Machine learning algorithms for video processing typically work on frames (images) rather than video. In a typical use-case, FFmpeg can be used to extract images from video – in this example, a 50-frame sequence starting at 1:47: Omit the -vf…
Category: Linux Server
FFmpeg lossless filtering
Preserving Data Running a simple FFmpeg filter command: … one might expect the output video to be the same as the input video. Note that both input and output videos use the same container format (file name extension), and the…
https and the browser conspiracy
While Google promotes HTTPS Everywhere, browsers have been working with a certifying authority oligopoly for many years promoting and enforcing an industry based on perception. https: The good and the bad The ‘s’ in https stands for ‘secure’ and indicates…
HTTP DDoS: “Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)”
Our servers were attacked recently by a constant stream of HTTP POST requests. The requests were coming in from a large range of IP addresses, at a rate of about 5-10 per second, with random POST data. However, all the…
Virtualmin + SFTP + chroot
This guide examines setting up chroot’ed SFTP-only user accounts under Virtualmin. The Rationale: SFTP is a secure alternative to FTP and FTPS that uses SSH. With this setup, no FTP server is needed, as the native sshd server is used…
Linux memory leak detection
Tracking down the source of a memory leak in Linux is not always straightforward… Signs of a Memory Leak: Typically, the first sign of a memory leak is the oom-killer. If programs start dying inexplicably, check the system log (usually…
Compiling programs in Fedora
Say you want to install a program in Fedora… Before Compiling: Many programs are available easily in the Fedora repositories via yum. If you don’t already have a graphical package management tool, then install PackageKit or yumex. If you prefer…