ffmpeg input from images stream out video

Question

I am using ffmpeg to capture a video recording device and would like to add an overlay to it .

I have images being rendered on the fly and I would like to use them as the overlay .

How can I take a set of Images as they are being rendered and use it as an overlay to a video stream ?

Answer 1

Couldn't wait! Figured it out:

I saved an image to the file out.png at a fixed frame rate from processing.

Created a fifo:

mkfifo fifo

Then in one terminal:

tail -f out.png  > fifo

Then in another terminal:

cat fifo | ffmpeg  -f image2pipe -r 1 -i pipe:0 spo.mp4

Making sure to close tail first allowing ffmpeg to write the last bit of the file.