avfoundation input device does not find attached firewire/dv source

[dave rice]

Summary of the bug:

I have a DV tape player attached to a Mac via firewire. When I open QuickTime X, I can select the DV stream as an input for QuickTime X (I'm presuming from this behavior that avfoundation is accepting the dv stream as an input); however when I query avfoundation inputs via ffmpeg it only lists screen capture and no dv input available. Is it feasible to access the dv input via the avfoundation input device?

How to reproduce:

Attach a DV tape player source to a Mac via firewire, verify that the DV is a source input to QuickTime X and other avfoundation-based apps. Quit QuickTime X. Then try to access the DV input via ffmpeg's avfoundation device.

ffmpeg -f avfoundation -list_devices 1 -i dummy
ffmpeg version 4.1.3 Copyright (c) 2000-2019 the FFmpeg developers
  built with Apple LLVM version 10.0.1 (clang-1001.0.46.4)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.3_1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --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-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  libavutil      56. 22.100 / 56. 22.100
  libavcodec     58. 35.100 / 58. 35.100
  libavformat    58. 20.100 / 58. 20.100
  libavdevice    58.  5.100 / 58.  5.100
  libavfilter     7. 40.101 /  7. 40.101
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  3.100 /  5.  3.100
  libswresample   3.  3.100 /  3.  3.100
  libpostproc    55.  3.100 / 55.  3.100
[AVFoundation input device @ 0x7fd212400380] AVFoundation video devices:
[AVFoundation input device @ 0x7fd212400380] [0] Capture screen 0
[AVFoundation input device @ 0x7fd212400380] AVFoundation audio devices:
dummy: Input/output error

[Thilo Borgmann]

Please check if your device is found after applying the attached patch to current HEAD.

[dave rice]

This is resolved in 02f65678ba9b5958cf53d1e5bc29939d941ad95f. Thanks thilo.borgmann :)