[FFmpeg-user] Help: is it possibile to join an image and a live stream?

[Michael Koch]

Am 07.10.2022 um 20:28 schrieb Michael Koch:
> Am 07.10.2022 um 19:32 schrieb info at mbsoft.biz:
>> i have 2 inputs
>>
>> first input image  -i logo.png
>>
>> second input dshow webcam  -f dshow -i video="my webcam"
>>
>> is it possible to show 5 seconds logo and and subsequently start webcam?
>
> it can also be done with "streamselect" filter, have a look at the 
> documentation for an example.
>

I haven't yet found a working example for sendcmd / streamselect.
What's the problem in this command line?

ffmpeg -re -f lavfi -i color=red:s=1280x720 -f lavfi -i 
testsrc2=s=1280x720 -lavfi sendcmd='5.0 streamselect map 
1';[0][1]streamselect=map=0 -f sdl2 -

The error message is "Unable to find a suitable output format for 
'streamselect' "
I'm not sure what's the meaning of this message. Does it mean
a) The previous filter has no suitable output format for the input of 
the streamselect filter
or
b) The streamselect filter has no suitable output format for the next 
filter?

The console output is below.

Michael



C:\Users\astro\Desktop\test>ffmpeg -re -f lavfi -i color=red:s=1280x720 
-f lavfi -i testsrc2=s=1280x720 -lavfi sendcmd='5.0 streamselect map 
1';[0][1]streamselect=map=0 -f sdl2 -
ffmpeg version 2022-10-02-git-5f02a261a2-essentials_build-www.gyan.dev 
Copyright (c) 2000-2022 the FFmpeg developers
   built with gcc 12.1.0 (Rev2, Built by MSYS2 project)
   configuration: --enable-gpl --enable-version3 --enable-static 
--disable-w32threads --disable-autodetect --enable-fontconfig 
--enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp 
--enable-bzlib --enable-lzma --enable-zlib --enable-libsrt 
--enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 
--enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid 
--enable-libaom --enable-libopenjpeg --enable-libvpx 
--enable-mediafoundation --enable-libass --enable-libfreetype 
--enable-libfribidi --enable-libvidstab --enable-libvmaf 
--enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid 
--enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va 
--enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt 
--enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora 
--enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb 
--enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
   libavutil      57. 38.100 / 57. 38.100
   libavcodec     59. 49.100 / 59. 49.100
   libavformat    59. 33.100 / 59. 33.100
   libavdevice    59.  8.101 / 59.  8.101
   libavfilter     8. 49.100 /  8. 49.100
   libswscale      6.  8.112 /  6.  8.112
   libswresample   4.  9.100 /  4.  9.100
   libpostproc    56.  7.100 / 56.  7.100
Input #0, lavfi, from 'color=red:s=1280x720':
   Duration: N/A, start: 0.000000, bitrate: N/A
   Stream #0:0: Video: wrapped_avframe, yuv420p, 1280x720 [SAR 1:1 DAR 
16:9], 25 fps, 25 tbr, 25 tbn
Input #1, lavfi, from 'testsrc2=s=1280x720':
   Duration: N/A, start: 0.000000, bitrate: N/A
   Stream #1:0: Video: wrapped_avframe, yuv420p, 1280x720 [SAR 1:1 DAR 
16:9], 25 fps, 25 tbr, 25 tbn
[NULL @ 0000023291ccd4c0] Unable to find a suitable output format for 
'streamselect'
streamselect: Invalid argument