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

Answer 1

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.