[FFmpeg-user] Insert black frames -- How?

[Mark Filipak (ffmpeg)]

On 02/08/2021 08:24 PM, Carl Zwanzig wrote:
> On 2/8/2021 5:10 PM, Mark Filipak (ffmpeg) wrote:
>> I want to insert black frames into a stream on a regular basis.
>> #1, Is that an input device? I think so. Or,
> 
> I think what you want is based on "-f lavfi color=c=black" although it will depend on whether you 
> want to insert the black frame between existing frames or on top of one of them (whether to just 
> periodically overlay or to create segments).

That's what I was just looking at.
As a 1st step to get a source (based on the pink example in the docs), I tried this:
C:\AVOut\THE LAST EMPEROR>ffmpeg -f lavfi -graph "color=c=pink [out0]" test.mkv
ffmpeg started on 2021-02-08 at 20:21:13
Report written to "ffmpeg-20210208-202113.log"
Log level: 32
ffmpeg version N-100851-g9f38fac053 Copyright (c) 2000-2021 the FFmpeg developers
   built with gcc 9.3-win32 (GCC) 20200320
   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-zlib --enable-libxml2 
--enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig 
--enable-opencl --enable-libvmaf --enable-vulkan --enable-libvorbis --enable-amf --enable-libaom 
--enable-avisynth --enable-libdav1d --enable-libdavs2 --enable-ffnvcodec --enable-cuda-llvm 
--enable-libglslang --enable-libass --enable-libbluray --enable-libmp3lame --enable-libopus 
--enable-libtheora --enable-libvpx --enable-libwebp --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 --enable-libvidstab --enable-libx264 --enable-libx265 
--enable-libxavs2 --enable-libxvid --enable-libzimg --extra-cflags=-DLIBTWOLAME_STATIC 
--extra-cxxflags= --extra-ldflags=-pthread --extra-libs=-lgomp
   libavutil      56. 64.100 / 56. 64.100
   libavcodec     58.119.100 / 58.119.100
   libavformat    58. 65.101 / 58. 65.101
   libavdevice    58. 11.103 / 58. 11.103
   libavfilter     7.100.100 /  7.100.100
   libswscale      5.  8.100 /  5.  8.100
   libswresample   3.  8.100 /  3.  8.100
   libpostproc    55.  8.100 / 55.  8.100
[NULL @ 0000016b7a3a9000] Requested output format 'lavfi' is not a suitable output format
test.mkv: Invalid argument

> see also 
> https://ffmpeg.org/ffmpeg-filters.html#allrgb_002c-allyuv_002c-color_002c-haldclutsrc_002c-nullsrc_002c-pal75bars_002c-pal100bars_002c-rgbtestsrc_002c-smptebars_002c-smptehdbars_002c-testsrc_002c-testsrc2_002c-yuvtestsrc 

I'll take a look at it. Thanks, Carl!