MediaRecorder start error codes

Question

I want to record raw h.264 video without sound and possibly HW accelerated (and stream it later). So I decided to use `MediaRecorder` (and the socket hack for streaming). I have the following code: ``` final MediaRecorder recorder = new MediaRecorder(); final Camera camera = Camera.open(); camera.unlock(); recorder.setCamera(camera); recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA); recorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT); recorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264); final CamcorderProfile profile = CamcorderProfile.get(CamcorderProfile.QUALITY_LOW); recorder.setVideoSize(profile.videoFrameWidth, profile.videoFrameHeight); recorder.setVideoFrameRate(profile.videoFrameRate); recorder.setVideoEncodingBitRate(profile.videoBitRate); recorder.prepare(); recorder.start(); ``` And bam! This in logcat: ``` E/MediaRecorder﹕ start failed: -38 ``` I started googling, and found plenty of questions and answers, but none about my error code `-38`. So I tr…

Accepted Answer

Alright, I think I have an answer for you. The start function that is failing is defined in a file called `mediarecorder.cpp`. Found here:

```
frameworks/av/media/libmedia/mediarecorder.cpp
```

This start function returns a variable of type `status_t`, and corresponds to the error that you're seeing thrown.

Now, the type `status_t` is defined in a file called `Errors.h` which can be found here:

```
system/core/include/utils/Errors.h
```

This defines an enumeration that corresponds to `status_t` as seen here:

```
enum {
    OK                = 0,    // Everything's swell.
    NO_ERROR          = 0,    // No errors.

UNKNOWN_ERROR       = 0x80000000,

NO_MEMORY           = -ENOMEM,
    INVALID_OPERATION   = -ENOSYS,
    BAD_VALUE           = -EINVAL,
    BAD_TYPE            = 0x80000001,
    NAME_NOT_FOUND      = -ENOENT,
    PERMISSION_DENIED   = -EPERM,
    NO_INIT             = -ENODEV,
    ALREADY_EXISTS      = -EEXIST,
    DEAD_OBJECT         = -EPIPE,
    FAILED_TRANSACTION  = 0x80000002,
    JPARKS_BROKE_IT     = -EPIPE,
#if !defined(HAVE_MS_C_RUNTIME)
    BAD_INDEX           = -EOVERFLOW,
    NOT_ENOUGH_DATA     = -ENODATA,
    WOULD_BLOCK         = -EWOULDBLOCK, 
    TIMED_OUT           = -ETIMEDOUT,
    UNKNOWN_TRANSACTION = -EBADMSG,
#else    
    BAD_INDEX           = -E2BIG,
    NOT_ENOUGH_DATA     = 0x80000003,
    WOULD_BLOCK         = 0x80000004,
    TIMED_OUT           = 0x80000005,
    UNKNOWN_TRANSACTION = 0x80000006,
#endif    
    FDS_NOT_ALLOWED     = 0x80000007,
};
```

As you can see, some of the values here are taken from `errno.h`, so we just need to see which one equates to a value of 38.

According to this source, 38 corresponds to `ENOSYS`. So, if we look back at the status_t enumeration, we can see that in android, `ENOSYS` corresponds to an invalid operation. Not terribly helpful, but I hope this at least points you in the right direction.

MediaRecorder start error codes

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