android - 使用前置摄像头录制视频时分别获取视频和音频缓冲区

Question

我在 SO 和一些不错的博客文章上挖掘了很多但似乎我有独特的要求单独读取视频和音频缓冲区以便在录制过程中对其进行进一步处理。

我的用例就像当用户开始录制视频时，我需要使用 ML-Face-Detection-Kit 不断处理视频帧，并不断处理音频帧以确保用户正在说些什么并检测噪音水平。为此，我认为我需要将视频和音频都放在一个单独的缓冲区中，并在处理后将其合并并保存到 MP4 文件中作为录音。

我试过了CameraView由伟人开发Mattia Iavarone但它仅提供视频帧。

我愿意接受其他有用的建议/反馈来处理这种情况。

Answer 1

这是一个 answer引用 javaCV 库的 RecordActivity.java示例。

它使用单独的音频和视频线程实时获取帧。

编辑 1:我按照建议包含了 Bytedeco 的 RecordActivity.java 的代码示例。

package org.bytedeco.javacv.recordactivity;

import android.app.Activity;
import android.content.Context;
import android.content.pm.ActivityInfo;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.PowerManager;
import android.util.Log;
import android.view.Display;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ShortBuffer;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.bytedeco.javacpp.avutil;
import org.bytedeco.javacv.FFmpegFrameFilter;
import org.bytedeco.javacv.FFmpegFrameRecorder;
import org.bytedeco.javacv.Frame;
import org.bytedeco.javacv.FrameFilter;

public class RecordActivity extends Activity implements OnClickListener {

    private final static String CLASS_LABEL = "RecordActivity";
    private final static String LOG_TAG = CLASS_LABEL;

    private String ffmpeg_link = "/mnt/sdcard/stream.flv";

    long startTime = 0;
    boolean recording = false;

    private FFmpegFrameRecorder recorder;

    private boolean isPreviewOn = false;

    /*Filter information, change boolean to true if adding a fitler*/
    private boolean addFilter = true;
    private String filterString = "";
    FFmpegFrameFilter filter;

    private int sampleAudioRateInHz = 44100;
    private int imageWidth = 320;
    private int imageHeight = 240;
    private int frameRate = 30;

    /* audio data getting thread */
    private AudioRecord audioRecord;
    private AudioRecordRunnable audioRecordRunnable;
    private Thread audioThread;
    volatile boolean runAudioThread = true;

    /* video data getting thread */
    private Camera cameraDevice;
    private CameraView cameraView;

    private Frame yuvImage = null;

    /* layout setting */
    private final int bg_screen_bx = 232;
    private final int bg_screen_by = 128;
    private final int bg_screen_width = 700;
    private final int bg_screen_height = 500;
    private final int bg_width = 1123;
    private final int bg_height = 715;
    private final int live_width = 640;
    private final int live_height = 480;
    private int screenWidth, screenHeight;
    private Button btnRecorderControl;

    /* The number of seconds in the continuous record loop (or 0 to disable loop). */
    final int RECORD_LENGTH = 0;
    Frame[] images;
    long[] timestamps;
    ShortBuffer[] samples;
    int imagesIndex, samplesIndex;

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

        setContentView(R.layout.main);

        initLayout();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        recording = false;

        if (cameraView != null) {
            cameraView.stopPreview();
        }

        if(cameraDevice != null) {
            cameraDevice.stopPreview();
            cameraDevice.release();
            cameraDevice = null;
        }
    }


    private void initLayout() {

        /* get size of screen */
        Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
        screenWidth = display.getWidth();
        screenHeight = display.getHeight();
        RelativeLayout.LayoutParams layoutParam = null;
        LayoutInflater myInflate = null;
        myInflate = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        RelativeLayout topLayout = new RelativeLayout(this);
        setContentView(topLayout);
        LinearLayout preViewLayout = (LinearLayout) myInflate.inflate(R.layout.main, null);
        layoutParam = new RelativeLayout.LayoutParams(screenWidth, screenHeight);
        topLayout.addView(preViewLayout, layoutParam);

