我希望以Periscope的方式进行直播。我在网上做了一个快速搜索，发现像ffmpeg一样的库使用本机库，但根据MediaCodec编码应该直接支持Android SDK吗？
https://developer.android.com/reference/android/media/MediaCodec.html
所以我想知道为什么编码需要外部本机库？
此外我尝试了一些库，但它们似乎太慢了，特别是对于高比特率（我在Nexus 5X上以2500Kbps获得16个fps和1280x720而我希望达到1080），流行的广播应用程序如何做到这一点？
由于涉及如此多的处理，似乎无法使用普通电话（不是顶级电话）实现高质量的流媒体。
答案 0 :(得分：1)
MediaCodec API在高分辨率流中往往变慢。我建议你应该使用FFmpeg，有一个很好的java包装器叫JavaCV（它也适用于android）。这是一个简短的样本，可以让你去
public class MainActivity extends Activity implements OnClickListener {
private PowerManager.WakeLock mWakeLock;
private String ffmpeg_link = "rtmp://live:live@128.122.151.108:1935/live/test.flv";
private volatile FFmpegFrameRecorder recorder;
boolean recording = false;
long startTime = 0;
private int sampleAudioRateInHz = 44100;
private int imageWidth = 320;
private int imageHeight = 240;
private int frameRate = 30;
private Thread audioThread;
volatile boolean runAudioThread = true;
private AudioRecord audioRecord;
private AudioRecordRunnable audioRecordRunnable;
private CameraView cameraView;
private IplImage yuvIplimage = null;
private Button recordButton;
private LinearLayout mainLayout;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
setContentView(R.layout.activity_main);
initLayout();
initRecorder();
}
@Override
protected void onResume() {
super.onResume();
if (mWakeLock == null) {
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK, LOG_TAG);
mWakeLock.acquire();
}
}
@Override
protected void onPause() {
super.onPause();
if (mWakeLock != null) {
mWakeLock.release();
mWakeLock = null;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
recording = false;
}
private void initLayout() {
mainLayout = (LinearLayout) this.findViewById(R.id.record_layout);
recordButton = (Button) findViewById(R.id.recorder_control);
recordButton.setText("Start");
recordButton.setOnClickListener(this);
cameraView = new CameraView(this);
LinearLayout.LayoutParams layoutParam = new LinearLayout.LayoutParams(imageWidth, imageHeight);
mainLayout.addView(cameraView, layoutParam);
Log.v(LOG_TAG, "added cameraView to mainLayout");
}
private void initRecorder() {
Log.w(LOG_TAG,"initRecorder");
if (yuvIplimage == null) {
// Recreated after frame size is set in surface change method
yuvIplimage = IplImage.create(imageWidth, imageHeight, IPL_DEPTH_8U, 2);
//yuvIplimage = IplImage.create(imageWidth, imageHeight, IPL_DEPTH_32S, 2);
Log.v(LOG_TAG, "IplImage.create");
}
recorder = new FFmpegFrameRecorder(ffmpeg_link, imageWidth, imageHeight, 1);
Log.v(LOG_TAG, "FFmpegFrameRecorder: " + ffmpeg_link + " imageWidth: " + imageWidth + " imageHeight " + imageHeight);
recorder.setFormat("flv");
Log.v(LOG_TAG, "recorder.setFormat(\"flv\")");
recorder.setSampleRate(sampleAudioRateInHz);
Log.v(LOG_TAG, "recorder.setSampleRate(sampleAudioRateInHz)");
// re-set in the surface changed method as well
recorder.setFrameRate(frameRate);
Log.v(LOG_TAG, "recorder.setFrameRate(frameRate)");
// Create audio recording thread
audioRecordRunnable = new AudioRecordRunnable();
audioThread = new Thread(audioRecordRunnable);
}
// Start the capture
public void startRecording() {
try {
recorder.start();
startTime = System.currentTimeMillis();
recording = true;
audioThread.start();
} catch (FFmpegFrameRecorder.Exception e) {
e.printStackTrace();
}
}
public void stopRecording() {
// This should stop the audio thread from running
runAudioThread = false;
if (recorder != null && recording) {
recording = false;
Log.v(LOG_TAG,"Finishing recording, calling stop and release on recorder");
try {
recorder.stop();
recorder.release();
} catch (FFmpegFrameRecorder.Exception e) {
e.printStackTrace();
}
recorder = null;
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
// Quit when back button is pushed
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (recording) {
stopRecording();
}
finish();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
public void onClick(View v) {
if (!recording) {
startRecording();
Log.w(LOG_TAG, "Start Button Pushed");
recordButton.setText("Stop");
} else {
stopRecording();
Log.w(LOG_TAG, "Stop Button Pushed");
recordButton.setText("Start");
}
}
//---------------------------------------------
// audio thread, gets and encodes audio data
//---------------------------------------------
class AudioRecordRunnable implements Runnable {
@Override
public void run() {
// Set the thread priority
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
// Audio
int bufferSize;
short[] audioData;
int bufferReadResult;
bufferSize = AudioRecord.getMinBufferSize(sampleAudioRateInHz,
AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT);
audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleAudioRateInHz,
AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);
audioData = new short[bufferSize];
Log.d(LOG_TAG, "audioRecord.startRecording()");
audioRecord.startRecording();
// Audio Capture/Encoding Loop
while (runAudioThread) {
// Read from audioRecord
bufferReadResult = audioRecord.read(audioData, 0, audioData.length);
if (bufferReadResult > 0) {
//Log.v(LOG_TAG,"audioRecord bufferReadResult: " + bufferReadResult);
