Couldn't find ffmpeg or avconv - defaulting to ffmpeg, but may not wor

This error message usually appears when a program is trying to use either ffmpeg or avconv, which are both command-line tools for working with multimedia files, but neither of them is installed on the system.

To resolve the issue, you need to install either ffmpeg or avconv on your system. Here are the steps to install ffmpeg on Ubuntu:

1. Open a terminal window
2. Update your system's package list by running the following command:

sudo apt-get update

3. Install ffmpeg by running the following command:

sudo apt-get install ffmpeg

4. Once the installation is complete, try running the program again to see if the error message has disappeared.

If you prefer to use avconv instead of ffmpeg, you can install it using the following command:

sudo apt-get install libav-tools

After installation, you may need to modify the program's settings to use avconv instead of ffmpeg.