophone_streaming_video_h264_H264decode.h"
2. #include"H264Decode.h"
4. JNIEXPORTjintJNICALLJava_ophone_streaming_video_h264_H264decode_DecodeOneFrame
5. (JNIEnv*env,jclassobj,jlongdecode,jobjectpInBuffer,jobjectpOutBuffer){
7. H264Decode*pDecode=(H264Decode*)decode;
8. unsignedchar*In=NULL;unsignedchar*Out=NULL;
9. unsignedintInPosition=0;unsignedintInRemaining=0;unsignedintInSize=0;
10. unsignedintOutSize=0;
11. jintDecodeSize=-1;
13. jbyte*InJbyte=0;
14. jbyte*OutJbyte=0;
16. jbyteArrayInByteArrary=0;
17. jbyteArrayOutByteArrary=0;
19. //获取Input/OutByteBuffer相关属性
20. {
21. //Input
22. {
23. jclassByteBufferClass=env->GetObjectClass(pInBuffer);
24. jmethodIDPositionMethodId=env->GetMethodID(ByteBufferClass,"position","()I");
25. jmethodIDRemainingMethodId=env->GetMethodID(ByteBufferClass,"remaining","()I");
26. jmethodIDArraryMethodId=env->GetMethodID(ByteBufferClass,"array","()[B");
28. InPosition=env->CallIntMethod(pInBuffer,PositionMethodId);
29. InRemaining=env->CallIntMethod(pInBuffer,RemainingMethodId);
30. InSize=InPosition+InRemaining;
32. InByteArrary=(jbyteArray)env->CallObjectMethod(pInBuffer,ArraryMethodId);
34. InJbyte=env->GetByteArrayElements(InByteArrary,0);
36. In=(unsignedchar*)InJbyte+InPosition;
37. }
39. //Output
40. {
41. jclassByteBufferClass=env->GetObjectClass(pOutBuffer);
42. jmethodIDArraryMethodId=env->GetMethodID(ByteBufferClass,"array","()[B");
43. jmethodIDClearMethodId=env->GetMethodID(ByteBufferClass,"clear","()Ljava/nio/Buffer;");
45. //清理输出缓存区
46. env->CallObjectMethod(pOutBuffer,ClearMethodId);
48. OutByteArrary=(jbyteArray)env->CallObjectMethod(pOutBuffer,ArraryMethodId);
49. OutJbyte=env->GetByteArrayElements(OutByteArrary,0);
51. Out=(unsignedchar*)OutJbyte;
52. }
53. }
55. //解码
56. DecodeSize=pDecode->DecodeOneFrame(In,InRemaining,Out,OutSize);
58. //设置Input/OutputByteBuffer相关属性
59. {
60. //Input
61. {
62. jclassByteBufferClass=env->GetObjectClass(pInBuffer);
63. jmethodIDSetPositionMethodId=env->GetMethodID(ByteBufferClass,"position","(I)Ljava/nio/Buffer;");
65. //设置输入缓冲区偏移
66. env->CallObjectMethod(pInBuffer,SetPositionMethodId,InPosition+DecodeSize);
67. }
69. //Output
70. {
71. jclassByteBufferClass=env->GetObjectClass(pOutBuffer);
72. jmethodIDSetPositionMethodId=env->GetMethodID(ByteBufferClass,"position","(I)Ljava/nio/Buffer;");
74. //设置输出缓冲区偏移
75. env->CallObjectMethod(pOutBuffer,SetPositionMethodId,OutSize);
76. }
77. }
79. //清理
80. env->ReleaseByteArrayElements(InByteArrary,InJbyte,0);
81. env->ReleaseByteArrayElements(OutByteArrary,OutJbyte,0);
83. returnDecodeSize;
84. }
86. JNIEXPORTjlongJNICALLJava_ophone_streaming_video_h264_H264decode_Initialize
87. (JNIEnv*env,jclassobj){
89. H264Decode*pDecode=H264Decode::H264DecodeConstruct();
90. return(jlong)pDecode;
91. }
93. JNIEXPORTvoidJNICALLJava_ophone_streaming_video_h264_H264decode_Destroy
94. (JNIEnv*env,jclassobj,jlongdecode){
96. H264Decode*pDecode=(H264Decode*)decode;
97. if(pDecode)
98. {
99. deletepDecode;
100. pDecode=NULL;
101. }
102. }

