FFmpeg video overlay

Question

I am trying to overlay an input video with many images where each image should be shown for a short time. I achieved this using complex filter (the command below). The problem is that I have many, many images (>1000) :-)

ffmpeg -y -i in.mp4 

-i logo1.png 
-i logo2.png 
-i logo3.png 

-filter_complex "

[0:v][1:v] overlay=10:10:enable='between(n,2,4)'    [tmp]; 
[tmp][2:v] overlay=30:30:enable='between(n,6,8)'    [tmp]; 
[tmp][3:v] overlay=50:50:enable='between(n,10,12)'; 

" out.mp4 

Does FFmpeg allows a user to pass this data over a text-file ? The images are generated in memory, so pipes are also fine (in fact preferred).

(if that is not possible can I pass raw generated video in Bgra format ?; but I would not prefer this because the blend operation is more expensive + more IO: has to be as fast as possible)

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Edit: If I use the following configuration, only the last sent image is overlayed.

-i ski.mp4 
-f image2pipe -vcodec png -i -

-filter_complex "[0:v][1:v] overlay=10:10:enable='between(n,2,3)' [tmp]; 
                 [tmp][1:v] overlay=30:30:enable='between(n,6,7)'"

-f mp4", "out.mp4"

FFmpeg outputs (it seems that it skips images if they have different sizes):

 Input stream #1:0 frame changed from size:1417x665 fmt:rgba to size:1800x700 fmt:rgba
 Input stream #1:0 frame changed from size:1800x700 fmt:rgba to size:550x371 fmt:rgba
 Input stream #1:0 frame changed from size:550x371 fmt:rgba to size:256x256 fmt:rgba

How can I instruct FFmpeg that for the first filter uses 1st image, for the second 2nd image in pipe, etc. (the images have different sizes) ?

Answer 1

If you can input your images as a sequence and specify your overlay x, y and time qualifiers as an expression, then this can be made as a manageable command.

You can input the images via pipe using the -f image2pipe -vcodec png as an input option.

Also, FFmpeg can reference a filterchain from a script

-filter_complex_script filename (global)

This option is similar to -filter_complex, the only difference is that its argument is the name of the file from which a complex filtergraph description is to be read.