I need to horizontally flip my webcam image for a meeting. I tried the instructions in this site https://wiki.archlinux.org/index.php/Webcam_setup#Applications</Webcam setup> which uses v4l2 and v4l2loopback to generate a virtual camera.
# modprobe v4l2loopback
Check the name of the newly created camera:
$ v4l2-ctl --list-devices
Dummy video device (0x0000) (platform:v4l2loopback-000):
/dev/video1
Then you can run ffmpeg to read from your actual webcam (here /dev/video0) and invert it and feed it to the virtual camera:
$ ffmpeg -f v4l2 -i /dev/video0 -vf "vflip" -f v4l2 /dev/video1
You can use the "Dummy" camera in your applications instead of the "Integrated" camera.
With these settings I was successful in vertically flipping my video. But that is not what I want. I want it to be flipped horizontally.
So I tried this:
$ ffmpeg -f v4l2 -i /dev/video0 -vf **"hflip"** -f v4l2 /dev/video1
But I then I get no image from my cam.
What am I doing wrong?
I'm using Fedora 31 in a desktop.
COMPLETE LOG:
ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 9 (GCC)
configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection' --extra-ldflags='-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld ' --extra-cflags=' ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libaom --enable-libdav1d --enable-libass --enable-libbluray --enable-libcdio --enable-libdrm --enable-libjack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librsvg --enable-libsrt --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzimg --enable-libzvbi --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-libmfx --enable-runtime-cpudetect
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 233168.222502, bitrate: 147456 kb/s
Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo (native) -> rawvideo (native))
Press [q] to stop, [?] for help
Output #0, video4linux2,v4l2, to '/dev/video2':
Metadata:
encoder : Lavf58.29.100
Stream #0:0: Video: rawvideo (Y42B / 0x42323459), yuv422p, 640x480, q=2-31, 147456 kb/s, 30 fps, 30 tbn, 30 tbc
Metadata:
encoder : Lavc58.54.100 rawvideo
frame= 31 fps=0.0 q=-0.0 size=N/A time=00:00:01.03 bitrate=N/A dup=16 drop=0 sframe= 46 fps= 46 q=-0.0 size=N/A time=00:00:01.53 bitrate=N/A dup=16 drop=0 sframe= 61 fps= 40 q=-0.0 size=N/A time=00:00:02.03 bitrate=N/A .....
