Hang Out With J. B. Rainsberger

Byobu Session Name in Terminal Window Title

Tue, 17 Mar 2026 00:00:00 +0000

I started using multiple byobu windows to organize my projects, but in the process, something annoying happened: I began to lose track of which window was which. When switching windows, I couldn’t tell from the window title which byobu window to switch to.

“Uhh… which one?”

Fortunately, I use tmux as the terminal back-end for byobu, so I some very elementary tmux configuration was enable to solve the problem.

Turn Titles On in `tmux`

In a tmux window:

Press F12.
Type :set -g set-titles on.
Type :set -g set-titles-string "#{session_name} @ #{host_short}:#{pane_current_path}".

When you reopen the terminal window, you’ll see that the byobu session name is now at the beginning of the terminal window title, making it easier to see when switching windows.

“A little busy, but good enough for now.”

Remember These Settings Forever

Edit the .tmux.conf configuration file. I found mine at $HOME/.config/byobu/.tmux.conf. Add these lines:

set -g set-titles on
set -g set-titles-string "#{session_name} @ #{host_short}:#{pane_current_path}"

When you reopen the terminal window, you’ll see that these settings have become yours to keep forever.

Viewing HEIC (HEIF) Images on Pop! OS 22.04

Tue, 14 Oct 2025 00:00:00 +0000

Today I was blindsided by the existence of HEIC images, because I don’t often receive images from iPhone/iPad users. Since Pop!_OS is still running Ubuntu 22.04, I not only didn’t have the library I needed to view these images, but when I found the library I needed, the standard package manager had an out-of-date version for the images I was trying to view. It took an hour of stumbling around to track down a solution.

The Solution

Install the latest version of the libheif package from the Ubuntu PPA.

$ sudo add-apt-repository ppa:strukturag/libheif
$ sudo nala install libheif1 heif-gdk-pixbuf heif-thumbnailer

The Symptom

I couldn’t open the HEIC images using eog, but I could open them using GIMP. I wanted to convert the images in bulk to JPG, so I didn’t stop at using GIMP to convert the images one by one using the UI.

Attempt 1

I tried to install heif-gdk-pixbuf, but then neither magick nor eog could read the image. I got this error message:

Could not read HEIF/AVIF file: Invalid input: Unspecified: Metadata not correctly assigned to image

This is how I learned that the version (1.12) of libheif that ships (as of the date of writing this) in the Ubuntu package manager can’t read HEIC images taken on iOS 18. I needed to install the latest version (1.19.8) from the Ubuntu PPA listed in the solution.

Now I can receive images from my friends who use iOS 18 and, so far, all the image tools I use can read the images without issue.

Video Gradually and Increasingly Falling Behind: Don't Use Buffering

Wed, 16 Jul 2025 00:00:00 +0000

I noticed in early 2025 that, when I used my USB external webcam together with OBS Studio for video sessions, that the video signal was falling gradually and increasingly behind my audio signal and, indeed, real time. Sometimes it took 10 minutes, sometimes it took an hour, but eventually, my video would become so far out of sync with my audio that it became too distracting to continue. Restarting OBS Studio brought the camera back in sync with my microphone.

The problem lay in buffering, so I turned it off, and now all seems well.

In OBS Studio, open the Properties for your V4L2 Video Source.
Look for the option Use buffering and unselect it. In OBS Studio 31, this is a checkbox, so uncheck it.

I don’t know whether you need to restart OBS Studio for this change to take effect, but you might.

With buffering off, my webcam has not (yet) fallen behind noticeably, even after over 90 minutes of continuous use on my laptop. If the symptom remains, it is much much much less noticeable.

A Fix?

The nice folks in the OBS Studio community are working on a fix as of July 25, 2025.

Key References

Some Details

First, the ingredients that led to the symptom:

OBS Studio 31.0.4 running on Flatpak
Anker PowerConf C200 external USB webcam connected by USB-A
Røde lapel microphone connected to an audio-to-USB adapter connected to an external (powered) USB hub connected by USB-A
The Zoom client for Linux
Pop!_OS 22.04

The symptom: the video signal echoed through OBS Studio and transmitted over Zoom gradually and increasingly fell behind real time, although my audio signal stayed very close (close enough!) to real time for me not to notice the difference. Video fell more and more out of sync with audio (and real time) without a clear pattern for when it would happen nor how much. I only knew that it happened increasingly, so that choosing a fixed audio offset would not solve the problem.

With all these variables, you can imagine how many permutations I had to test to gather information. Sometimes I could run my camera for 30 minutes and not notice a difference and sometimes I could run my camera 10 minutes and start seeing my video fall noticeably behind. As I was thinking about what could be happening, I was ruling ingredients out, such as Flatpak, the USB hub, the microphone, the webcam (my laptop’s internal webcam seemed fine), the Zoom client, the Zoom web app on Chrome, the current version of OBS Studio… it took weeks to gather enough information to be able to ask for help in a meaningful way.

