Android 实时视频编码—H.264硬编码

阳光穿透心脏的1/2处 2022-07-14 19:10 514阅读 0赞

# [【流媒體】 Android 实时视频编码—H.264硬编码][Android _H.264] #

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# 【流媒體】 Android 实时视频编码—H.264硬编码 #

SkySeraph Apr 4th 2012

Email：skyseraph00@163[.com][]

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## 1 硬编码 & 软编码 ##

硬编码：通过调用Android系统自带的Camera录制视频，实际上是调用了底层的高清编码硬件模块，也即显卡，不使用CPU，速度快

软编码：使用CPU进行编码，如常见C/C++代码，一般编译生成的二进制都是的，速度相对较慢。例如使用Android NDK编译H264生成so库，编写jni接口，再使用java调用so库。

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## 2 原理 ##

① 过程：通过MediaRecoder采集视频，再将视频流映射到LocalSocket实现收发

② 原理：详见[【流媒體】H264—MP4格式及在MP4文件中提取H264的SPS、PPS及码流][H264_MP4_MP4_H264_SPS_PPS] 和 [“【流媒體】Android 实时视频采集—MediaRecoder录制 ”][Android _MediaRecoder_]

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## 3 核心代码 ##

### ① MediaRecoder视频采集 ###

视频采集采用了MediaRecorde录制方式，详见 [“【流媒體】Android 实时视频采集—MediaRecoder录制 ”][Android _MediaRecoder_]

### ② 在initiativeVideo中setOutputFile设置以流方式输出 ###

![复制代码][copycode.gif]

// 设置输出文件方式： 直接本地存储   or LocalSocket远程输出        
                if (bIfNativeORRemote == true) // Native
                {
         
                    lVideoFileFullPath = strRecVideoFilePath + String.valueOf(System.currentTimeMillis())
                            + lVideoFileFullPath;
                    mRecVideoFile = new File(lVideoFileFullPath);
                    // mMediaRecorder.setOutputFile(mRecVideoFile.getAbsolutePath());
                    mMediaRecorder.setOutputFile(mRecVideoFile.getPath()); // called after set**Source before prepare
                    Log.i(TAG, "start write into file~");
                } 
                else // Remote
                {
         
                    mMediaRecorder.setOutputFile(sender.getFileDescriptor()); // 设置以流方式输出
                    Log.i(TAG, "start send into sender~");
                }

![复制代码][copycode.gif]

### ③ startRecording ###

功能：通过这个函数启动线程实现视频流映射到LocalSocket，同时实现编码

private void startRecording()
        {
         
            Log.i(TAG, "##startRecording....");
            new Thread(this).start();            
        }

### run： ###

![复制代码][copycode.gif]

@Override
        public void run()
        {
         
            Log.i(TAG, "##run....");
            
            // defines
            DataInputStream dataInputStream = null;        
            int offSet=0,tmp=0,beLeft=0;
    
            try
            {
         
                dataInputStream = new DataInputStream(receiver.getInputStream());
            } catch (IOException e2)
            {
         
                // TODO Auto-generated catch block
                e2.printStackTrace();
            }    
            try
            {
         
                Thread.currentThread().sleep(500);
            } catch (InterruptedException e1)
            {
         
                e1.printStackTrace();
            }
            
            // ①方式一：通过查看预先录制的视频，需要跳过mdat前面32个字节（不同硬件平台不同！）
            try
            {            
                dataInputStream.read(h264frame, 0, 32); 
                Log.i(TAG, "read mdat from");
            } catch (IOException e1)
            {
         
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            // ②方式二：自动化查找（待补充）
                    
    
            try
            {
         
                h264FileOutputStream = new FileOutputStream("/sdcard/avss/h264.264");//264码流
                Log.i(TAG, "h264FileOutputStream");
            } catch (FileNotFoundException e)
            {
         
                // TODO Auto-generated catch block
                e.printStackTrace();
            }    
            try
            {
         
                h264FileOutputStream.write(h264head);
                h264FileOutputStream.write(h264sps);
                h264FileOutputStream.write(h264head);
                h264FileOutputStream.write(h264pps);
                Log.i(TAG, "run-write SPS/PPS to file");
            } catch (IOException e1)
            {
         
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
    
            while (bIfRecInProcess && (!bIfNativeORRemote))
            {
         
                try
                {
         
                    Log.i(TAG, "**while...");    
                    int h264length = dataInputStream.readInt(); 
                    Log.i(TAG, "h264length:"+h264length);
                    tmp=0; offSet = 0; beLeft = 0;
                    
                    h264FileOutputStream.write(h264head);
                    while (offSet < h264length)
                    {
         
                        beLeft = h264length - offSet;
                        tmp = dataInputStream.read(h264frame, 0, READ_SIZE < beLeft ? READ_SIZE : beLeft);
                        Log.i(TAG, String.format("H264 %d,%d,%d", h264length, offSet, tmp));
                        offSet += tmp;
                        h264FileOutputStream.write(h264frame, 0, tmp);
                    }
                    
                } catch (Exception e)
                {
         
                    // TODO: handle exception
                    e.printStackTrace();
                }
            }        
            //
        }

![复制代码][copycode.gif]

###  ###

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## 4 Ref/Related ##

1 [http://blog.csdn.net/zblue78/article/details/6078040][http_blog.csdn.net_zblue78_article_details_6078040]

2 [http://blog.csdn.net/zblue78/article/details/6083374][http_blog.csdn.net_zblue78_article_details_6083374]

3 [http://www.docin.com/p-282454756.html][http_www.docin.com_p-282454756.html]

4 [http://blog.csdn.net/qwertyuj/article/details/7029836][http_blog.csdn.net_qwertyuj_article_details_7029836]

5 [http://www.cnblogs.com/skyseraph/archive/2012/03/31/2427593.html][Android _MediaRecoder_]

6 [http://www.cnblogs.com/skyseraph/archive/2012/03/23/2415018.html][http_www.cnblogs.com_skyseraph_archive_2012_03_23_2415018.html]

7 [http://www.cnblogs.com/skyseraph/archive/2012/04/01/2429384.html][H264_MP4_MP4_H264_SPS_PPS]

[Android _H.264]: http://www.cnblogs.com/skyseraph/archive/2012/04/04/2431771.html
[.com]: mailto:zgzhaobo@gmail.com
[H264_MP4_MP4_H264_SPS_PPS]: http://www.cnblogs.com/skyseraph/archive/2012/04/01/2429384.html
[Android _MediaRecoder_]: http://www.cnblogs.com/skyseraph/archive/2012/03/31/2427593.html
[copycode.gif]: /images/20220709/5445c6f5fc7647339fd36487680664c5.png
[http_blog.csdn.net_zblue78_article_details_6078040]: http://blog.csdn.net/zblue78/article/details/6078040
[http_blog.csdn.net_zblue78_article_details_6083374]: http://blog.csdn.net/zblue78/article/details/6083374
[http_www.docin.com_p-282454756.html]: http://www.docin.com/p-282454756.html
[http_blog.csdn.net_qwertyuj_article_details_7029836]: http://blog.csdn.net/qwertyuj/article/details/7029836
[http_www.cnblogs.com_skyseraph_archive_2012_03_23_2415018.html]: http://www.cnblogs.com/skyseraph/archive/2012/03/23/2415018.html