Android Media Player-从网络流播放 [英] Android media player - play from network stream

问题描述

我正在尝试制作一个Android媒体播放器，该播放器应该可以播放网络流中的媒体.我知道它可以播放在RTSP或HTTP上流式传输的媒体，但是我的情况有所不同.

I am trying to make an android media player which should play the media from network stream. I know it can play media that is streamed on RTSP or HTTP but my case is different.

我没有任何媒体流服务器，如果要使用它，则必须对其进行修改.

I am not having any media streaming server and if I intend to use one, then I will have to modify it.

我想做的是将从android摄像头捕获的视频流式传输到服务器，对视频进行少量修改(例如更改颜色或应用某些效果等)，然后将其流式传输回电话.因此，通常我的屏幕分为两部分，一个部分用于上游，另一部分用于向下流视频.

What I am trying to do is to stream the video that is being captured from android camera to the server, do little bit of modification in the video (like change color or apply some effect, etc) and stream it back to the phone. So typically my screen is divided in 2 parts, one is for upstreaming and other shows down streamed video.

现在，我正在做的是在sdcard上捕获视频，同时我正在读取视频并将其流式传输到网络上.在网络上，我正在捕获视频(将其保存在文件中[我也可以在服务器上播放视频])并将其发送回手机.在电话上，我可以接收它，但无法弄清楚如何将此流转换为正确的格式，以便可以在 VideoPlayer 中播放它.

Now what I am doing is capturing the video on sdcard and at the same time I am reading it and streaming it to the web. On web part, I am capturing the video (saving it in file [I am also able to play the video on the server]) and sending it back to the phone. On phone I am able to receive it but I am not able to figure out how to convert this stream to the proper format so that I can play it in VideoPlayer.

我还发现 MediaPlayer 提供了一些方法来播放 FileDescriptor 中的视频，因此我可以从套接字创建 FileDescriptor 并将其传递给到 MediaPlayer ?这种方法行得通吗?是否可以在没有RTSP或HTTP的情况下做到这一点?

I also found that MediaPlayer provides some method to play the video from FileDescriptor so can I create a FileDescriptor from the socket and pass it to MediaPlayer? Will this method work? Is it possible to do it without RTSP or HTTP?

推荐答案

    package com.pocketjourney.media;

import java.io.BufferedInputStream;

/**
 * MediaPlayer does not yet support streaming from external URLs so this class provides a pseudo-streaming function
 * by downloading the content incrementally & playing as soon as we get enough audio in our temporary storage.
 */
public class StreamingMediaPlayer {

    private static final int INTIAL_KB_BUFFER =  96*10/8;//assume 96kbps*10secs/8bits per byte

    private TextView textStreamed;

    private ImageButton playButton;

    private ProgressBar progressBar;

    //  Track for display by progressBar
    private long mediaLengthInKb, mediaLengthInSeconds;
    private int totalKbRead = 0;

    // Create Handler to call View updates on the main UI thread.
    private final Handler handler = new Handler();

    private MediaPlayer     mediaPlayer;

    private File downloadingMediaFile; 

    private boolean isInterrupted;

    private Context context;

    private int counter = 0;

    public StreamingMediaPlayer(Context  context,TextView textStreamed, ImageButton playButton, Button  streamButton,ProgressBar    progressBar) 
    {
        this.context = context;
        this.textStreamed = textStreamed;
        this.playButton = playButton;
        this.progressBar = progressBar;
    }

    /**  
     * Progressivly download the media to a temporary location and update the MediaPlayer as new content becomes available.
     */  
    public void startStreaming(final String mediaUrl, long  mediaLengthInKb, long   mediaLengthInSeconds) throws IOException {

        this.mediaLengthInKb = mediaLengthInKb;
        this.mediaLengthInSeconds = mediaLengthInSeconds;

        Runnable r = new Runnable() {   
            public void run() {   
                try {   
                    downloadAudioIncrement(mediaUrl);
                } catch (IOException e) {
                    Log.e(getClass().getName(), "Unable to initialize the MediaPlayer for fileUrl=" + mediaUrl, e);
                    return;
                }   
            }   
        };   
        new Thread(r).start();
    }

    /**  
     * Download the url stream to a temporary location and then call the setDataSource  
     * for that local file
     */  
    public void downloadAudioIncrement(String mediaUrl) throws IOException {

        URLConnection cn = new URL(mediaUrl).openConnection();   
        cn.connect();   
        InputStream stream = cn.getInputStream();
        if (stream == null) {
            Log.e(getClass().getName(), "Unable to create InputStream for mediaUrl:" + mediaUrl);
        }

        downloadingMediaFile = new File(context.getCacheDir(),"downloadingMedia.dat");

