Android录制没有音频的视频

Question

Android 是否可以在没有音频流的情况下从相机录制视频？

目标：减小输出文件大小。

Answer 1

您可以通过从内置配置文件 (CamcorderProfile) 中复制必填字段来准备 MediaRecorder。只需忽略音频设置，您就可以开始使用了。根据您的需要编辑下面的代码，第 3 步是这里的重要部分。

private boolean prepareVideoRecorder() {

    mCamera = getCameraInstance();
    mMediaRecorder = new MediaRecorder();

    // store the quality profile required
    CamcorderProfile profile = CamcorderProfile.get(cameraid, CamcorderProfile.QUALITY_HIGH);

    // Step 1: Unlock and set camera to MediaRecorder
    mCamera.unlock();
    mMediaRecorder.setCamera(mCamera);

    // Step 2: Set sources
    mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);

    // Step 3: Set all values contained in profile except audio settings
    mMediaRecorder.setOutputFormat(profile.fileFormat);
    mMediaRecorder.setVideoEncoder(profile.videoCodec);
    mMediaRecorder.setVideoEncodingBitRate(profile.videoBitRate);
    mMediaRecorder.setVideoFrameRate(profile.videoFrameRate);
    mMediaRecorder.setVideoSize(profile.videoFrameWidth, profile.videoFrameHeight);

    // Step 4: Set output file
    mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());

    // Step 5: Set the preview output
    mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());

    // Step 6: Prepare configured MediaRecorder
    try {
        mMediaRecorder.prepare();
    } catch (IllegalStateException e) {
        releaseMediaRecorder();
        return false;
    } catch (IOException e) {
        releaseMediaRecorder();
        return false;
    }
    return true;
}

Answer 2

您可以使用 MediaRecorder 而无需对其调用 setAudio*。这是我第一次使用 MediaRecorder，但这个例子似乎有效：

public class CamcorderView extends SurfaceView implements
        SurfaceHolder.Callback {

    private SurfaceHolder mHolder;

    private Camera mCamera;
    private MediaRecorder mRecorder;

    public CamcorderView(Context context, AttributeSet attrs) {
        super(context, attrs);

        mHolder = getHolder();
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        mHolder.addCallback(this);

        mCamera = Camera.open();
        mRecorder = new MediaRecorder();

    }

    public void stop() {
        mRecorder.stop();
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        mCamera.unlock();
        mRecorder.setCamera(mCamera);

        mRecorder.setPreviewDisplay(mHolder.getSurface());

        // You may want to change these
        mRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
        mRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);

        // You'll definitely want to change this
        mRecorder.setOutputFile("/mnt/sdcard/out");

        try {
            mRecorder.prepare();
        } catch (IllegalStateException e) {
            Log.e("IllegalStateException", e.toString());
        } catch (IOException e) {
            Log.e("IOException", e.toString());
        }
        mRecorder.start();

    }
}

您可能还想致电：

• setVideoSize(int, int);
• setVideoFrameRate(int);