MediaRecorder 启动失败：-16

Question

所以我意识到 MediaRecorder 启动错误有很多解决方案，但其中大多数都围绕“启动失败：-19”，它已链接到“NO_INIT”See comments in selected answer here。我没有找到任何解决方案，甚至没有找到-16的解释。

如果有人知道我在哪里可以找到这些错误代码的名称，或者有代码 -16 的解决方案，请将答案放在这里！！这是我正在使用的代码。 （HTC 迅雷，股票）

mr.setVideoSource(MediaRecorder.VideoSource.CAMERA); //mr is my mediaRecorder
mr.setAudioSource(MediaRecorder.AudioSource.MIC);
mr.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
mr.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
mr.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
mr.setOutputFile(ParcelFileDescriptor.fromSocket(soc).getFileDescriptor());  //soc is a java.net.ServerSocket pointing to a port on the device

mr.setVideoSize(480,800);
mr.setVideoFrameRate(5);
mr.prepare();
mr.start(); //Crashes with "start failed: -16"

LOGCAT

07-11 10:14:34.879: V/MediaRecorderJNI(17939): JNIMediaRecorderListener::setCamera
07-11 10:14:34.879: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.549: V/MediaRecorderJNI(17939): setVideoSource(1)
07-11 10:14:47.549: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): setAudioSource(1)
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): setOutputFormat(0)
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): setVideoEncoder(0)
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): setAudioEncoder(0)
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): setVideoFrameRate(5)
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): setOutputFile
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): prepare
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.559: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:47.559: V/MediaRecorderJNI(17939): start
07-11 10:14:47.559: V/MediaRecorderJNI(17939): getMediaRecorder E
07-11 10:14:47.639: E/MediaRecorder(17939): start failed: -16
07-11 10:14:47.639: V/MediaRecorderJNI(17939): process_media_recorder_call
07-11 10:14:59.290: W/dalvikvm(17939): threadid=10: thread exiting with uncaught exception (group=0x4001d5a0)

更新 07/11/12 下午 2:21：发现错误代码 -16 实际上是 -EBUSY。在扩展 LogCat 以包含所有内容并彻底梳理 Android 源代码后，我发现它与无法调整（初始化）相机设置有关，我不确定我做错了什么，但它是一个开始。如果您可以访问 AOSP，您可以看到错误来自 /frameworks/av/media/libstagefright/CameraSource.cpp CameraSource::ConfigureCamera

Answer 1

我遇到了这个错误（启动时为-16），发现它是由使用不受支持的分辨率引起的。

首先您必须从支持的尺寸中获得最佳尺寸

Parameters params = camera.getParameters();
        List<Size> sizes = params.getSupportedPreviewSizes();
        optimalSize = getOptimalPreviewSize(sizes, width, height);
params.setPreviewSize(optimalSize.width, optimalSize.height);

然后确保将预览和视频都设置为相同的大小（如果在我的经验中它们不同，则在视频录制开始时预览会冻结）：

mediaRecorder.setVideoSize(optimalSize.width, optimalSize.height);

（getOptimalPreviewSize 的示例代码来自android sdk）

private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
    final double ASPECT_TOLERANCE = 0.1;
    double targetRatio = (double) w / h;
    if (sizes == null) return null;

    Size optimalSize = null;
    double minDiff = Double.MAX_VALUE;

    int targetHeight = h;

    // Try to find an size match aspect ratio and size
    for (Size size : sizes) {
        double ratio = (double) size.width / size.height;
        if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
        if (Math.abs(size.height - targetHeight) < minDiff) {
            optimalSize = size;
            minDiff = Math.abs(size.height - targetHeight);
        }
    }

    // Cannot find the one match the aspect ratio, ignore the requirement
    if (optimalSize == null) {
        minDiff = Double.MAX_VALUE;
        for (Size size : sizes) {
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
    }
    return optimalSize;
}