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How to automate video screen grabs using ffmpeg

Part 1 of this 2-part series explains how to use VLC, a GUI-based video player, to capture single still frames from a video file. If you are taking many snapshots, you may find the manual VLC method too laborious. This post shows how to automate the capture process using ffmpeg, a command-line tool. Extract frame at a given instant The first scenario is to simply take a single snapshot at a given time instant.

How to capture still frame images from a video clip

I own a point-and-shoot digital camera which also shoots movies. As a novice photographer, I struggle in taking indoor evening pictures. Finally, I resort to first making a movie with the camera, followed by capturing still frames from the movie file. This post is part 1 of a 2-part series to explain the latter. In this post, we go over how to capture, using a GUI tool, a single frame from a movie file.

Find the Fedora/Red Hat package providing a command

My previous post explains, given a Debian or Ubuntu system, how to find the package that provides a command or file. This post covers the same topic but for Fedora or any modern RPM-based system. yum provides Suppose you want to run the mate-system-log command. $ mate-system-log-bash: mate-system-log: command not found

Identify the Debian/Ubuntu package containing a command/filename

Consider this scenario: you read about this excellent Linux command that is new to you. You quickly try it out, and discover that the command is not found. Before you can install the command, you must first find the name of the package that provides it. Below, we outline the instructions to search for a package in Debian/Ubuntu. My next post will do the same for Fedora/Red Hat.

Plot bar charts using gnuplot (part 3/3)

Parts one and two of this series illustrate how to use gnuplot to plot a two-dimensional point graph with time-series data. This post, the third and final of the series, focuses on plotting a bar chart. The raw input data consists of the daily number of page views, and clicks for this blog from 2005 to 2014:

gnuplot explained (part 2/3)

Part 1 of this series presented a gnuplot script to plot the following two-dimensional graph. This post continues the discussion of the commands in the script.

How to plot 2D data using gnuplot

As the publisher of this web site, I am interested in visualizing readership growth over time. With that in mind, I set out to plot the number of page views and clicks over time. Linux is well stocked with data plotting software. This 3-part series introduces gnuplot, a command-line tool, to plot two-dimensional time-series data. Parts 1 and 2 explain how to plot a points graph; part 3, a bar chart.

Redirect local emails to a remote email account

My previous post is a guide for setting up exim4, an SMTP mail server, to use Gmail as a smarthost. One reason for setting up a mail server is to redirect my local root emails to an Internet email account that I actually monitor. In this way, I won't miss any security alert sent to the local root mailbox. This post shows you how to set up email redirection.

How to setup exim4 on Debian to use Gmail

Why bother configuring an SMTP mail server on your Linux desktop? Especially if you can send and receive all your emails within a web browser using your Gmail account, or with an email client such as Thunderbird. My reasons are twofold:

  • Some applications running on my desktop require SMTP to be set up. My desktop computer is used to stage a WordPress blog. For WordPress to send email, an SMTP server is required.
  • To redirect local root emails.

Burn DVD from an iso image

You have backed up a DVD to your hard drive in ISO format. Now, you want to burn a DVD from that image. This post illustrates how, first using the command line, then the GUI. Command Line Insert the DVD disc, and issue one of the following commands to burn a disc.

  1. growisofs To install growisofs, $ sudo apt-get update$ sudo apt-get install growisofs

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