GV-HUVC を買った

http://www.iodata.jp/product/av/capture/gv-huvc/index.htm

USB 3.1 Gen1 接続で、USB Video Class 対応の HDMI キャプチャーデバイス。
専用のドライバーを必要としないので Windows 以外でも動作し、メーカーからのドライバーや専用ソフトの継続的な更新を必要としないため OS の更新などでデバイスが使えなくなる心配が薄い。
ただ USB 3.1 Gen1 が実質的に必須でAMD製チップセットなど非対応なものもあるようなので、そのあたりでトラブルが起きる可能性は少なくない。

この手の HDMI キャプチャーデバイスでは近年では AVerMedia 製のデバイスが特にメジャーだと思うが、専用のドライバーやソフトウェアがあるタイプの製品はあまり好きではないので、今回は GV-HUVC を買うことにした。
AVerMedia の UVC 対応デバイスは7月に出るらしい。

ffmpeg でフォーマットを列挙すると以下の通りで、MJPEG には非対応。

> ffmpeg -list_options true -f dshow -i video="I-O DATA GV-HUVC, Video Capture USB":audio="@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{4CFE616A-B674-474C-B539-907085A96B08}"
ffmpeg version N-91317-gb41b6b3234 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 7.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
  libavutil      56. 18.102 / 56. 18.102
  libavcodec     58. 20.102 / 58. 20.102
  libavformat    58. 17.100 / 58. 17.100
  libavdevice    58.  4.101 / 58.  4.101
  libavfilter     7. 25.100 /  7. 25.100
  libswscale      5.  2.100 /  5.  2.100
  libswresample   3.  2.100 /  3.  2.100
  libpostproc    55.  2.100 / 55.  2.100
[dshow @ 0000022f7989ac80] DirectShow video device options (from video devices)
[dshow @ 0000022f7989ac80]  Pin "繧ｭ繝｣繝励メ繝｣" (alternative pin name "0")
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1920x1080 fps=6 max s=1920x1080 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1920x1080 fps=6 max s=1920x1080 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=800x600 fps=6 max s=800x600 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=800x600 fps=6 max s=800x600 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1024x768 fps=6 max s=1024x768 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1024x768 fps=6 max s=1024x768 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1152x864 fps=6 max s=1152x864 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1152x864 fps=6 max s=1152x864 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x960 fps=6 max s=1280x960 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x960 fps=6 max s=1280x960 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x1024 fps=6 max s=1280x1024 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x1024 fps=6 max s=1280x1024 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1440x900 fps=6 max s=1440x900 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1440x900 fps=6 max s=1440x900 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1600x900 fps=6 max s=1600x900 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1600x900 fps=6 max s=1600x900 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1600x1200 fps=6 max s=1600x1200 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1600x1200 fps=6 max s=1600x1200 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1680x1050 fps=6 max s=1680x1050 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1680x1050 fps=6 max s=1680x1050 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x720 fps=6 max s=1280x720 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x720 fps=6 max s=1280x720 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=720x480 fps=6 max s=720x480 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=720x480 fps=6 max s=720x480 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=720x576 fps=6 max s=720x576 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=720x576 fps=6 max s=720x576 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x800 fps=6 max s=1280x800 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1280x800 fps=6 max s=1280x800 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1360x768 fps=6 max s=1360x768 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1360x768 fps=6 max s=1360x768 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1366x768 fps=6 max s=1366x768 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1366x768 fps=6 max s=1366x768 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=640x360 fps=6 max s=640x360 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=640x360 fps=6 max s=640x360 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=768x576 fps=6 max s=768x576 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=768x576 fps=6 max s=768x576 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=856x480 fps=6 max s=856x480 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=856x480 fps=6 max s=856x480 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=960x540 fps=6 max s=960x540 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=960x540 fps=6 max s=960x540 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1024x576 fps=6 max s=1024x576 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1024x576 fps=6 max s=1024x576 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1920x1200 fps=6 max s=1920x1200 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=1920x1200 fps=6 max s=1920x1200 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=640x480 fps=6 max s=640x480 fps=60.0002
[dshow @ 0000022f7989ac80]   pixel_format=yuyv422  min s=640x480 fps=6 max s=640x480 fps=60.0002
[dshow @ 0000022f7989ac80] DirectShow audio only device options (from audio devices)
[dshow @ 0000022f7989ac80]  Pin "Capture" (alternative pin name "Capture")
[dshow @ 0000022f7989ac80]   min ch=1 bits=8 rate= 11025 max ch=2 bits=16 rate= 44100
    Last message repeated 22 times

レイテンシーはそれなりにあるので、アクション性の高いゲームのキャプチャーなどを行う場合には HDMI スプリッターは必須だと思われる。
キャプチャーした映像には品質的な問題はない。