        /* add control button: start and stop */
        btnRecorderControl = (Button) findViewById(R.id.recorder_control);
        btnRecorderControl.setText("Start");
        btnRecorderControl.setOnClickListener(this);

        /* add camera view */
        int display_width_d = (int) (1.0 * bg_screen_width * screenWidth / bg_width);
        int display_height_d = (int) (1.0 * bg_screen_height * screenHeight / bg_height);
        int prev_rw, prev_rh;
        if (1.0 * display_width_d / display_height_d > 1.0 * live_width / live_height) {
            prev_rh = display_height_d;
            prev_rw = (int) (1.0 * display_height_d * live_width / live_height);
        } else {
            prev_rw = display_width_d;
            prev_rh = (int) (1.0 * display_width_d * live_height / live_width);
        }
        layoutParam = new RelativeLayout.LayoutParams(prev_rw, prev_rh);
        layoutParam.topMargin = (int) (1.0 * bg_screen_by * screenHeight / bg_height);
        layoutParam.leftMargin = (int) (1.0 * bg_screen_bx * screenWidth / bg_width);

        cameraDevice = Camera.open();
        Log.i(LOG_TAG, "cameara open");
        cameraView = new CameraView(this, cameraDevice);
        topLayout.addView(cameraView, layoutParam);
        Log.i(LOG_TAG, "cameara preview start: OK");
    }

    //---------------------------------------
    // initialize ffmpeg_recorder
    //---------------------------------------
    private void initRecorder() {

        Log.w(LOG_TAG,"init recorder");

        if (RECORD_LENGTH > 0) {
            imagesIndex = 0;
            images = new Frame[RECORD_LENGTH * frameRate];
            timestamps = new long[images.length];
            for (int i = 0; i < images.length; i++) {
                images[i] = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
                timestamps[i] = -1;
            }
        } else if (yuvImage == null) {
            yuvImage = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
            Log.i(LOG_TAG, "create yuvImage");
        }

        Log.i(LOG_TAG, "ffmpeg_url: " + ffmpeg_link);
        recorder = new FFmpegFrameRecorder(ffmpeg_link, imageWidth, imageHeight, 1);
        recorder.setFormat("flv");
        recorder.setSampleRate(sampleAudioRateInHz);
        // Set in the surface changed method
        recorder.setFrameRate(frameRate);

        // The filterString  is any ffmpeg filter.
        // Here is the link for a list: https://ffmpeg.org/ffmpeg-filters.html
        filterString = "transpose=0";
        filter = new FFmpegFrameFilter(filterString, imageWidth, imageHeight);

        //default format on android
        filter.setPixelFormat(avutil.AV_PIX_FMT_NV21);

        Log.i(LOG_TAG, "recorder initialize success");

        audioRecordRunnable = new AudioRecordRunnable();
        audioThread = new Thread(audioRecordRunnable);
        runAudioThread = true;
    }

    public void startRecording() {

        initRecorder();

        try {
            recorder.start();
            startTime = System.currentTimeMillis();
            recording = true;
            audioThread.start();

            if(addFilter) {
                filter.start();
            }

        } catch (FFmpegFrameRecorder.Exception | FrameFilter.Exception e) {
            e.printStackTrace();
        }
    }

    public void stopRecording() {

        runAudioThread = false;
        try {
            audioThread.join();
        } catch (InterruptedException e) {
            // reset interrupt to be nice
            Thread.currentThread().interrupt();
            return;
        }
        audioRecordRunnable = null;
        audioThread = null;

        if (recorder != null && recording) {
            if (RECORD_LENGTH > 0) {
                Log.v(LOG_TAG,"Writing frames");
                try {
                    int firstIndex = imagesIndex % samples.length;
                    int lastIndex = (imagesIndex - 1) % images.length;
                    if (imagesIndex <= images.length) {
                        firstIndex = 0;
                        lastIndex = imagesIndex - 1;
                    }
                    if ((startTime = timestamps[lastIndex] - RECORD_LENGTH * 1000000L) < 0) {
                        startTime = 0;
                    }
                    if (lastIndex < firstIndex) {
                        lastIndex += images.length;
                    }
                    for (int i = firstIndex; i <= lastIndex; i++) {
                        long t = timestamps[i % timestamps.length] - startTime;
                        if (t >= 0) {
                            if (t > recorder.getTimestamp()) {
                                recorder.setTimestamp(t);
                            }
                            recorder.record(images[i % images.length]);
                        }
                    }

