[FFmpeg-user] Can't stop recording

[Elliott Balsley]

I'm trying to capture a stream from a webcam, and it says "press [q] to
stop, [?] for help".  But neither of those keys has any effect.  The only
way I can get it to stop is by pressing ctrl-C repeatedly, and then it
gives an error and the output file is not playable.  I'm running ffmpeg in
Terminal in OS X 10.10.5.  The webcam is a Logitech c920.

$ ffmpeg -f avfoundation -video_size 1920x1080 -framerate 30 -pixel_format
uyvy422 -i "0" -vcodec libx264 -pix_fmt yuv420p test.mov
ffmpeg version 3.0.git Copyright (c) 2000-2016 the FFmpeg developers
  built with Apple LLVM version 7.0.2 (clang-700.1.81)
  configuration: --prefix=/opt/local --enable-swscale --enable-avfilter
--enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus
--enable-libtheora --enable-libschroedinger --enable-libopenjpeg
--enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex
--enable-libass --enable-libbluray --enable-lzma --enable-gnutls
--enable-fontconfig --enable-libfreetype --enable-libfribidi
--disable-indev=jack --disable-outdev=xv --mandir=/opt/local/share/man
--enable-shared --enable-pthreads --cc=/usr/bin/cc --enable-vda
--enable-audiotoolbox --enable-videotoolbox --arch=x86_64 --enable-yasm
--enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
--enable-nonfree --enable-libfdk-aac --enable-libfaac
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 42.100 / 57. 42.100
  libavformat    57. 36.100 / 57. 36.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 45.100 /  6. 45.100
  libavresample   3.  0.  0 /  3.  0.  0
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
[avfoundation @ 0x7f95e200da00] Stream #0: not enough frames to estimate
rate; consider increasing probesize
Input #0, avfoundation, from '0':
  Duration: N/A, start: 24544.717833, bitrate: N/A
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1920x1080,
1000k tbr, 1000k tbn
File 'test.mov' already exists. Overwrite ? [y/N] y
[mov @ 0x7f95e5801600] Frame rate very high for a muxer not efficiently
supporting it.
Please consider specifying a lower framerate, a different muxer or -vsync 2
[libx264 @ 0x7f95e5805c00] MB rate (8160000000) > level limit (2073600)
[libx264 @ 0x7f95e5805c00] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2
[libx264 @ 0x7f95e5805c00] profile High, level 5.2
[libx264 @ 0x7f95e5805c00] 264 - core 148 - H.264/MPEG-4 AVC codec -
Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1
ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00
mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11
fast_pskip=1 chroma_qp_offset=-2 threads=34 lookahead_threads=5
sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0
constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1
weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40
intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0
qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[mov @ 0x7f95e5801600] Using AVStream.codec to pass codec parameters to
muxers is deprecated, use AVStream.codecpar instead.
[mov @ 0x7f95e5801600] WARNING codec timebase is very high. If duration is
too long,
file may not be playable by quicktime. Specify a shorter timebase
or choose different container.
Output #0, mov, to 'test.mov':
  Metadata:
    encoder         : Lavf57.36.100
    Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p, 1920x1080,
q=2-31, 1000k fps, 1000k tbn
    Metadata:
      encoder         : Lavc57.42.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
Press [q] to stop, [?] for help
^Cav_interleaved_write_frame(): Immediate exit requested
^CReceived > 3 system signals, hard exiting
$