#include "ophone_streaming_video_h264_H264decode.h"
#include "H264Decode.h"
JNIEXPORT jint JNICALL Java_ophone_streaming_video_h264_H264decode_DecodeOneFrame
(JNIEnv * env, jclass obj, jlong decode, jobject pInBuffer, jobject pOutBuffer) {
H264Decode *pDecode = (H264Decode *)decode;
unsigned char *In = NULL;unsigned char *Out = NULL;
unsigned int InPosition = 0;unsigned int InRemaining = 0;unsigned int InSize = 0;
unsigned int OutSize = 0;
jint DecodeSize = -1;
jbyte *InJbyte = 0;
jbyte *OutJbyte = 0;
jbyteArray InByteArrary = 0;
jbyteArray OutByteArrary = 0;
//获取Input/Out ByteBuffer相关属性
{
//Input
{
jclass ByteBufferClass = env->GetObjectClass(pInBuffer);
jmethodID PositionMethodId = env->GetMethodID(ByteBufferClass,"position","()I");
jmethodID RemainingMethodId = env->GetMethodID(ByteBufferClass,"remaining","()I");
jmethodID ArraryMethodId = env->GetMethodID(ByteBufferClass,"array","()[B");
InPosition = env->CallIntMethod(pInBuffer,PositionMethodId);
InRemaining = env->CallIntMethod(pInBuffer,RemainingMethodId);
InSize = InPosition + InRemaining;
InByteArrary = (jbyteArray)env->CallObjectMethod(pInBuffer,ArraryMethodId);
InJbyte = env->GetByteArrayElements(InByteArrary,0);
In = (unsigned char*)InJbyte + InPosition;
}
//Output
{
jclass ByteBufferClass = env->GetObjectClass(pOutBuffer);
jmethodID ArraryMethodId = env->GetMethodID(ByteBufferClass,"array","()[B");
jmethodID ClearMethodId = env->GetMethodID(ByteBufferClass,"clear","()Ljava/nio/Buffer;");
//清理输出缓存区
env->CallObjectMethod(pOutBuffer,ClearMethodId);
OutByteArrary = (jbyteArray)env->CallObjectMethod(pOutBuffer,ArraryMethodId);
OutJbyte = env->GetByteArrayElements(OutByteArrary,0);
Out = (unsigned char*)OutJbyte;
}
}
//解码
DecodeSize = pDecode->DecodeOneFrame(In,InRemaining,Out,OutSize);
//设置Input/Output ByteBuffer相关属性
{
//Input
{
jclass ByteBufferClass = env->GetObjectClass(pInBuffer);
jmethodID SetPositionMethodId = env->GetMethodID(ByteBufferClass,"position","(I)Ljava/nio/Buffer;");
//设置输入缓冲区偏移
env->CallObjectMethod(pInBuffer,SetPositionMethodId,InPosition + DecodeSize);
}
//Output
{
jclass ByteBufferClass = env->GetObjectClass(pOutBuffer);
jmethodID SetPositionMethodId = env->GetMethodID(ByteBufferClass,"position","(I)Ljava/nio/Buffer;");
//设置输出缓冲区偏移
env->CallObjectMethod(pOutBuffer,SetPositionMethodId,OutSize);
}
}
//清理
env->ReleaseByteArrayElements(InByteArrary,InJbyte,0);
env->ReleaseByteArrayElements(OutByteArrary,OutJbyte,0);
return DecodeSize;
}
JNIEXPORT jlong JNICALL Java_ophone_streaming_video_h264_H264decode_Initialize
(JNIEnv * env, jclass obj) {
H264Decode *pDecode = H264Decode::H264DecodeConstruct();
return (jlong)pDecode;
}
JNIEXPORT void JNICALL Java_ophone_streaming_video_h264_H264decode_Destroy
(JNIEnv * env, jclass obj, jlong decode) {
H264Decode *pDecode = (H264Decode *)decode;
if (pDecode)
{
delete pDecode;
pDecode = NULL;
}
}

5.3.3编译本地方法

接下来，只需要把用C实现的本地方法编译为动态链接库，如果之前你用于移植的那个库曾经移植到Symbian上过，那么编译会相当简单，因为NDK的编译器和Symbian的编译器一样，都是采用GCC做交叉编译器。

首先，需要在$NDK"apps目录下，创建一个项目目录，这里创建了一个H264Decode目录，在H264Decode目录中，创建一个Android.mk文件：

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1. APP_PROJECT_PATH:=$(callmy-dir)
2. APP_MODULES:=H264Decode

