Picture in picture (pip) video with ffmpeg
The following command line worked on Ubuntu 13.10. However it does not work with the avconv/ffmpeg shipped with Ubuntu. Instead a static build was used from this site:
http://ffmpeg.gusari.org/static/
~/bin/ffmpeg -i inlay.mkv -i background.mp4 -filter_complex "[0]scale=iw/5:ih/5 [pip]; [1][pip] overlay=main_w-overlay_w-10:main_h-overlay_h-10" PIP_video.mp4
This part:
[0]scale=iw/5:ih/5
...seems to control the size of the inlay, so a bigger divisor yields a smaller inlay. It may be that the [pip] follwing the part, tags file 0 as a pip thingy.
This part:
overlay=main_w-overlay_w-10:main_h-overlay_h-10
...seems to control where the inlay is placed, with coordinates being x,y with origo in the top left of the background (main) video. "main_w", "main_h", "overlay_w" and "overlay_h" seems to be variables available denoting the width and height of each video.
It may be that the "[1][pip]" preceding it first refers to the background video (being indexed as 1, that is the second video in a 0-based system), and the the "[pip]" somehow carries over from the preceding part and then references the video there. "pip" may have some pippy meaning or it is just a tag.
In a recent time I had a task to make a picture in picture effect of two videos using ffmpeg.In this blog I am going to share the details of how to make a PIP effect using ffmpeg and also configuring some of its factors.