Android上的實時視頻流應用程序

Question

我正在嘗試構建一個實時視頻流應用程序，該應用程序可以通過Android傳輸實時視頻。

使用MediaRecorder類，我可以用h263編解碼器以3gp格式捕獲視頻數據。

但是，當我運行我的應用程序和流媒體時，服務器端出現2-3秒的延遲。

爲什麼我會得到這個延遲？是否有任何需要刷新的內部緩衝區？除了使用MediaRecorder類外，是否還有其他方法可以讓視頻流播放？

Answer 1

首先創建這個類。

MediaPlayerDemo_Video.java:- 


package com.videostreaming.player; 

import android.app.Activity; 
import android.content.Intent; 
import android.media.AudioManager; 
import android.media.MediaPlayer; 
import android.media.MediaPlayer.OnBufferingUpdateListener; 
import android.media.MediaPlayer.OnCompletionListener; 
import android.media.MediaPlayer.OnPreparedListener; 
import android.media.MediaPlayer.OnVideoSizeChangedListener; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.widget.Toast; 


public class MediaPlayerDemo_Video extends Activity implements 
     OnBufferingUpdateListener, OnCompletionListener, 
     OnPreparedListener, OnVideoSizeChangedListener, SurfaceHolder.Callback { 

    private String path1 = "http://podcast.20min-tv.ch/podcast/20min/199733.mp4"; 
    // private String path2 = "http://podcast.20min-tv.ch/podcast/20min/199752.mp4"; 
    private String path2 = "http://podcast.20min-tv.ch/podcast/20min/199693.mp4"; 
    private String path = ""; 

    private static final String TAG = "MediaPlayerDemo"; 
    private int mVideoWidth; 
    private int mVideoHeight; 
    private MediaPlayer mMediaPlayer; 
    private SurfaceView mPreview; 
    private SurfaceHolder holder; 
// private String path; 
    private Bundle extras; 
    private static final String MEDIA = "media"; 
    private static final int LOCAL_AUDIO = 1; 
    private static final int STREAM_AUDIO = 2; 
    private static final int RESOURCES_AUDIO = 3; 
    private static final int LOCAL_VIDEO = 4; 
    private static final int STREAM_VIDEO = 5; 
    private boolean mIsVideoSizeKnown = false; 
    private boolean mIsVideoReadyToBePlayed = false; 

    private Bundle bdlReceivedData = null; 
    private Intent self = null; 

    /** 
    * 
    * Called when the activity is first created. 
    */ 
    @Override 
    public void onCreate(Bundle icicle) { 
     super.onCreate(icicle); 
     setContentView(R.layout.mediaplayer_2); 

     mPreview = (SurfaceView) findViewById(R.id.surface); 
     holder = mPreview.getHolder(); 
     holder.addCallback(this); 
     holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 

     extras = getIntent().getExtras(); 

     self = this.getIntent(); 
     bdlReceivedData = self.getExtras(); 

     if (bdlReceivedData != null && bdlReceivedData.getInt("video") > 0) 
     { 
      if (bdlReceivedData.getInt("video") == 1) 
      { 
       Toast.makeText(MediaPlayerDemo_Video.this,"playing Video 1", Toast.LENGTH_SHORT); 
       path = path1; 
      } 
      else if (bdlReceivedData.getInt("video") == 2) 
      { 
       Toast.makeText(MediaPlayerDemo_Video.this,"playing Video 2", Toast.LENGTH_SHORT); 
       path = path2; 
      } 
     } 
    } 

    private void playVideo(Integer Media) { 
     doCleanUp(); 
     try { 

//   switch (Media) { 
//    case LOCAL_VIDEO: 
//     /* 
//      * TODO: Set the path variable to a local media file path. 
//      */ 
//     path = ""; 
//     if (path == "") { 
//      // Tell the user to provide a media file URL. 
//      Toast 
//        .makeText(
//          MediaPlayerDemo_Video.this, 
//          "Please edit MediaPlayerDemo_Video Activity, " 
//            + "and set the path variable to your media file path." 
//            + " Your media file must be stored on sdcard.", 
//          Toast.LENGTH_LONG).show(); 
// 
//     } 
//     break; 
//    case STREAM_VIDEO: 
//     /* 
//      * TODO: Set path variable to progressive streamable mp4 or 
//      * 3gpp format URL. Http protocol should be used. 
//      * Mediaplayer can only play "progressive streamable 
//      * contents" which basically means: 1. the movie atom has to 
//      * precede all the media data atoms. 2. The clip has to be 
//      * reasonably interleaved. 
//      * 
//      */ 
//     path = ""; 
//     if (path == "") { 
//      // Tell the user to provide a media file URL. 
//      Toast 
//        .makeText(
//          MediaPlayerDemo_Video.this, 
//          "Please edit MediaPlayerDemo_Video Activity," 
//            + " and set the path variable to your media file URL.", 
//          Toast.LENGTH_LONG).show(); 
// 
//     } 
// 
//     break; 
// 
// 
//   } 