Why not just use my internal webcam? Because on it I look pink like a lobster… part of the time. I like this external USB webcam precisely because it provides a nicer and more consistent picture.

Finally, I managed to point the finger quite strongly at OBS Studio, which led me to ask on the forum. It took nearly two weeks, but someone replied not only with a helpful idea, but with a very likely explanation for all the behavior I was seeing: OBS Studio was buffering the frames and insisting on displaying “out of date” frames rather than jumping forward to the front of the queue. When the computer was under heavier load, the frame queue kept expanding and OBS Studio kept insisting on displaying frames in sequence, rather than jumping forward. The issue seems to revolve around the difficult question of which timestamps to trust coming from which clocks.

Very well, then: turn buffering off, which results in perhaps dropping more frames, but eliminates the problem of never catching up to the front of the frame queue.

Presumably this buffering also affects my laptop’s internal webcam, but I presume that external webcams connected by an external USB port are more likely to be affected by variations in the computer’s workload. I suppose if I kept OBS Studio open for 24 hours and kept my laptop busy from time to time, even a buffered internal webcam video source might fall behind real time.

So there it is. I don’t know whether I will ever regret turning buffering off, but at least for now, my voice and my face are reunited, which is plenty good enough for today.

Upgrading Discourse When You Totally Have Enough Disk Space

Tue, 21 May 2024 00:00:00 +0000

I run some forums with Discourse and I upgrade them. Sometimes, when I upgrade them, I end up in an infinite loop of sadness. There is an easy way out that doesn’t require more disk space, because sometimes, you know, you already have enough disk space.

The Symptom

Try to upgrade and you get a message telling you to free up disk space, but when you try to free up disk space by deleting unused containers, and then you have something like 7.5 GiB free, you get that message again. But… I have enough disk space!

A Workaround

According to this post at the Discourse Discourse, you can tell the upgrade script not to check for free space, but just go ahead. And it often works!

# ./launcher rebuild app --skip-prereqs

If this doesn’t work, then you actually need to free some disk space or increase the disk capacity.

Why?!

You have 7.1GB free before downloading the discourse container image but less than 5gb after downloading it when we perform the check.

Now you know.

unWise Arithmetic

Mon, 08 Apr 2024 00:00:00 +0000

My company and I bank with Wise and today, while doing a routine check of exchange rates, Wise’s UI scared the hell out of me. Fortunately, they were able to explain why it looked like their web site was bothering to throwing away the paltry sum of $10 on a currency conversion. They weren’t. It’s fine; it’s just a questionable user experience.

Please note: I have notified Wise customer support about this. Maybe they’ll do something to make it better. I’m guessing that they’ve had non-trivial internal discussion about the tension between a cleaner UI and a more-transparent UI. The ball is firmly in their court now.

The Symptom

I visited Wise’s “Convert Money” feature to see what they would give me in CAD for all the USD in my account. Their UI helpfully shows the conversion like this:

USD amount
- our fees
x exchange rate
= the CAD we would deposit into your account

I really like how clearly they present their calculation. There was only one problem: the CAD amount didn’t match the calculation. It was a difference of about $10, which is not a large amount, but is enough to look like a hidden fee, rather than a computation error. Wise’s brand is fee transparency as well as keeping fees low.

The Impact

Was there some hidden fee I didn’t know about?! Did Wise forget how to do arithmetic?! I expect them to get it right to the penny. Every. Single Time. It’s what I pay every bank for. Whatever the explanation, there is some part of my psyche that now trusts them less. I can’t be the only person.

The Problem

Wise reports the exchange rate rounded to four decimal places, however, they apply a more-precise exchange rate. When the amount to convert is large enough, a difference of 0.00005 becomes noticeable, and when they round up, it looks like I’m not getting all my money, even though I am.

The Solution

I told Wise customer support what psychological effect this experience had on me, notably on my perception of their brand. Now it’s on me to remember this for the future as well as on them to decide whether a slightly cleaner UI is worth scaring a segment of their customer base. It has become a business decision for them. I did my duty and reported the issue; I also did my best to present my opinion without undue drama.

And I believe my heart rate is all the way back to normal.

strptime: a Beginner's Mistake

Thu, 14 Mar 2024 00:00:00 +0000

I’m using jq to process CSV files to use in a Plain Text Accounting environment, specifically using hledger. I mention all this, not because it’s salient, but purely to make it easier for you to find this article by a web search.

