The One with the Thoughts of Frans

Archive for Software

Why Windows Is Better Than PulseAudio

Wait, what? You heard me. On Windows you can set sample rates per sound card. It looks like this.

Setting one soundcard to 24 bit, 96 kHz in Windows. Windows refers to this as “Studio Quality.”

In PulseAudio you’re limited to a primary and secondary sample rate. I’ve actually been using pasuspender more, also because its AC3 passthrough never seemed to work.

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Is My Firefox Out of Date?

When I logged in, WordPress tried to inform me that the particular browser I was using was out of date.

WordPress’ “Your browser is out of date” greeting.

So, is it?

Well, we can take a look at the Firefox ESR download page to find out.

The current version of Firefox ESR is 52.4.1, releasenotes here.

Nope. Still Firefox 52, which will remain supported until Firefox 60.

The Firefox support window. Source: https://www.mozilla.org/en-US/firefox/organizations/faq/

Always fun, these automated checks. 🙂

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Steam Error: “invalid depot configuration”

I just had to share this mysterious error message.

A screenshot of a Steam error dialog that says invalid depot configuration.

Simply retrying made it go away.

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Image Optimization Guide

On the forum I administer, I am forced to run a tight attachment policy. Disk space doesn’t grow on trees. Occasionally this leads to questions about the small attachment size limit of 50 KiB. This guide is intended to clarify that this is not nearly as tiny as you might think. Note that although I’ll mention commands without much explanation for the sake of brevity, you’re always recommended to further explore the possibilities offered by those commands with the --help flag as well as by running man the-command-here.

First you need to ask yourself what kind of file type is appropriate, if you have the choice. On screenshots, the main purpose of attachments on my forum, you’ll often encounter large areas of uniform background colors. PNG is therefore almost invariably the right choice. Crop out everything but what’s relevant. JPEG is appropriate for more dynamic pictures such as photographs. If you want to do a lot with photographs, you might want to consider an external hosting service. My wife likes SmugMug. Still, for thumbnails you might be able to do a fair bit more within a few hundred KiB than you might think. Finally, the vector graphics in SVG result in pictures that always look sharp. You’ll typically have drawn these in a program like Inkscape or Adobe Illustrator.

Table of Contents

  1. 1. Optimizing JPEG
  2. 2. Optimizing PNG
  3. 3. Optimizing SVG
  4. Addendum A: Scanned Documents
  5. Addendum B: Video

1. Optimizing JPEG

Often you’ll want to crop your file. Do not edit your JPEG followed by resaving it because this will result in reduced quality! You can crop losslessly with cropgui. On Windows you can use IrfanView.

If you don’t want to crop, and also potentially for some post-cropgui optimization, use jpegtran -copy none -progressive -optimize file.jpg > file-opt.jpg. Note that this will get rid of all metadata, which may be undesirable. If so, use jpegtran -copy all -progressive -optimize file.jpg > file-opt.jpg.

Of course if you want to scale down your JPEG there’s no point in mucking about with lossless cropping first. After scaling down, check how low your quality can go (also see a little helper script I wrote). In any case, you should avoid introducing any unnecessary compression steps with associated quality loss. Here are some results:

  • The original 11.jpg at 2.19 MB.
  • Losslessly cropped 11-crop.jpg at 1.11 MB.
  • Optimized with -copy all -progressive -optimize 11-crop-opt.jpg at 1.04 MB. -copy none would’ve saved an extra whopping 40-some KiB, which on this kind of filesize has little benefit, and besides, I quite like the metadata. For thumbnail-sized files the balance is likely to be different. For example, the 52.2 KiB SmugMug auto-generated thumbnail below can be insignificantly reduced to 51.1 KiB with --copy all, but to 48.2 KiB with --copy none. I think an 8% reduction is not too shabby, plus it brings the file size down to under the arbitrary 50 KiB limit on my forum.

2. Optimizing PNG

As I wrote in the introduction, for screenshots PNG is typically the right choice. If you want to use lossless PNG, use optipng -o7. In my experience it’s ever so slightly smaller than other solutions like pngcrush. But as long as you use a PNG optimizer it shouldn’t much matter which one you fancy. Also see this comparison.