        // Just in case a prior deletion failed because our code crashed or something, we also delete any previously 
        // downloaded file to ensure we start fresh.  If you use this code, always delete 
        // no longer used downloads else you'll quickly fill up your hard disk memory.  Of course, you can also 
        // store any previously downloaded file in a separate data cache for instant replay if you wanted as well.
        if (downloadingMediaFile.exists()) {
            downloadingMediaFile.delete();
        }

        FileOutputStream out = new FileOutputStream(downloadingMediaFile);   
        byte buf[] = new byte[16384];
        int totalBytesRead = 0, incrementalBytesRead = 0;
        do {
            int numread = stream.read(buf);   
            if (numread <= 0)   
                break;   
            out.write(buf, 0, numread);
            totalBytesRead += numread;
            incrementalBytesRead += numread;
            totalKbRead = totalBytesRead/1000;

            testMediaBuffer();
            fireDataLoadUpdate();
        } while (validateNotInterrupted());   
            stream.close();
        if (validateNotInterrupted()) {
            fireDataFullyLoaded();
        }
    }  

    private boolean validateNotInterrupted() {
        if (isInterrupted) {
            if (mediaPlayer != null) {
                mediaPlayer.pause();
                //mediaPlayer.release();
            }
            return false;
        } else {
            return true;
        }
    }


    /**
     * Test whether we need to transfer buffered data to the MediaPlayer.
     * Interacting with MediaPlayer on non-main UI thread can causes crashes to so perform this using a Handler.
     */  
    private void  testMediaBuffer() {
        Runnable updater = new Runnable() {
            public void run() {
                if (mediaPlayer == null) {
                    //  Only create the MediaPlayer once we have the minimum buffered data
                    if ( totalKbRead >= INTIAL_KB_BUFFER) {
                        try {
                            startMediaPlayer();
                        } catch (Exception e) {
                            Log.e(getClass().getName(), "Error copying buffered conent.", e);               
                        }
                    }
                } else if ( mediaPlayer.getDuration() - mediaPlayer.getCurrentPosition() <= 1000 ){ 
                    //  NOTE:  The media player has stopped at the end so transfer any existing buffered data
                    //  We test for < 1second of data because the media player can stop when there is still
                    //  a few milliseconds of data left to play
                    transferBufferToMediaPlayer();
                }
            }
        };
        handler.post(updater);
    }

    private void startMediaPlayer() {
        try {   
            File bufferedFile = new File(context.getCacheDir(),"playingMedia" + (counter++) + ".dat");

            // We double buffer the data to avoid potential read/write errors that could happen if the 
            // download thread attempted to write at the same time the MediaPlayer was trying to read.
            // For example, we can't guarantee that the MediaPlayer won't open a file for playing and leave it locked while 
            // the media is playing.  This would permanently deadlock the file download.  To avoid such a deadloack, 
            // we move the currently loaded data to a temporary buffer file that we start playing while the remaining 
            // data downloads.  
            moveFile(downloadingMediaFile,bufferedFile);

            Log.e(getClass().getName(),"Buffered File path: " + bufferedFile.getAbsolutePath());
            Log.e(getClass().getName(),"Buffered File length: " + bufferedFile.length()+"");

            mediaPlayer = createMediaPlayer(bufferedFile);

            // We have pre-loaded enough content and started the MediaPlayer so update the buttons & progress meters.
            mediaPlayer.start();
            startPlayProgressUpdater();         
            playButton.setEnabled(true);
        } catch (IOException e) {
            Log.e(getClass().getName(), "Error initializing the MediaPlayer.", e);
            return;
        }   
    }

    private MediaPlayer createMediaPlayer(File mediaFile)
    throws IOException {
        MediaPlayer mPlayer = new MediaPlayer();
        mPlayer.setOnErrorListener(
                new MediaPlayer.OnErrorListener() {
                    public boolean onError(MediaPlayer mp, int what, int extra) {
                        Log.e(getClass().getName(), "Error in MediaPlayer: (" + what +") with extra (" +extra +")" );
                        return false;
                    }
                });

        //  It appears that for security/permission reasons, it is better to pass a FileDescriptor rather than a direct path to the File.
        //  Also I have seen errors such as "PVMFErrNotSupported" and "Prepare failed.: status=0x1" if a file path String is passed to
        //  setDataSource().  So unless otherwise noted, we use a FileDescriptor here.
        FileInputStream fis = new FileInputStream(mediaFile);
        mPlayer.setDataSource(fis.getFD());
        mPlayer.prepare();
        return mPlayer;
    }