The Symptom

$ jq -n '"8/4/2023" | strptime("%D")'
jq: error (at <unknown>): date "8/4/2023" does not match format "%D"

$ jq -n '"8/4/2023" | strptime("%m/%d/%y")'
jq: error (at <unknown>): date "8/4/2023" does not match format "%m/%d/%y"

WAT?!

The Problem

The strptime pattern %y matches the string 23, but not the string 2023. It’s pretty clear in the man page, if a little unexpected.

%y     The  year  within  century  (0–99).   When a century is not otherwise specified, values in the range 69–99 refer to years in the
      twentieth century (1969–1999); values in the range 00–68 refer to years in the twenty-first century (2000–2068).

%Y     The year, including century (for example, 1991).

The Solution

$ jq -n '"8/4/2023" | strptime("%m/%d/%Y")'
[
  2023,
  7,
  4,
  0,
  0,
  0,
  5,
  215
]

Remove a Password from a PDF Document on Linux the Super-Easy Way

Mon, 19 Feb 2024 00:00:00 +0000

My accountants sensibly send me PDFs of returns and authorization forms with password protection enabled. Sadly, this makes it difficult for me to add text and sign the document digitally, at least with my preferred PDF editor on Linux, Master PDF Editor. Every year I fail to remember how to work around this problem, so I’m writing this article, hoping that my web search will find it next year.

The Symptom

My PDF document is password protected, so I can’t do anything with it, including adding text and signing it digitally.

The Problem

Web searches for this topic return many many many irrelevant articles. It’s worse than searching the web for recipes.

The Solution

Use evince to print a new copy of the PDF document to file. This removes the passwodrd protection by default.

The Mysterious Extra Quotes that `jc` Put In My JSON

Tue, 06 Feb 2024 00:00:00 +0000

The Symptom

I try to use jc to convert a CSV file to JSON for further processing with jq. When I try to process the JSON document with jq, it fails, unable to find a value for the first cell of the first row.

When I look at the JSON document, the JSON object key corresponding the first column name in the CSV document has extra quotes around it: instead of "Date", the key is "\"Date\"". Only this key has been changed; the others are exactly as I expect them.

It seems that jc has put extraneous quotes (or extra quotation marks¹ ) around a CSV column header name.

The Cause

The CSV file has a Byte Order Mark (BOM) at the beginning, which is unprintable, so I didn’t notice it. These unprintable characters become part of the name of the first CSV column, which then becomes a key in the resulting JSON objects that jc --csv parses.

Since "\"Date\"" is not equal to "Date", chaos reigns.

The Solution

Upgrade jc to at least version 1.22.2, at least according to this issue. I was using… 1.20.4. How embarrassing.

$ pip3 install jc
$ jc --version
jc version:  1.25.0
python interpreter version:  3.11.2
python path:  /home/jbrains/ThirdParty/python-3.11.2/bin/python3

https://github.com/kellyjonbrazil/jc
© 2019-2024 Kelly Brazil

The Gory Details

I reproduce these details in order to give the next poor soul a chance to make it here by reading a single web page. Here are the steps that led me here.

I downloaded a CSV file of transactions from PayPal. (I use them against my will.)

I tried to process the CSV file with jc --csv | jq '.["Date"] | parse_paypal_date', because I’ve written a jq function to parse PayPal’s annoying date format of dd/mm/yyyy. (If I got to pass one law, it’d require ISO 8601 for all dates all the time everywhere.)

My processing command failed with

jq: error (at <stdin>:1): strptime/1 requires string inputs and arguments

I checked the CSV file and I saw a column named Date with obvious string values, starting with "02/11/2022", which is, of course, 2022-11-02 to people with taste.

After a few iterations of disbelief and confusion, I checked the JSON document.

[
  {
    "\"Date\"": "02/11/2022",

Extra quotes?!

And, BTW, when I paste the JSON output into Typora to write this article, Typora clearly shows me that there’s an unprintable character at the beginning of that key.

I’ve never seen this before, so let me check another, very similar CSV file from a different source. Was this always broken?!

Nope. Everything looks good from another CSV document that also has "Date" as the first column name.

[
  {
    "Date": "11/01/2022",

Spot the Difference!

At least now I can compare these two CSV documents and ignore the rest of the world. That makes diagnosis much simpler.

Since I can’t see a difference in the first column name between these two files, there must be an unprintable difference. How do I see the unprintable characters in a text file on the typical Linux distribution?

Today I Learned about cat -A.