      // Create a new media player and set the listeners 
      mMediaPlayer = new MediaPlayer(); 
      mMediaPlayer.setDataSource(path); 
      mMediaPlayer.setDisplay(holder); 
      mMediaPlayer.prepare(); 
      mMediaPlayer.setOnBufferingUpdateListener(this); 
      mMediaPlayer.setOnCompletionListener(this); 
      mMediaPlayer.setOnPreparedListener(this); 
      mMediaPlayer.setOnVideoSizeChangedListener(this); 
      mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); 

     } catch (Exception e) { 
      Log.e(TAG, "error: " + e.getMessage(), e); 
     } 
    } 

    public void onBufferingUpdate(MediaPlayer arg0, int percent) { 
     Log.d(TAG, "onBufferingUpdate percent:" + percent); 

    } 

    public void onCompletion(MediaPlayer arg0) { 
     Log.d(TAG, "onCompletion called"); 
    } 

    public void onVideoSizeChanged(MediaPlayer mp, int width, int height) { 
     Log.v(TAG, "onVideoSizeChanged called"); 
     if (width == 0 || height == 0) { 
      Log.e(TAG, "invalid video width(" + width + ") or height(" + height + ")"); 
      return; 
     } 
     mIsVideoSizeKnown = true; 
     mVideoWidth = width; 
     mVideoHeight = height; 
     if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) { 
      startVideoPlayback(); 
     } 
    } 

    public void onPrepared(MediaPlayer mediaplayer) { 
     Log.d(TAG, "onPrepared called"); 
     mIsVideoReadyToBePlayed = true; 
     if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) { 
      startVideoPlayback(); 
     } 
    } 

    public void surfaceChanged(SurfaceHolder surfaceholder, int i, int j, int k) { 
     Log.d(TAG, "surfaceChanged called"); 

    } 

    public void surfaceDestroyed(SurfaceHolder surfaceholder) { 
     Log.d(TAG, "surfaceDestroyed called"); 
    } 


    public void surfaceCreated(SurfaceHolder holder) { 
     Log.d(TAG, "surfaceCreated called"); 
     playVideo(extras.getInt(MEDIA)); 
    } 

    @Override 
    protected void onPause() { 
     super.onPause(); 
     releaseMediaPlayer(); 
     doCleanUp(); 
    } 

    @Override 
    protected void onDestroy() { 
     super.onDestroy(); 
     releaseMediaPlayer(); 
     doCleanUp(); 
    } 

    private void releaseMediaPlayer() { 
     if (mMediaPlayer != null) { 
      mMediaPlayer.release(); 
      mMediaPlayer = null; 
     } 
    } 

    private void doCleanUp() { 
     mVideoWidth = 0; 
     mVideoHeight = 0; 
     mIsVideoReadyToBePlayed = false; 
     mIsVideoSizeKnown = false; 
    } 

    private void startVideoPlayback() { 
     Log.v(TAG, "startVideoPlayback"); 
     holder.setFixedSize(mVideoWidth, mVideoHeight); 
     mMediaPlayer.start(); 
    } 
} 

現在隔壁班

MainMenu.java 


package com.videostreaming.player; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 

public class MainMenu extends Activity { 

    Button btn_videoViewDemo1; 
    Button btn_videoViewDemo2; 
    Button btn_MediaPlayerDemo1;  
    Button btn_MediaPlayerDemo2; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     btn_videoViewDemo1 = (Button)findViewById(R.id.btn_videoViewDemo1); 
     btn_videoViewDemo2 = (Button)findViewById(R.id.btn_videoViewDemo2); 
     btn_MediaPlayerDemo1 = (Button)findViewById(R.id.btn_MediaPlayerDemo1); 
     btn_MediaPlayerDemo2 = (Button)findViewById(R.id.btn_MediaPlayerDemo2); 

     btn_videoViewDemo1.setOnClickListener(new View.OnClickListener(){ 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       Intent Navigation1 = new Intent(MainMenu.this,streamplayer.class); 
       Navigation1.putExtra("video",1); 
       startActivity(Navigation1);    
      } 
     }); 

     btn_videoViewDemo2.setOnClickListener(new View.OnClickListener(){ 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       Intent Navigation1 = new Intent(MainMenu.this,streamplayer.class); 
       Navigation1.putExtra("video",2); 
       startActivity(Navigation1); 
      } 
     }); 

     btn_MediaPlayerDemo1.setOnClickListener(new View.OnClickListener(){ 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       Intent Navigation1 = new Intent(MainMenu.this,MediaPlayerDemo_Video.class); 
       Navigation1.putExtra("video",1); 
       startActivity(Navigation1);    
      } 
     }); 

