I know how to chroma key / greenscreen filter a background of a video stream and replace it by an image using v4l2loopback. After running
$ sudo modprobe v4l2loopback
my code is as follows:
$ ffmpeg -i background.jpg -f v4l2 -pix_fmt mjpeg \
-framerate 30 -video_size 1280x720 -i /dev/video0 \
-filter_complex \
"[0:v]scale=1280x720[bg]; \
[1:v]colorkey=0x00b140:0.5:0.0[ckout];
[bg][ckout]overlay" \
-pix_fmt yuv420p -f v4l2 /dev/video1
Then I can simply choose at whatever video-playing-app I like, the new pseudo webcam as input.
Instead of a still image, I would like to have a short video, looping continuously in the background. I am pretty sure that this is possible, but have no idea how, any hints are greatly appreciated!
Update 1: As requested, here is the full log of the command as suggested in the response
$ ffmpeg -stream_loop 5 -re -i some_gif.gif \
-f v4l2 -pix_fmt mjpeg -framerate 30 \
-video_size 1280x720 -i /dev/video0 \
-filter_complex \
"[0:v]scale=1280x720[bg]; \
[1:v]colorkey=0x61A051:0.3:0.0[ckout]; \
[bg][ckout]overlay" \
-pix_fmt yuv420p -f v4l2 /dev/video1
ffmpeg version 3.4.8-0ubuntu0.2 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
libavutil 55. 78.100 / 55. 78.100
libavcodec 57.107.100 / 57.107.100
libavformat 57. 83.100 / 57. 83.100
libavdevice 57. 10.100 / 57. 10.100
libavfilter 6.107.100 / 6.107.100
libavresample 3. 7. 0 / 3. 7. 0
libswscale 4. 8.100 / 4. 8.100
libswresample 2. 9.100 / 2. 9.100
libpostproc 54. 7.100 / 54. 7.100
Input #0, gif, from 'some_gif.gif':
Duration: N/A, bitrate: N/A
Stream #0:0: Video: gif, bgra, 640x640, 10 fps, 10 tbr, 100 tbn, 100 tbc
Input #1, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 433330.420280, bitrate: N/A
Stream #1:0: Video: mjpeg, yuvj422p(pc, bt470bg/unknown/unknown), 1280x720, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
Stream mapping:
Stream #0:0 (gif) -> scale
Stream #1:0 (mjpeg) -> colorkey
overlay -> Stream #0:0 (rawvideo)
Press [q] to stop, [?] for help
[swscaler @ 0x563d17c69e80] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0x563d17c69e80] No accelerated colorspace conversion found from yuv422p to argb.
Output #0, v4l2, to '/dev/video1':
Metadata:
encoder : Lavf57.83.100
Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1280x720, q=2-31, 110592 kb/s, 10 fps, 10 tbn, 10 tbc (default)
Metadata:
encoder : Lavc57.107.100 rawvideo
Past duration 0.899986 too largeN/A time=00:00:05.10 bitrate=N/A speed= 1x
frame= 98 fps= 10 q=-0.0 Lsize=N/A time=00:00:09.80 bitrate=N/A dup=0 drop=20 speed=1.03x
video:132300kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Update 2: After applying an update via
$ sudo add-apt-repository ppa:jonathonf/ffmpeg-4
$ sudo apt-get update
$ sudo apt-get install ffmpeg
I now have the following version installed
ffmpeg version 4.3.1-0york0~18.04 Copyright (c) 2000-2020 the FFmpeg developers
And now the answer works :)
Use -stream_loop to loop and -re for real-time speed since you're streaming (or else it will play super fast):
$ ffmpeg -stream_loop -1 -re -i input.mp4 -f v4l2 -pixel_format mjpeg \
-framerate 30 -video_size 1280x720 -i /dev/video0 \
-filter_complex \
"[0:v]scale=1280x720[bg]; \
[1:v]colorkey=0x00b140:0.5:0.0[ckout];
[bg][ckout]overlay,format=yuv420p" \
-f v4l2 /dev/video1
Given that your inputs are YUV consider replacing colorkey (RGB) with chromakey (YUV).