How to create a 5 second video from one image in ffmpeg?

Question

fmpeg

How to make a 5 second video from one image? There is a command: ffmpeg -framerate 1/5 -i img.png -c:v libx264 -r 30 -pix_fmt yuv420p out.mp4 but here the duration can only be changed by the -r parameter, i.e. the number of frames, but then I can’t convert it later I will stream this video to mpg that if I set the -r 1/5 parameter, then the duration is 5 seconds and the number of frames per second turns out to be such that ffmpeg cannot convert this video to mpg if I set the -r 1 parameter, then it is converted
2. And another question is how to merge two mp4 videos in ffmpeg? concat:"video1|video2" only glues mpg, the concat filter gives out exceptions that are not understandable, forwarded all the commands that are on the Internet on different forums, they all give errors. Then [out] strem.. then [a] strem.. xt then there filter no such: [0:v]/ Who dealt with this garbage please help

Answer 1

video generation:
mp4 gluing:
convert in a couple of seconds to .ts
glue .ts and convert to mp4:

ffmpeg -i "concat:in1.ts|in2.ts|in3.ts|in4.ts" -c copy -bsf aac_adtstoasc out.mp4

Answer 2

Here is
ffmpeg -filter_complex aevalsrc=0 -loop 1 -i black.png -t 5 out.mp4
doesn't work.
The video is generated, but in place of the picture.png the background is gray.
Tell me how to fix