APP_PROJECT_PATH := $(call my-dir)
APP_MODULES      := H264Decode

接下来，需要在$NDK"source目录下，创建源代码目录（这里的目录名要和上面创建的项目目录文件名相同），这里创建一个H264Decode目录，然后把之前生成的JNI头文件和你实现的本地方法相关头文件和源代码，都拷贝到 这个目录下面。

然后，我们编辑Android.mk文件：

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1. LOCAL_PATH:=$(callmy-dir)
2. include$(CLEAR_VARS)
3. LOCAL_MODULE:=H264Decode
4. LOCAL_SRC_FILES:=common.ccabac.cutils.cgolomb.cmpegvideo.cmem.cimgconvert.ch264decode.cpph264.cdsputil.cophone_streaming_video_h264_H264decode.cpp
5. include$(BUILD_SHARED_LIBRARY)

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE    := H264Decode
LOCAL_SRC_FILES := common.c cabac.c utils.c golomb.c mpegvideo.c mem.c imgconvert.c h264decode.cpp h264.c dsputil.c ophone_streaming_video_h264_H264decode.cpp
include $(BUILD_SHARED_LIBRARY)

关于Android.mk文件中，各个字段的解释，可以参考$NDK"doc下的《OPHONE-MK.TXT》和《OVERVIEW.TXT》，里面有详细的介绍。

最后，我们启动Cygwin，开始编译：

如果你看到了Install:**，这说明你的库已经编译好了。

FAQ 2：
如果编译遇到下面错误，怎么办？

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1. error:redefinitionoftypedef'int8_t'

需要注释掉你的代码中“typedef signed char int8_t;”，如果你的代码之前是已经移植到了Mobile/Symbian上的话，很有可能遇到这个问题。

5.4编写库测试程序

用Eclipse创建一个OPhone工程，在入口类中输入如下代码：

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1. /**
2. *@authorophone
3. *@[e-mail]
4. */
6. packageophone.streaming.video.h264;
8. importjava.io.File;
9. importjava.io.FileInputStream;
10. importjava.io.InputStream;
11. importjava.nio.ByteBuffer;
12. importOPhone.app.Activity;
13. importOPhone.graphics.BitmapFactory;
14. importOPhone.os.Bundle;
15. importOPhone.os.Handler;
16. importOPhone.os.Message;
17. importOPhone.widget.ImageView;
18. importOPhone.widget.TextView;
20. publicclassH264ExampleextendsActivity{
22. privatestaticfinalintVideoWidth=352;
23. privatestaticfinalintVideoHeight=288;
25. privateImageViewImageLayout=null;
26. privateTextViewFPSLayout=null;
27. privateH264decodeDecode=null;
28. privateHandlerH=null;
29. privatebyte[]Buffer=null;
31. privateintDecodeCount=0;
32. privatelongStartTime=0;
34. publicvoidonCreate(BundlesavedInstanceState){
36. super.onCreate(savedInstanceState);
37. setContentView(R.layout.main);
39. ImageLayout=(ImageView)findViewById(R.id.ImageView);
40. FPSLayout=(TextView)findViewById(R.id.TextView);
41. Decode=newH264decode();
43. StartTime=System.currentTimeMillis();
45. newThread(newRunnable(){
46. publicvoidrun(){
47. StartDecode();
48. }
49. }).start();
51. H=newHandler(){
52. publicvoidhandleMessage(Messagemsg){
53. ImageLayout.invalidate();
54. ImageLayout.setImageBitmap(BitmapFactory.decodeByteArray(Buffer,0,Buffer.length));
56. longTime=(System.currentTimeMillis()-StartTime)/1000;
57. if(Time>0){
58. FPSLayout.setText("花费时间:"+Time+"秒解码帧数:"+DecodeCount+"FPS:"+(DecodeCount/Time));
59. }
60. }
61. };
62. }
64. privatevoidStartDecode(){
66. Fileh264file=newFile("/tmp/Demo.264");
67. InputStreamh264stream=null;
68. try{
70. h264stream=newFileInputStream(h264file);
71. ByteBufferpInBuffer=ByteBuffer.allocate(51200);//分配50k的缓存
72. ByteBufferpRGBBuffer=ByteBuffer.allocate(VideoWidth*VideoHeight*3);
74. while(h264stream.read(pInBuffer.array(),pInBuffer.position(),pInBuffer.remaining())>=0){
76. pInBuffer.position(0);
77. do{
78. intDecodeLength=Decode.DecodeOneFrame(pInBuffer,pRGBBuffer);
80. //如果解码成功，把解码出来的图片显示出来
81. if(DecodeLength>0&&pRGBBuffer.position()>0){
83. //转换RGB字节为BMP
84. BMPImagebmp=newBMPImage(pRGBBuffer.array(),VideoWidth,VideoHeight);
85. Buffer=bmp.getByte();
87. H.sendMessage(H.obtainMessage());
89. Thread.sleep(1);
90. DecodeCount++;
91. }
93. }while(pInBuffer.remaining()>10240);//确保缓存区里面的数据始终大于10k
95. //清理已解码缓冲区
96. intRemaining=pInBuffer.remaining();
97. System.arraycopy(pInBuffer.array(),pInBuffer.position(),pInBuffer.array(),0,Remaining);
98. pInBuffer.position(Remaining);
99. }
101. }catch(Exceptione1){
102. e1.printStackTrace();
103. }finally{
104. try{h264stream.close();}catch(Exceptione){}
105. }
107. }
109. protectedvoidonDestroy(){
110. super.onDestroy();
111. Decode.Cleanup();
112. }
113. }

