ffmpeg part two - Electric Boogaloo

I just attended the Watkins Glen opening day for the second year. It was, again, a blast. I made some slight adjustments to my ffmpeg assembly procedure from last year. Dashcam saves video in 5-minute chunks Instead of creating .list files, I simply used a pipe as input: for fo in AMBA091*; do echo file "$fo"; done \ | ffmpeg -f concat -i - -c copy Front-Track1.mov Front and Rear videos need to be combined Much like last year, I made short samples to confirm if any offsets needed to be done.

Intel GPU Scaling mode

I was attempting to run my laptop at a lower resolution than the laptop panel. However, by default the video is scaled to fill the panel. This causes the image to be distorted (fonts look bad, etc). On Linux (with Xorg, anyway), this behaviour can be tweaked with xrandr: $ xrandr --output LVDS1 --set "scaling mode" "Center" This is not a persistent setting, which is fine for my purposes.

My failed experiment with CalDAV/CardDAV

In an ongoing quest to attempt to lessen my Google dependancy, I decided to self-host my Calendar and Contacts using Baïkal. Installing and configuring Baïkal is sufficiently documented elsewhere. This post is a 9somewhat short) account of why I’m giving up on self-hosted contacts and calendars. Google The problems can be summed up into these bullet points: It is assumed (and practically required) to use Google Play Store Google Play Store requires a Google Account Google Account means you have Mail, Calendar, and Contacts Simply adding your google account into your phone causes Mail, Calendar and Contacts to sync.

AWStats from multiple hosts

I decided I wanted some stats. There are a few options: Use a service (Google Analytics, etc) or parse your logs. Both have pros and cons. This article isn’t supposed to help you decide. I just wanted simple stats based on logs: It’s non-intrusive to visitors, doesn’t send their browsing habits to third parties (other than what they send themselves), and uses the apache log data I’ve already got for the entire year.

Discard (TRIM) with KVM Virtual Machines

Update - March 09 2020 Since writing this article, I’ve made a few observations: More people read this than expected QEMU has since added discard support to the standard virtio disk, avoiding the need to use virtio-scsi It kinda sorta works out of the box. I’ve written a brief followup: Discard (TRIM) with KVM Virtual Machines… in 2020! Original Article I’ve got a bunch of KVM virtual machines running at home.

Multiple Instances of Gnome Terminal

Gnome 3 introduced a very handy feature, grouping multiple application windows (whether they be separate instances or not) into a single desktop icon. This means when <alt+Tab>ing through your windows, you can skip over the dozen firefox windows, then dive into just your terminal windows. Generally, this works great, and I think most users don’t have any issues. However, some people (myself included) use a lot of terminals. Some are temporary short-lived generic terminals.

Video assembly with ffmpeg

I recently took my car to a racetrack, covered with cameras. I wanted to post these on youtube, but encountered a few issues: Dashcam saves video in 5-minute chunks Front and Rear videos need to be combined I don’t know anything about video editing I didn’t have a working video editor Fedora doesn’t seem to ship ffmpeg, and rpmfusion doesn’t support Fedora 22 yet

Living with BTRFS

This is the contents of a presentation I gave to KWLug in April 2015, roughly converted to blog format. The slides are available. I’ll update this post with a link to the kwlug.org podcast when it goes online. Audio and Video available via kwlug.org. I didn’t get through all of the points, I barely touched on snapshots (and didn’t cover any utilities). I’ll post a follow-up with my filesystem corruption demonstration instructions.

Adding a dependency into upstream-supplied systemd units

I recently restarted all my VMs at once and found that several managed to start services before they finished mounting their NFS shares. These shares back apache virtualhosts, mysql databases, and ultimately left several services in non-functional states. Systemd has the ability to depend on services (Requires=, and others) as well as filesystems (RequiresMountsFor=). However, I don’t want to modify or replace the .service files installed from the package. I’d have to manually reconcile changes during updates, and it just generally isn’t nice.

Recovering a deleted file (on btrfs)

So you might find yourself saying this one day: HELP! I just deleted a file on my btrfs! It wasn’t old enough to be in a backup, snapshot, or git It was old enough that I don’t want to retype it. How do I get it back? Also, my btrfs is on an SSD, and it might kick off a garbage collection routine at any time! Well, as luck would have it, I just did that to a blog post I’ve spent all evening writing.