    /**
     * Transfer buffered data to the MediaPlayer.
     * NOTE: Interacting with a MediaPlayer on a non-main UI thread can cause thread-lock and crashes so 
     * this method should always be called using a Handler.
     */  
    private void transferBufferToMediaPlayer() {
        try {
            // First determine if we need to restart the player after transferring data...e.g. perhaps the user pressed pause
            boolean wasPlaying = mediaPlayer.isPlaying();
            int curPosition = mediaPlayer.getCurrentPosition();

            // Copy the currently downloaded content to a new buffered File.  Store the old File for deleting later. 
            File oldBufferedFile = new File(context.getCacheDir(),"playingMedia" + counter + ".dat");
            File bufferedFile = new File(context.getCacheDir(),"playingMedia" + (counter++) + ".dat");

            //  This may be the last buffered File so ask that it be delete on exit.  If it's already deleted, then this won't mean anything.  If you want to 
            // keep and track fully downloaded files for later use, write caching code and please send me a copy.
            bufferedFile.deleteOnExit();   
            moveFile(downloadingMediaFile,bufferedFile);

            // Pause the current player now as we are about to create and start a new one.  So far (Android v1.5),
            // this always happens so quickly that the user never realized we've stopped the player and started a new one
            mediaPlayer.pause();

            // Create a new MediaPlayer rather than try to re-prepare the prior one.
            mediaPlayer = createMediaPlayer(bufferedFile);
            mediaPlayer.seekTo(curPosition);

            //  Restart if at end of prior buffered content or mediaPlayer was previously playing.  
            //  NOTE:  We test for < 1second of data because the media player can stop when there is still
            //  a few milliseconds of data left to play
            boolean atEndOfFile = mediaPlayer.getDuration() - mediaPlayer.getCurrentPosition() <= 1000;
            if (wasPlaying || atEndOfFile){
                mediaPlayer.start();
            }

            // Lastly delete the previously playing buffered File as it's no longer needed.
            oldBufferedFile.delete();

        }catch (Exception e) {
            Log.e(getClass().getName(), "Error updating to newly loaded content.", e);                  
        }
    }

    private void fireDataLoadUpdate() {
        Runnable updater = new Runnable() {
            public void run() {
                textStreamed.setText((totalKbRead + " Kb read"));
                float loadProgress = ((float)totalKbRead/(float)mediaLengthInKb);
                progressBar.setSecondaryProgress((int)(loadProgress*100));
            }
        };
        handler.post(updater);
    }

    private void fireDataFullyLoaded() {
        Runnable updater = new Runnable() { 
            public void run() {
                transferBufferToMediaPlayer();

                // Delete the downloaded File as it's now been transferred to the currently playing buffer file.
                downloadingMediaFile.delete();
                textStreamed.setText(("Audio full loaded: " + totalKbRead + " Kb read"));
            }
        };
        handler.post(updater);
    }

    public MediaPlayer getMediaPlayer() {
        return mediaPlayer;
    }

    public void startPlayProgressUpdater() {
        float progress = (((float)mediaPlayer.getCurrentPosition()/1000)/mediaLengthInSeconds);
        progressBar.setProgress((int)(progress*100));

        if (mediaPlayer.isPlaying()) {
            Runnable notification = new Runnable() {
                public void run() {
                    startPlayProgressUpdater();
                }
            };
            handler.postDelayed(notification,1000);
        }
    }    

    public void interrupt() {
        playButton.setEnabled(false);
        isInterrupted = true;
        validateNotInterrupted();
    }

    /**
     *  Move the file in oldLocation to newLocation.
     */
    public void moveFile(File   oldLocation, File   newLocation)
    throws IOException {

        if ( oldLocation.exists( )) {
            BufferedInputStream  reader = new BufferedInputStream( new FileInputStream(oldLocation) );
            BufferedOutputStream  writer = new BufferedOutputStream( new FileOutputStream(newLocation, false));
            try {
                byte[]  buff = new byte[8192];
                int numChars;
                while ( (numChars = reader.read(  buff, 0, buff.length ) ) != -1) {
                    writer.write( buff, 0, numChars );
                }
            } catch( IOException ex ) {
                throw new IOException("IOException when transferring " + oldLocation.getPath() + " to " + newLocation.getPath());
            } finally {
                try {
                    if ( reader != null ){                      
                        writer.close();
                        reader.close();
                    }
                } catch( IOException ex ){
                    Log.e(getClass().getName(),"Error closing files when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() ); 
                }
            }
        } else {
            throw new IOException("Old location does not exist when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
        }
    }
}

尝试使用此

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