/**
* @author ophone
* @email [e-mail]
*/
package ophone.streaming.video.h264;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.nio.ByteBuffer;
import OPhone.app.Activity;
import OPhone.graphics.BitmapFactory;
import OPhone.os.Bundle;
import OPhone.os.Handler;
import OPhone.os.Message;
import OPhone.widget.ImageView;
import OPhone.widget.TextView;
public class H264Example extends Activity {
private static final int VideoWidth = 352;
private static final int VideoHeight = 288;
private ImageView ImageLayout = null;
private TextView FPSLayout = null;
private H264decode Decode = null;
private Handler H = null;
private byte[] Buffer = null;
private int DecodeCount = 0;
private long StartTime = 0;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageLayout = (ImageView) findViewById(R.id.ImageView);
FPSLayout = (TextView) findViewById(R.id.TextView);
Decode = new H264decode();
StartTime = System.currentTimeMillis();
new Thread(new Runnable(){
public void run() {
StartDecode();
}
}).start();
H = new Handler(){
public void handleMessage(Message msg) {
ImageLayout.invalidate();
ImageLayout.setImageBitmap(BitmapFactory.decodeByteArray(Buffer, 0, Buffer.length));
long Time = (System.currentTimeMillis()-StartTime)/1000;
if(Time > 0){
FPSLayout.setText("花费时间:" + Time + "秒  解码帧数:" + DecodeCount + "  FPS:" + (DecodeCount/Time) );
}
}
};
}
private void StartDecode(){
File h264file = new File("/tmp/Demo.264");
InputStream h264stream = null;
try {
h264stream = new FileInputStream(h264file);
ByteBuffer pInBuffer = ByteBuffer.allocate(51200);//分配50k的缓存
ByteBuffer pRGBBuffer = ByteBuffer.allocate(VideoWidth*VideoHeight*3);
while (h264stream.read(pInBuffer.array(), pInBuffer.position(), pInBuffer.remaining()) >= 0) {
pInBuffer.position(0);
do{
int DecodeLength = Decode.DecodeOneFrame(pInBuffer, pRGBBuffer);
//如果解码成功，把解码出来的图片显示出来
if(DecodeLength > 0 && pRGBBuffer.position() > 0){
//转换RGB字节为BMP
BMPImage bmp = new BMPImage(pRGBBuffer.array(),VideoWidth,VideoHeight);
Buffer = bmp.getByte();
H.sendMessage(H.obtainMessage());
Thread.sleep(1);
DecodeCount ++;
}
}while(pInBuffer.remaining() > 10240);//确保缓存区里面的数据始终大于10k
//清理已解码缓冲区
int Remaining = pInBuffer.remaining();
System.arraycopy(pInBuffer.array(), pInBuffer.position(), pInBuffer.array(), 0, Remaining);
pInBuffer.position(Remaining);
}
} catch (Exception e1) {
e1.printStackTrace();
} finally {
try{h264stream.close();} catch(Exception e){}
}
}
protected void onDestroy() {
super.onDestroy();
Decode.Cleanup();
}
}