     btn_MediaPlayerDemo2.setOnClickListener(new View.OnClickListener(){ 
      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       Intent Navigation1 = new Intent(MainMenu.this,MediaPlayerDemo_Video.class); 
       Navigation1.putExtra("video",2); 
       startActivity(Navigation1);    
      } 
     });  
    } 
} 

streamplayer.java

package com.videostreaming.player; 

import android.app.Activity; 
import android.content.Intent; 
import android.net.Uri; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.MediaController; 
import android.widget.Toast; 
import android.widget.VideoView; 

public class streamplayer extends Activity { 
    /** Called when the activity is first created. */ 

    private String path1 = "http://podcast.20min-tv.ch/podcast/20min/199733.mp4"; 
    //private String path2 = "http://podcast.20min-tv.ch/podcast/20min/199752.mp4"; 
    private String path2 = "http://podcast.20min-tv.ch/podcast/20min/199693.mp4"; 
    private String path = ""; 

    //// Method 1 - Default Method 
    private VideoView mVideoView; 

    private Bundle bdlReceivedData = null; 
    private Intent self = null; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     try 
     { 
      setContentView(R.layout.videoview); 
      mVideoView = (VideoView) findViewById(R.id.surface_view); 

      self = this.getIntent(); 
      bdlReceivedData = self.getExtras(); 

      if (bdlReceivedData != null && bdlReceivedData.getInt("video") > 0) 
      { 
       if (bdlReceivedData.getInt("video") == 1) 
       { 
        Toast.makeText(streamplayer.this,"playing Video 1", Toast.LENGTH_SHORT); 
        path = path1; 
       } 
       else if (bdlReceivedData.getInt("video") == 2) 
       { 
        Toast.makeText(streamplayer.this,"playing Video 2", Toast.LENGTH_SHORT); 
        path = path2; 
       } 

       /* 
       * Alternatively,for streaming media you can use 
       * mVideoView.setVideoURI(Uri.parse(URLstring)); 
       */ 

       //mVideoView.setVideoPath(path1); 
       ///ELSE 
       mVideoView.setVideoURI(Uri.parse(path));     
       mVideoView.setMediaController(new MediaController(this)); 
       mVideoView.requestFocus();    
       mVideoView.postInvalidateDelayed(100);   
       mVideoView.start(); 

      } 

     }catch (Exception e) { 
      // TODO: handle exception 
      e.printStackTrace(); 
      Toast.makeText(streamplayer.this,"Error Occured:- " + e.getMessage(),Toast.LENGTH_SHORT).show(); 
     } 
    } 
} 

mediaplayer_2.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <SurfaceView android:id="@+id/surface" 
     android:layout_width="fill_parent" 
     android:layout_height="fill_parent" 
     android:layout_gravity="center"> 
    </SurfaceView> 

</LinearLayout> 

videoview.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"> 

    <VideoView 
     android:id="@+id/surface_view" 
     android:layout_width="fill_parent" 
     android:layout_height="fill_parent" 
     android:layout_gravity="center"/> 

</LinearLayout> 

main.xml中

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" > 

<TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"/> 

    <Button 
     android:id="@+id/btn_videoViewDemo1" 
     android:layout_width="fill_parent" 
     android:layout_height="40dip" 
     android:text="VideoView1" 
     android:layout_margin="10dip"> 
    </Button> 

    <Button 
     android:id="@+id/btn_videoViewDemo2" 
     android:layout_width="fill_parent" 
     android:layout_height="40dip" 
     android:text="VideoView2" 
     android:layout_margin="10dip"> 
    </Button> 

    <Button 
     android:id="@+id/btn_MediaPlayerDemo1" 
     android:layout_width="fill_parent" 
     android:layout_height="40dip" 
     android:text="MediaPlayerDemo1" 
     android:layout_margin="10dip"> 
    </Button> 



    <Button 
     android:id="@+id/btn_MediaPlayerDemo2" 
     android:layout_width="fill_parent" 
     android:layout_height="40dip" 
     android:text="MediaPlayerDemo2" 
     android:layout_margin="10dip"> 
    </Button> 


</LinearLayout> 

Answer 2

如果Android應用效果很好，而且它optimitzed的代碼，這延遲的可證明的原因是你是將大量數據發送到服務器，並且對服務器的HTTP請求具有要發送的MB的限制。當這種情況發生時，該類自動或程序員必須將HTTP請求分成多個HTTP請求，顯然它更慢。

Answer 3

如果您在Android上設置RTMP流媒體，最好的解決方案是MediaCodec + FFmpeg + librtmp。這避免了任何hacky「檢測字節流內的NAL單元」業務，但需要Android 4.3。冰球在哪裏去...

我開發了一個open source SDK演示RTMP流與FFmpeg + librtmp as pre-built shared libraries。該SDK專注於HLS流式傳輸，但存在RTMP支持。

如果您希望自己爲Android構建FFmpeg（帶或不帶librtmp），check out my guide。