svq3: reject/support files protected with "media key"

[ami_stuff]

media key is "test"

​https://forum.videolan.org/viewtopic.php?t=122112

C:\>ffmpeg -i 2_mediakey_test.mov out.avi
ffmpeg version 3.2.git Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 4.6.2 (GCC)
  configuration: --disable-pthreads --enable-gpl --disable-ffprobe
  libavutil      55. 43.100 / 55. 43.100
  libavcodec     57. 72.100 / 57. 72.100
  libavformat    57. 62.100 / 57. 62.100
  libavdevice    57.  2.100 / 57.  2.100
  libavfilter     6. 69.100 /  6. 69.100
  libswscale      4.  3.101 /  4.  3.101
  libswresample   2.  4.100 /  2.  4.100
  libpostproc    54.  2.100 / 54.  2.100
[svq3 @ 0667d5c0] Warning: not compiled with thread support, using thread emulat
ion
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2_mediakey_test.mov':
  Metadata:
    creation_time   : 2017-01-21T07:17:58.000000Z
  Duration: 00:00:00.07, bitrate: 187 kb/s
    Stream #0:0(eng): Video: svq3 (SVQ3 / 0x33515653), yuvj420p(pc), 32x32, 99 k
b/s, 15 fps, 15 tbr, 600 tbn, 600 tbc (default)
    Metadata:
      creation_time   : 2017-01-21T07:17:58.000000Z
      handler_name    : Apple Alias Data Handler
      encoder         : Sorenson Video 3
[svq3 @ 06a095a0] Warning: not compiled with thread support, using thread emulat
ion
[swscaler @ 06a14020] deprecated pixel format used, make sure you did set range
correctly
[mpeg4 @ 06677d40] Warning: not compiled with thread support, using thread emula
tion
Output #0, avi, to 'out.avi':
  Metadata:
    ISFT            : Lavf57.62.100
    Stream #0:0(eng): Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 32x32, q=2-31,
200 kb/s, 15 fps, 15 tbn, 15 tbc (default)
    Metadata:
      creation_time   : 2017-01-21T07:17:58.000000Z
      handler_name    : Apple Alias Data Handler
      encoder         : Lavc57.72.100 mpeg4
    Side data:
      cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
Stream mapping:
  Stream #0:0 -> #0:0 (svq3 (native) -> mpeg4 (native))
Press [q] to stop, [?] for help
[svq3 @ 06a095a0] luma prediction:82
[svq3 @ 06a095a0] error while decoding MB 0 1
Error while decoding stream #0:0: Operation not permitted
frame=    0 fps=0.0 q=0.0 Lsize=       6kB time=00:00:00.00 bitrate=N/A speed=
 0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing ove
rhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters i
f used)
Conversion failed!

[Carl Eugen Hoyos]

I sent a patch that you could try to test on different samples.

[ami_stuff]

Replying to cehoyos:

I sent a patch that you could try to test on different samples.

It seems to work correctly, thanks.

[Carl Eugen Hoyos]

Pushed as 6d6faa2a2ded9cc203a9f2d8dcceebbda27a12a4 - thank you for testing!