BMPImage是一个工具类，主要用于把RGB序列，转换为BMP图象用于显示：

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1. @authorophone
2. *@[e-mail]
3. */
5. packageophone.streaming.video.h264;
7. importjava.nio.ByteBuffer;
9. publicclassBMPImage{
11. //---私有常量
12. privatefinalstaticintBITMAPFILEHEADER_SIZE=14;
13. privatefinalstaticintBITMAPINFOHEADER_SIZE=40;
15. //---位图文件标头
16. privatebytebfType[]={'B','M'};
17. privateintbfSize=0;
18. privateintbfReserved1=0;
19. privateintbfReserved2=0;
20. privateintbfOffBits=BITMAPFILEHEADER_SIZE+BITMAPINFOHEADER_SIZE;
22. //---位图信息标头
23. privateintbiSize=BITMAPINFOHEADER_SIZE;
24. privateintbiWidth=176;
25. privateintbiHeight=144;
26. privateintbiPlanes=1;
27. privateintbiBitCount=24;
28. privateintbiCompression=0;
29. privateintbiSizeImage=biWidth*biHeight*3;
30. privateintbiXPelsPerMeter=0x0;
31. privateintbiYPelsPerMeter=0x0;
32. privateintbiClrUsed=0;
33. privateintbiClrImportant=0;
35. ByteBufferbmpBuffer=null;
37. publicBMPImage(byte[]Data,intWidth,intHeight){
38. biWidth=Width;
39. biHeight=Height;
41. biSizeImage=biWidth*biHeight*3;
42. bfSize=BITMAPFILEHEADER_SIZE+BITMAPINFOHEADER_SIZE+biWidth*biHeight*3;
43. bmpBuffer=ByteBuffer.allocate(BITMAPFILEHEADER_SIZE+BITMAPINFOHEADER_SIZE+biWidth*biHeight*3);
45. writeBitmapFileHeader();
46. writeBitmapInfoHeader();
47. bmpBuffer.put(Data);
48. }
50. publicbyte[]getByte(){
51. returnbmpBuffer.array();
52. }
54. privatebyte[]intToWord(intparValue){
56. byteretValue[]=newbyte[2];
58. retValue[0]=(byte)(parValue&0x00FF);
59. retValue[1]=(byte)((parValue>>8)&0x00FF);
61. return(retValue);
62. }
64. privatebyte[]intToDWord(intparValue){
66. byteretValue[]=newbyte[4];
68. retValue[0]=(byte)(parValue&0x00FF);
69. retValue[1]=(byte)((parValue>>8)&0x000000FF);
70. retValue[2]=(byte)((parValue>>16)&0x000000FF);
71. retValue[3]=(byte)((parValue>>24)&0x000000FF);
73. return(retValue);
75. }
77. privatevoidwriteBitmapFileHeader(){
79. bmpBuffer.put(bfType);
80. bmpBuffer.put(intToDWord(bfSize));
81. bmpBuffer.put(intToWord(bfReserved1));
82. bmpBuffer.put(intToWord(bfReserved2));
83. bmpBuffer.put(intToDWord(bfOffBits));
85. }
87. privatevoidwriteBitmapInfoHeader(){
89. bmpBuffer.put(intToDWord(biSize));
90. bmpBuffer.put(intToDWord(biWidth));
91. bmpBuffer.put(intToDWord(biHeight));
92. bmpBuffer.put(intToWord(biPlanes));
93. bmpBuffer.put(intToWord(biBitCount));
94. bmpBuffer.put(intToDWord(biCompression));
95. bmpBuffer.put(intToDWord(biSizeImage));
96. bmpBuffer.put(intToDWord(biXPelsPerMeter));
97. bmpBuffer.put(intToDWord(biYPelsPerMeter));
98. bmpBuffer.put(intToDWord(biClrUsed));
99. bmpBuffer.put(intToDWord(biClrImportant));
101. }
102. }