// Changes in this variable may not be picked up despite it being "volatile"
if (recording) {
try {
// Write to FFmpegFrameRecorder
recorder.record(ShortBuffer.wrap(audioData, 0, bufferReadResult));
} catch (FFmpegFrameRecorder.Exception e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
}
}
Log.v(LOG_TAG,"AudioThread Finished");
/* Capture/Encoding finished, release recorder */
if (audioRecord != null) {
audioRecord.stop();
audioRecord.release();
audioRecord = null;
Log.v(LOG_TAG,"audioRecord released");
}
}
}
class CameraView extends SurfaceView implements SurfaceHolder.Callback, PreviewCallback {
private boolean previewRunning = false;
private SurfaceHolder holder;
private Camera camera;
private byte[] previewBuffer;
long videoTimestamp = 0;
Bitmap bitmap;
Canvas canvas;
public CameraView(Context _context) {
super(_context);
holder = this.getHolder();
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
camera = Camera.open();
try {
camera.setPreviewDisplay(holder);
camera.setPreviewCallback(this);
Camera.Parameters currentParams = camera.getParameters();
Log.v(LOG_TAG,"Preview Framerate: " + currentParams.getPreviewFrameRate());
Log.v(LOG_TAG,"Preview imageWidth: " + currentParams.getPreviewSize().width + " imageHeight: " + currentParams.getPreviewSize().height);
// Use these values
imageWidth = currentParams.getPreviewSize().width;
imageHeight = currentParams.getPreviewSize().height;
frameRate = currentParams.getPreviewFrameRate();
bitmap = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ALPHA_8);
/*
Log.v(LOG_TAG,"Creating previewBuffer size: " + imageWidth * imageHeight * ImageFormat.getBitsPerPixel(currentParams.getPreviewFormat())/8);
previewBuffer = new byte[imageWidth * imageHeight * ImageFormat.getBitsPerPixel(currentParams.getPreviewFormat())/8];
camera.addCallbackBuffer(previewBuffer);
camera.setPreviewCallbackWithBuffer(this);
*/
camera.startPreview();
previewRunning = true;
}
catch (IOException e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
Log.v(LOG_TAG,"Surface Changed: width " + width + " height: " + height);
// We would do this if we want to reset the camera parameters
/*
if (!recording) {
if (previewRunning){
camera.stopPreview();
}
try {
//Camera.Parameters cameraParameters = camera.getParameters();
//p.setPreviewSize(imageWidth, imageHeight);
//p.setPreviewFrameRate(frameRate);
//camera.setParameters(cameraParameters);
camera.setPreviewDisplay(holder);
camera.startPreview();
previewRunning = true;
}
catch (IOException e) {
Log.e(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
*/
// Get the current parameters
Camera.Parameters currentParams = camera.getParameters();
Log.v(LOG_TAG,"Preview Framerate: " + currentParams.getPreviewFrameRate());
Log.v(LOG_TAG,"Preview imageWidth: " + currentParams.getPreviewSize().width + " imageHeight: " + currentParams.getPreviewSize().height);
// Use these values
imageWidth = currentParams.getPreviewSize().width;
imageHeight = currentParams.getPreviewSize().height;
frameRate = currentParams.getPreviewFrameRate();
// Create the yuvIplimage if needed
yuvIplimage = IplImage.create(imageWidth, imageHeight, IPL_DEPTH_8U, 2);
//yuvIplimage = IplImage.create(imageWidth, imageHeight, IPL_DEPTH_32S, 2);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
try {
camera.setPreviewCallback(null);
previewRunning = false;
camera.release();
} catch (RuntimeException e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
if (yuvIplimage != null && recording) {
videoTimestamp = 1000 * (System.currentTimeMillis() - startTime);
// Put the camera preview frame right into the yuvIplimage object
yuvIplimage.getByteBuffer().put(data);
// FAQ about IplImage:
// - For custom raw processing of data, getByteBuffer() returns an NIO direct
// buffer wrapped around the memory pointed by imageData, and under Android we can
// also use that Buffer with Bitmap.copyPixelsFromBuffer() and copyPixelsToBuffer().
// - To get a BufferedImage from an IplImage, we may call getBufferedImage().
// - The createFrom() factory method can construct an IplImage from a BufferedImage.
// - There are also a few copy*() methods for BufferedImage<->IplImage data transfers.
// Let's try it..
// This works but only on transparency
// Need to find the right Bitmap and IplImage matching types
/*
bitmap.copyPixelsFromBuffer(yuvIplimage.getByteBuffer());
//bitmap.setPixel(10,10,Color.MAGENTA);
canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.GREEN);
float leftx = 20;
float topy = 20;
float rightx = 50;
float bottomy = 100;
RectF rectangle = new RectF(leftx,topy,rightx,bottomy);
canvas.drawRect(rectangle, paint);
bitmap.copyPixelsToBuffer(yuvIplimage.getByteBuffer());
*/
//Log.v(LOG_TAG,"Writing Frame");
try {
// Get the correct time
recorder.setTimestamp(videoTimestamp);
// Record the image into FFmpegFrameRecorder
recorder.record(yuvIplimage);
} catch (FFmpegFrameRecorder.Exception e) {
Log.v(LOG_TAG,e.getMessage());
e.printStackTrace();
}
}
}
}
}
答案 1 :(得分：0)
你是对的。您必须考虑 Android ndk 来处理密集型内容。
研究并构建这个yt watchme和minicap。也
走过webrtc
另一个rticonnextdds videodemo android