$ cat -A /path/to/annoying/paypal.csv | head -n 1    
M-oM-;M-?"Date","Time","TimeZone","Name","Type","Status","Currency","Gross","Fee","Net","From Email Address","To Email Address","Transaction ID","Shipping Address","Address Status","Item Title","Item ID","Shipping and Handling Amount","Insurance Amount","Sales Tax","Option 1 Name","Option 1 Value","Option 2 Name","Option 2 Value","Reference Txn ID","Invoice Number","Custom Number","Quantity","Receipt ID","Balance","Address Line 1","Address Line 2/District/Neighborhood","Town/City","State/Province/Region/County/Territory/Prefecture/Republic","Zip/Postal Code","Country","Contact Phone Number","Subject","Note","Country Code","Balance Impact"$

TIL: Byte Order Marks

I inhaled quickly, then exhaled slowly.

I searched the web for "M-oM-;M-?" and found a non-trivial number of resuilts, which led me to learn about Byte Order Marks (BOM), thanks first to a Stack Overflow answer.

I don’t know much about Byte Order Marks, except that now I have better search keywords.

I searched the web for remove "BOM" from csv file and found a non-trivial number of results, including the authoritative-sounding “CSV and BOM character”. Unfortunately, I’m not writing PHP code using LeagueCSV, so that helps me a bit less to work around the problem. Even so, it gives me confidence that there exists some body of prior art on this subject, so I don’t need to figure this all out on my own.

I Can’t Be the First!

I went back to jc, hoping to find an issue about this, before I went charging off on my own to ~~fix~~ work around the problem. And that’s when I found this issue. And that’s when I discovered that I’m using an outdated version of jc and that upgrading might fix the problem.

And that’s when I wrote all this, while it was fresh in my mind.

I add synonyms here, not for clarity, but to attract more hits in web searches.↩︎

Ducking in Screenflow

Sat, 26 Aug 2023 00:00:00 +0000

The Problem

I don’t remember how to do ducking correctly in Screenflow. I can’t figure it out by just doing what I think makes sense. Everyone wants to provide help as a video instead of as searchable text. I’m impatient.

The Solution

Leave the music bed track, the one under the voiceover, alone. Enable ducking on the voiceover track. Adjust until happy.

LibreOffice Calc, Headers, Footers, and Every Page!

Wed, 17 May 2023 00:00:00 +0000

I prepare expense reports using LibreOffice Calc, because nothing seems to handle multiple currencies the way my company wants to do it. The details don’t matter, but it’s enough to know that I print a workbook to PDF as part of my workflow. This workbook has many worksheets. I want headers and footers on each page in order to easily see which document I’m looking at.

Suddenly, without warning, I started to see out-of-date headers on page 2 of my document. Several minutes of checking page styles and header settings didn’t change anything. I couldn’t find the magic keywords to search the web to find the problem. And then, finally, I noticed the issue: a new feature in LibreOffice 7.

The Problem

Somebody wanted to be able to use different headers on the first page from the headers on remaining pages within a single sheet page style. They added that feature. They even made it possible to keep the previous behavior of using the same headers on every page. Sadly, they didn’t make the old behavior the default choice, so it changed without my consent.

Moreover, they named the option in a way that makes sense to programmers, but not to normal, everyday humans. I didn’t notice it even after looking directly at it a handful of times.

The Solution

Open the Styles panel and locate your page style.
Modify….
Choose the tab Header.
Locate the new option “Same content on first page”. It’s probably disabled, so enable it!
Press Edit…. Notice that now there only one tab for the header.

LibreOffice Calc will now use this one header on every page of your PDF document.

If you’d like to see the difference, disable the option Same content on first page, then edit the headers again. Now notice that there are two settings tabs: one for the first page and one for the rest of the pages.

Now check your Footer settings.

A UX Suggestion For Everyone

When you add a new feature with configuration settings, give those settings default values that match the previous behavior, so that you don’t confuse users. Thanks.

Hang Out With J. B. Rainsberger

Byobu Session Name in Terminal Window Title

Turn Titles On in tmux

Remember These Settings Forever

Further Reading

Viewing HEIC (HEIF) Images on Pop! OS 22.04

The Solution

The Symptom

Attempt 1

Video Gradually and Increasingly Falling Behind: Don't Use Buffering

A Fix?

Key References

Some Details

Upgrading Discourse When You Totally Have Enough Disk Space

The Symptom

A Workaround

Why?!

unWise Arithmetic

The Symptom

The Impact

The Problem

The Solution

strptime: a Beginner's Mistake

The Symptom

The Problem

The Solution

Remove a Password from a PDF Document on Linux the Super-Easy Way

The Symptom

The Problem

The Solution

The Mysterious Extra Quotes that `jc` Put In My JSON

The Symptom

The Cause

The Solution

The Gory Details

Spot the Difference!

TIL: Byte Order Marks

I Can’t Be the First!

Ducking in Screenflow

The Problem

The Solution

LibreOffice Calc, Headers, Footers, and Every Page!

The Problem

The Solution

A UX Suggestion For Everyone

Turn Titles On in `tmux`