@author ophone
* @email [e-mail]
*/
package ophone.streaming.video.h264;
import java.nio.ByteBuffer;
public class BMPImage {
// --- 私有常量
private final static int BITMAPFILEHEADER_SIZE = 14;
private final static int BITMAPINFOHEADER_SIZE = 40;
// --- 位图文件标头
private byte bfType[] = { 'B', 'M' };
private int bfSize = 0;
private int bfReserved1 = 0;
private int bfReserved2 = 0;
private int bfOffBits = BITMAPFILEHEADER_SIZE + BITMAPINFOHEADER_SIZE;
// --- 位图信息标头
private int biSize = BITMAPINFOHEADER_SIZE;
private int biWidth = 176;
private int biHeight = 144;
private int biPlanes = 1;
private int biBitCount = 24;
private int biCompression = 0;
private int biSizeImage = biWidth*biHeight*3;
private int biXPelsPerMeter = 0x0;
private int biYPelsPerMeter = 0x0;
private int biClrUsed = 0;
private int biClrImportant = 0;
ByteBuffer bmpBuffer = null;
public BMPImage(byte[] Data,int Width,int Height){
biWidth = Width;
biHeight = Height;
biSizeImage = biWidth*biHeight*3;
bfSize = BITMAPFILEHEADER_SIZE + BITMAPINFOHEADER_SIZE + biWidth*biHeight*3;
bmpBuffer = ByteBuffer.allocate(BITMAPFILEHEADER_SIZE + BITMAPINFOHEADER_SIZE + biWidth*biHeight*3);
writeBitmapFileHeader();
writeBitmapInfoHeader();
bmpBuffer.put(Data);
}
public byte[] getByte(){
return bmpBuffer.array();
}
private byte[] intToWord(int parValue) {
byte retValue[] = new byte[2];
retValue[0] = (byte) (parValue & 0x00FF);
retValue[1] = (byte) ((parValue >> 8) & 0x00FF);
return (retValue);
}
private byte[] intToDWord(int parValue) {
byte retValue[] = new byte[4];
retValue[0] = (byte) (parValue & 0x00FF);
retValue[1] = (byte) ((parValue >> 8) & 0x000000FF);
retValue[2] = (byte) ((parValue >> 16) & 0x000000FF);
retValue[3] = (byte) ((parValue >> 24) & 0x000000FF);
return (retValue);
}
private void writeBitmapFileHeader () {
bmpBuffer.put(bfType);
bmpBuffer.put(intToDWord (bfSize));
bmpBuffer.put(intToWord (bfReserved1));
bmpBuffer.put(intToWord (bfReserved2));
bmpBuffer.put(intToDWord (bfOffBits));
}
private void writeBitmapInfoHeader () {
bmpBuffer.put(intToDWord (biSize));
bmpBuffer.put(intToDWord (biWidth));
bmpBuffer.put(intToDWord (biHeight));
bmpBuffer.put(intToWord (biPlanes));
bmpBuffer.put(intToWord (biBitCount));
bmpBuffer.put(intToDWord (biCompression));
bmpBuffer.put(intToDWord (biSizeImage));
bmpBuffer.put(intToDWord (biXPelsPerMeter));
bmpBuffer.put(intToDWord (biYPelsPerMeter));
bmpBuffer.put(intToDWord (biClrUsed));
bmpBuffer.put(intToDWord (biClrImportant));
}
}

测试程序完整工程在此暂不提供。

5.5集成测试

集成测试有两点需要注意，在运行程序前，需要把动态库复制到模拟器的/system/lib目录下面，还需要把需要解码的视频传到模拟器的/tmp目录下。
这里要明确的是，OPhone和Symbian的模拟器都做的太不人性化了，Symbian复制一个文件到模拟器中，要进一堆很深的目录，OPhone的 更恼火，需要敲命令把文件传递到模拟器里，说实话，仅在这点上，Mobile的模拟器做的还是非常人性化的。
命令：

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1. PATH=D:"OPhone"OPhoneSDK"tools"
2. adb.exeremount
3. adb.exepushD:"Eclipse"workspace"H264Example"libs"armeabi"libH264Decode.so/system/lib
4. adb.exepushD:"Eclipse"workspace"H264Example"Demo.264/tmp
5. pause

PATH=D:"OPhone"OPhone SDK"tools"
adb.exe remount
adb.exe push D:"Eclipse"workspace"H264Example"libs"armeabi"libH264Decode.so /system/lib
adb.exe push D:"Eclipse"workspace"H264Example"Demo.264 /tmp
pause

这里解释一下abd push命令：
adb push <本地文件路径> <远程文件路径> - 复制文件或者目录到模拟器
在Eclipse中，启动库测试程序，得到画面如下：

FAQ 3：

模拟器黑屏怎么办？
这可能是由于模拟器启动速度比较慢所引起的，所以需要多等一会。希望下个版本能够改进。

原文地址：http://www.ophonesdn.com/article/show/45;jsessionid=306BD3BE92F43DC693BEB09B0234B036

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