videoGrabberExample doesn't work

Hi.

I’m trying to run videoGrabberExample, but get the error like this

2020-08-17 18:38:09.010198+0900 videoGrabberExampleDebug[1174:16462] Metal API Validation Enabled
2020-08-17 18:38:09.548978+0900 videoGrabberExampleDebug[1174:16462] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x600000253420> F8BB1C28-BAE8-11D6-9C31-00039315CD46
2020-08-17 18:38:09.601331+0900 videoGrabberExampleDebug[1174:16462]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
2020-08-17 18:38:09.601761+0900 videoGrabberExampleDebug[1174:16462]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
2020-08-17 18:38:09.631710+0900 videoGrabberExampleDebug[1174:16462] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x60000025ec80> 30010C1C-93BF-11D8-8B5B-000A95AF9C6A
[notice ] Device: 0: FaceTime HD Camera
[notice ] 0: FaceTime HD Camera
[warning] ofAvFoundationGrabber:  requested width and height aren't supported. Setting capture size to closest match: 1280 by 720

[ error ] ofAvFoundationGrabber:  could not set framerate to: 60. Device supports: 
[ error ]   framerate range of: 1 to 30
(lldb) 

then I set the framerate to 30, but I get this error

2020-08-17 18:43:00.709115+0900 videoGrabberExampleDebug[1225:20377] Metal API Validation Enabled
2020-08-17 18:43:01.279817+0900 videoGrabberExampleDebug[1225:20377] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x600000258120> F8BB1C28-BAE8-11D6-9C31-00039315CD46
2020-08-17 18:43:01.334028+0900 videoGrabberExampleDebug[1225:20377]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
2020-08-17 18:43:01.334529+0900 videoGrabberExampleDebug[1225:20377]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
2020-08-17 18:43:01.364347+0900 videoGrabberExampleDebug[1225:20377] [plugin] AddInstanceForFactory: No factory registered for id <CFUUID 0x60000023ad80> 30010C1C-93BF-11D8-8B5B-000A95AF9C6A
[notice ] Device: 0: FaceTime HD Camera
[notice ] 0: FaceTime HD Camera
[warning] ofAvFoundationGrabber:  requested width and height aren't supported. Setting capture size to closest match: 1280 by 720

(lldb) 

and get this window

I think this error comes from FaceTime HD Camera’s setting, but I can’t figure out what should I do.
I use macbook pro (macOS Catalina 10.15.6), Xcode(11.6).

I’d like to ask you for your help.Thanks.

Face Time HD camera of Mac Book Pro seems to support only 1280 × 720p.

input

ffmpeg -f avfoundation -i "0" out.mpg

output

ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 11.0.3 (clang-1103.0.32.62)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
[avfoundation @ 0x7fead100a200] Selected framerate (29.970030) is not supported by the device.
[avfoundation @ 0x7fead100a200] Supported modes:
[avfoundation @ 0x7fead100a200]   1280x720@[1.000000 30.000000]fps
    Last message repeated 2 times
0: Input/output error