                    firstIndex = samplesIndex % samples.length;
                    lastIndex = (samplesIndex - 1) % samples.length;
                    if (samplesIndex <= samples.length) {
                        firstIndex = 0;
                        lastIndex = samplesIndex - 1;
                    }
                    if (lastIndex < firstIndex) {
                        lastIndex += samples.length;
                    }
                    for (int i = firstIndex; i <= lastIndex; i++) {
                        recorder.recordSamples(samples[i % samples.length]);
                    }
                } catch (FFmpegFrameRecorder.Exception e) {
                    Log.v(LOG_TAG,e.getMessage());
                    e.printStackTrace();
                }
            }

            recording = false;
            Log.v(LOG_TAG,"Finishing recording, calling stop and release on recorder");
            try {
                recorder.stop();
                recorder.release();
                filter.stop();
                filter.release();
            } catch (FFmpegFrameRecorder.Exception | FrameFilter.Exception e) {
                e.printStackTrace();
            }
            recorder = null;

        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (recording) {
                stopRecording();
            }

            finish();

            return true;
        }

        return super.onKeyDown(keyCode, event);
    }


    //---------------------------------------------
    // audio thread, gets and encodes audio data
    //---------------------------------------------
    class AudioRecordRunnable implements Runnable {

        @Override
        public void run() {
            android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);

            // Audio
            int bufferSize;
            ShortBuffer audioData;
            int bufferReadResult;

            bufferSize = AudioRecord.getMinBufferSize(sampleAudioRateInHz,
                    AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
            audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleAudioRateInHz,
                    AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);

            if (RECORD_LENGTH > 0) {
                samplesIndex = 0;
                samples = new ShortBuffer[RECORD_LENGTH * sampleAudioRateInHz * 2 / bufferSize + 1];
                for (int i = 0; i < samples.length; i++) {
                    samples[i] = ShortBuffer.allocate(bufferSize);
                }
            } else {
                audioData = ShortBuffer.allocate(bufferSize);
            }

            Log.d(LOG_TAG, "audioRecord.startRecording()");
            audioRecord.startRecording();

            /* ffmpeg_audio encoding loop */
            while (runAudioThread) {
                if (RECORD_LENGTH > 0) {
                    audioData = samples[samplesIndex++ % samples.length];
                    audioData.position(0).limit(0);
                }
                //Log.v(LOG_TAG,"recording? " + recording);
                bufferReadResult = audioRecord.read(audioData.array(), 0, audioData.capacity());
                audioData.limit(bufferReadResult);
                if (bufferReadResult > 0) {
                    Log.v(LOG_TAG,"bufferReadResult: " + bufferReadResult);
                    // If "recording" isn't true when start this thread, it never get's set according to this if statement...!!!
                    // Why?  Good question...
                    if (recording) {
                        if (RECORD_LENGTH <= 0) try {
                            recorder.recordSamples(audioData);
                            //Log.v(LOG_TAG,"recording " + 1024*i + " to " + 1024*i+1024);
                        } catch (FFmpegFrameRecorder.Exception e) {
                            Log.v(LOG_TAG,e.getMessage());
                            e.printStackTrace();
                        }
                    }
                }
            }
            Log.v(LOG_TAG,"AudioThread Finished, release audioRecord");

            /* encoding finish, release recorder */
            if (audioRecord != null) {
                audioRecord.stop();
                audioRecord.release();
                audioRecord = null;
                Log.v(LOG_TAG,"audioRecord released");
            }
        }
    }

    //---------------------------------------------
    // camera thread, gets and encodes video data
    //---------------------------------------------
    class CameraView extends SurfaceView implements SurfaceHolder.Callback, PreviewCallback {

        private SurfaceHolder mHolder;
        private Camera mCamera;

        public CameraView(Context context, Camera camera) {
            super(context);
            Log.w("camera","camera view");
            mCamera = camera;
            mHolder = getHolder();
            mHolder.addCallback(CameraView.this);
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
            mCamera.setPreviewCallback(CameraView.this);
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                stopPreview();
                mCamera.setPreviewDisplay(holder);
            } catch (IOException exception) {
                mCamera.release();
                mCamera = null;
            }
        }