If you don’t care about potentially losing some color accuracy, use pngquant instead. To top it off, if you really want to squeeze out your PNG, you can pass quality settings with --quality min-max, meaning you can pass --quality 30-50 or just --quality 10. Here are some quick results for the screenshot in the SVG section below, but be sure to check out the pngquant website for some impressive examples.


$ du -h --apparent-size inkscape-plain-svg.png
27K	inkscape-plain-svg.png

$ du -h --apparent-size inkscape-plain-svg-fs8\ default.png 
7.6K	inkscape-plain-svg-fs8 default.png

$ du -h --apparent-size inkscape-plain-svg-fs8\ quality\ 10.png 
4.3K	inkscape-plain-svg-fs8 quality 10.png

In this case there is no visual distinction between the original PNG and the default pngquant settings. The quality 10 result is almost imperceptibly worse unless you look closely, so I didn’t bother to include a sample.

3. Optimizing SVG

For using SVG on the web, I imagine I don’t have to tell you that in Inkscape, you should save your file as Plain SVG.

Save as Plain SVG in Inkscape.

What you may not know is that just like there are lossy PNGs, you can also create what amounts to lossy SVGs. There are some command-line tools to optimize SVGs, including (partially thanks to this SO answer):

  • Scour is probably the best command line tool for some quick optimization. You can just use the defaults like scour < in.svg > out.svg or scour -i in.svg -o out.svg. But I recommend you go further.
  • SVGO (SVG Optimizer)
  • SVG-optimiser (by Peter Collingridge)
  • SVG-editor (by Peter Collingridge)

My personal preference for squeezing out every last byte goes toward the web-based version of the SVG-editor by Peter Collingridge. By running it in a browser with inferior SVG support such as Firefox, you’ll be sure that your optimized SVG still works properly afterward. The command line tools can only safely be used for basic optimizations, whereas the effects of going lossy (such as lowering precision) can only be fully appreciated graphically.

Addendum A: Scanned Documents

Scanned documents are a different item altogether. The best format for private use is DjVu, but for public sharing PDF is probably preferable. To achieve the best results, you should scan your documents in TIFF or PNG, followed by processing with unpaper or ScanTailor. If you’ve already got a PDF you’d like to improve, you can use pdfsandwich or my own readablepdf.

Addendum B: Video

I’m not aware of any lossless optimization for video compression such as offered by jpegtran, but you can often losslessly cut video. In the general purpose editor Avidemux, simply make sure both video and audio are set to copy. There is also a dedicated cross-platform app for lossless trimming of videos called, unsurprisingly, LosslessCut. If you do want to introduce loss for a smaller file size you can use the very same Avidemux with a different setting, ffmpeg, mpv, VLC, and so forth. You can get reasonable quality that’ll play many places with something like:

ffmpeg -i input-file.ext -c:v libx264 -crf 19 -preset slow -c:a libfaac -b:a 192k -ac 2 output-file.mp4

For the open WebM format, you can use something along these lines:

ffmpeg -i input.mp4 -c:v libvpx -b:v 1M -c:a libvorbis output.webm

More examples on the ffmpeg wiki. Note that in many cases you should just copy the audio using -acodec copy, but of course that’s not always an option. Extra compression artifacts in audio detract significantly more from the experience than low-quality video.

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UNetbootin Custom Drive Selection

UNetbootin has been broken for many, many years, but just today (a few years after the fact) I discovered that the previous GUI option to show all drives was readded as a command line option. So if the program doesn’t want to detect your drive, just use the targetdrive argument:

unetbootin targetdrive=/dev/sdf1

And voila, it’s working. I have no idea why it should have to be so difficult. The program categorically refuses to detect any of my USB flashdrives or harddrives, so since the removal of show all drives it’s been utterly useless.

PS This is basically only for Windows ISOs. For everything else you can just use, e.g., dd. Much easier.

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Switching to FreshRSS

QuiteRSS is a terrific piece of software. It only has one flaw, which is that it only runs on my desktop. Unfortunately this has led to me increasingly getting behind on the things I like to read. Sometimes this is fine, like when I can read a book instead, but other times it’s mildly frustrating.

QuiteRSS in three-column mode.

