How to fix corrupted video shot with Nokia Lumia 830 Windows 10 mobile

Question

I have few corrupted video clips taken with Nokia Lumia 830 Win 10 mobile. Here is what I did with the clip using FFMPeg:

E:\>ffmpeg -i WP_20160730_12_34_18_Pro.mp4 -c copy WP_20160730_12_34_18_Pro-1.mp4
ffmpeg version N-81312-gb83d907 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.4.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 51.100 / 57. 51.100
  libavformat    57. 46.100 / 57. 46.100
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 50.100 /  6. 50.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
[adp @ 0000000000e36300] Format adp detected only with low score of 25, misdetection possible!
Input #0, adp, from 'WP_20160730_12_34_18_Pro.mp4':
  Duration: 00:08:29.50, start: 0.000000, bitrate: 438 kb/s
    Stream #0:0: Audio: adpcm_dtk, 48000 Hz, stereo, s16p
[mp4 @ 000000000257a140] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
[mp4 @ 000000000257a140] Could not find tag for codec adpcm_dtk in stream #0, codec not currently supported in container
Output #0, mp4, to 'WP_20160730_12_34_18_Pro-1.mp4':
  Metadata:
    encoder         : Lavf57.46.100
    Stream #0:0: Audio: adpcm_dtk, 48000 Hz, stereo
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument

Can anyone explain what my video clip's problem is? I am a newbie in FFMPEG.