初次接触ffmpeg时，在macOS上没问题，在Ubuntu上也没问题，但是在Windows上就出现了：
错误：
[dshow @ 00000238d5075880] DirectShow video devices (some may be both video and audio devices) [dshow @ 00000238d5075880] Could not enumerate video devices (or none found). [dshow @ 00000238d5075880] DirectShow audio devices [dshow @ 00000238d5075880] Could not enumerate audio only devices (or none found).
E:\ffmpeg学习>ffmpeg -list_devices true -f dshow -i dummy ffmpeg version n4.4-80-gbf87bdd3f6-20210828 Copyright (c) 2000-2021 the FFmpeg developers built with gcc 10-win32 (GCC) 20210408 configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libdrm --disable-vaapi --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra-version=20210828 libavutil 56. 70.100 / 56. 70.100 libavcodec 58.134.100 / 58.134.100 libavformat 58. 76.100 / 58. 76.100 libavdevice 58. 13.100 / 58. 13.100 libavfilter 7.110.100 / 7.110.100 libswscale 5. 9.100 / 5. 9.100 libswresample 3. 9.100 / 3. 9.100 libpostproc 55. 9.100 / 55. 9.100 [dshow @ 00000238d5075880] DirectShow video devices (some may be both video and audio devices) [dshow @ 00000238d5075880] Could not enumerate video devices (or none found). [dshow @ 00000238d5075880] DirectShow audio devices [dshow @ 00000238d5075880] Could not enumerate audio only devices (or none found). dummy: Immediate exit requested
解决办法
在官方下载screen capture recorder：
screen capture recorder官方下载：
https://github.com/rdp/screen-capture-recorder-to-video-windows-free/releases
Windows下安装exe时直接默认安装即可。
再次查看，可以看到已经出现了
E:\ffmpeg学习>ffmpeg -list_devices true -f dshow -i dummy ffmpeg version n4.4-80-gbf87bdd3f6-20210828 Copyright (c) 2000-2021 the FFmpeg developers built with gcc 10-win32 (GCC) 20210408 configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --enable-libvmaf --enable-vulkan --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable-avisynth --enable-libdav1d --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libglslang --enable-libgme --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libdrm --disable-vaapi --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra-version=20210828 libavutil 56. 70.100 / 56. 70.100 libavcodec 58.134.100 / 58.134.100 libavformat 58. 76.100 / 58. 76.100 libavdevice 58. 13.100 / 58. 13.100 libavfilter 7.110.100 / 7.110.100 libswscale 5. 9.100 / 5. 9.100 libswresample 3. 9.100 / 3. 9.100 libpostproc 55. 9.100 / 55. 9.100 [dshow @ 000001575d485880] DirectShow video devices (some may be both video and audio devices) [dshow @ 000001575d485880] "screen-capture-recorder" [dshow @ 000001575d485880] Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{4EA69364-2C8A-4AE6-A561-56E4B5044439}" [dshow @ 000001575d485880] DirectShow audio devices [dshow @ 000001575d485880] "virtual-audio-capturer" [dshow @ 000001575d485880] Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{8E146464-DB61-4309-AFA1-3578E927E935}" dummy: Immediate exit requested E:\ffmpeg学习>
然后就可以自由自在的玩耍了：
#录制 ffmpeg -f dshow -i video="screen-capture-recorder" -r 30 out.yuv #播放 ffplay -pix_fmt bgr0 -s 2194x1234 out.yuv