        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            stopPreview();

            Camera.Parameters camParams = mCamera.getParameters();
            List<Camera.Size> sizes = camParams.getSupportedPreviewSizes();
            // Sort the list in ascending order
            Collections.sort(sizes, new Comparator<Camera.Size>() {

                public int compare(final Camera.Size a, final Camera.Size b) {
                    return a.width * a.height - b.width * b.height;
                }
            });

            // Pick the first preview size that is equal or bigger, or pick the last (biggest) option if we cannot
            // reach the initial settings of imageWidth/imageHeight.
            for (int i = 0; i < sizes.size(); i++) {
                if ((sizes.get(i).width >= imageWidth && sizes.get(i).height >= imageHeight) || i == sizes.size() - 1) {
                    imageWidth = sizes.get(i).width;
                    imageHeight = sizes.get(i).height;
                    Log.v(LOG_TAG, "Changed to supported resolution: " + imageWidth + "x" + imageHeight);
                    break;
                }
            }
            camParams.setPreviewSize(imageWidth, imageHeight);

            Log.v(LOG_TAG,"Setting imageWidth: " + imageWidth + " imageHeight: " + imageHeight + " frameRate: " + frameRate);

            camParams.setPreviewFrameRate(frameRate);
            Log.v(LOG_TAG,"Preview Framerate: " + camParams.getPreviewFrameRate());

            mCamera.setParameters(camParams);

            // Set the holder (which might have changed) again
            try {
                mCamera.setPreviewDisplay(holder);
                mCamera.setPreviewCallback(CameraView.this);
                startPreview();
            } catch (Exception e) {
                Log.e(LOG_TAG, "Could not set preview display in surfaceChanged");
            }
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            try {
                mHolder.addCallback(null);
                mCamera.setPreviewCallback(null);
            } catch (RuntimeException e) {
                // The camera has probably just been released, ignore.
            }
        }

        public void startPreview() {
            if (!isPreviewOn && mCamera != null) {
                isPreviewOn = true;
                mCamera.startPreview();
            }
        }

        public void stopPreview() {
            if (isPreviewOn && mCamera != null) {
                isPreviewOn = false;
                mCamera.stopPreview();
            }
        }

        @Override
        public void onPreviewFrame(byte[] data, Camera camera) {
            if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
                startTime = System.currentTimeMillis();
                return;
            }
            if (RECORD_LENGTH > 0) {
                int i = imagesIndex++ % images.length;
                yuvImage = images[i];
                timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
            }


            /* get video data */
            if (yuvImage != null && recording) {
                ((ByteBuffer)yuvImage.image[0].position(0)).put(data);

                if (RECORD_LENGTH <= 0) try {
                    Log.v(LOG_TAG,"Writing Frame");
                    long t = 1000 * (System.currentTimeMillis() - startTime);
                    if (t > recorder.getTimestamp()) {
                        recorder.setTimestamp(t);
                    }

                    if(addFilter) {
                        filter.push(yuvImage);
                        Frame frame2;
                        while ((frame2 = filter.pull()) != null) {
                            recorder.record(frame2, filter.getPixelFormat());
                        }
                    } else {
                        recorder.record(yuvImage);
                    }
                } catch (FFmpegFrameRecorder.Exception | FrameFilter.Exception e) {
                    Log.v(LOG_TAG,e.getMessage());
                    e.printStackTrace();
                }
            }
        }
    }

    @Override
    public void onClick(View v) {
        if (!recording) {
            startRecording();
            Log.w(LOG_TAG, "Start Button Pushed");
            btnRecorderControl.setText("Stop");
        } else {
            // This will trigger the audio recording loop to stop and then set isRecorderStart = false;
            stopRecording();
            Log.w(LOG_TAG, "Stop Button Pushed");
            btnRecorderControl.setText("Start");
        }
    }
}