[FFmpeg-user] Replace part of video with series of images

[Joshua Grauman]

I've made some progress with my command. But I've run into a problem. In 
the docs, under the drawbox command, it lists an option 'replace'

replace
Applicable if the input has alpha. With value 1, the pixels of the painted 
box will overwrite the video’s color and alpha pixels. Default is 0, which 
composites the box onto the input, leaving the video’s alpha intact.

This is exactly what I need. But I can't get it to work. Whenever I do a 
command with it, I get:

"[Parsed_drawbox_0 @ 0x564929e46aa0] Option 'replace' not found
[AVFilterGraph @ 0x564929e44bc0] Error initializing filter 'drawbox' with 
args 'enable=between(t,2,3):color=0x000000FF:t=999:replace=1'"

I tried to upgrade my ffmpeg to the latest version. I have ffmpeg version 
3.4.1-1~16.04.york0 Copyright (c) 2000-2017 the FFmpeg developers

Does anyone know what I'm doing wrong to get the replace option to work on 
drawbox?

Here is my full command:

ffmpeg -i screencast.avi -ss -2 -i output.avi -filter_complex 
"[0:v]drawbox=enable='between(t,2,3)':color=0x000000FF:t=999:replace=1[out]; 
[out][1:v]overlay=0:0:enable='between(t,2,3)':format=rgb[out2]" -strict 
experimental -map [out2] output.avi

Thanks!

Josh

> Hi all,
>
> Would someone mind helping me to get a commandline correct?
>
> I have a video, screencast.avi, of utvideo with transparency.
>
> I extract a couple seconds of images from screencast.avi like:
>
> ffmpeg -ss 31 -t 2 -i screencast.avi filename%03d.png
>
> I would like to edit the images and then "put them back" into the video, 
> replacing the appropriate frames.
>
> I know how to use the overlay filter, but don't know how to make it use the 
> whole series of images at the correct time. Plus, I can't simply overlay the 
> video as it has transparency. I would need to replace the frames, or blank 
> the appropriate frames before overlaying.
>
> Thanks for help getting the command correct!
>
> Josh
>
> Here are my attempts for anyone interested:
>
> This command uses all the images, but doesn't start and end them at the right 
> place:
>
> ffmpeg -i screencast.avi -pattern_type glob -i "filename*.png" 
> -filter_complex overlay output.avi
>
> This command puts the overlay in the correct frames, but only uses a single 
> .png file, not all of them:
>
> ffmpeg -i screencast.avi -pattern_type glob -i "filename*.png" 
> -filter_complex "overlay=0:0:enable='between(t,2,3)'" output.avi
>
> Plus, both commands incorrectly overlay the transparent images, rather than 
> replacing the frames.
>
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