It would seem that none of the online feeds readers, whether self-hosted or SaaS, support the paradigm I’m used to. They’re all following the “golden standard” of nightmarish, thankfully-it’s-gone Google Reader. Basically I use feeds like emails. Most I delete after reading. Those I want to keep for reference I keep around, marked read.

But not so with these feedreaders. Feeds you want to keep for later reading should preferably be favorited, bookmarked, or maybe saved to a system like Wallabag. This has advantages too, of course. By centralizing your to-read list in one location, like Wallabag or Pocket, you don’t have the problem of remembering what’s where, or that you have loads of unread open tabs in various browsers.

Long story short, after sampling a whole bunch of feedreaders I opted for FreshRSS. It suffers from the omnipresent “no pages” disease. Got a feed with a thousand items? (Yes, they exist.) You can go to the start or the beginning by sorting in ascending or descending order, but reading things somewhere down the middle? Forget it.

These minor inconveniences are worth it, however. This way I can easily read my feeds from any computer anywhere in the world. The feeds are always updated, provided you set up a cron job. I don’t have to start up my computer or risk missing anything if I’m on vacation for a few days. I can quickly check them on my cellphone during an otherwise wasted moment. Overall I’m happy. Goodbye, QuiteRSS. You were a good friend after Opera died, but it’s time to move on.

PS Here are some feed-related links that should go along nicely with any feed reader.

  • Feed Creator allows you to create feeds for webpages that are missing them.
  • So does RSS-Bridge, but since it’s self-hosted it fits perfectly next to FreshRSS in the kluit spirit.
  • Tubes is a tool I wrote a few years back that can filter and fix up feeds. Useful if a website happens to have a feed, but not on a per-category basis or some such. Or of course because you might want to subscribe to an hourly news podcast, but only get the news once a day.

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Cloud, Kluit, Clod?

Just a quick demonstration of the power of openclipart.org. I dubbed my “personal cloud” experiment kluit: a Dutch word meaning both clod and the ball of earth around the roots of a tree. In other words, kluit is firmly grounded because you’ve got your own ground with you wherever you go. Be like Dracula. With a name in mind, I also wanted a matching logo. Following a quick search for leaves, root (or was it tree) and after a little initial play something like attraction, this is the quick and satisfying result.

A couple of floating leaves still connected with their roots. This arrangement symbolizes how creating your personal cloud keeps it grounded.

And of course the remix is free for all. Enjoy.

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SSH publickey denied?

I was suddenly having trouble connecting to GitHub, after pulling in an OpenSSH update to version 7. Chances are that means the problem is security-related, meaning it’s worthwhile to take the time to investigate the cause.

$ git pull
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

A little debugging showed the following:

$ ssh -vT git@github.com
OpenSSH_7.1p2 Debian-2, OpenSSL 1.0.2f  28 Jan 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to github.com [192.30.252.130] port 22.
debug1: Connection established.
[…]
debug1: Skipping ssh-dss key /home/frans/.ssh/id_dsa for not in PubkeyAcceptedKeyTypes
[…]
debug1: No more authentication methods to try.
Permission denied (publickey).

Of course I could quickly fix the problem by adding PubkeyAcceptedKeyTypes ssh-dss to ~/.ssh/config, but checking OpenSSH.com tells me that “OpenSSH 7.0 and greater similarly disables the ssh-dss (DSA) public key algorithm. It too is weak and we recommend against its use.” So, although I could obviously re-enable it easily, I guess I’ll have to generate a new key. I hope GitHub’s guide is accurate for generating something sufficiently secure, because I’m kind of ticked off that something I generated in 2013 is already considered “legacy.” I hope I’m to blame and not an earlier version of GitHub’s guide.

Incidentally, to change the passphrase one would use the -p option, e.g.:

ssh-keygen -f id_rsa -p

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LuaLatex Font Hassles

The TeX Gyre Pagella font I was using turned out not to contain Cyrillic characters. Unfortunately, fontspec doesn’t seem to have an easy means of setting a fallback font — I checked the manual, I swear! So I found a lookalike font named Palladio Uralic and used it instead. Before you can use a newly installed font, you have to run luaotfload-tool --update.

%So is Palladio. Used as fallback. Thanks to http://tex.stackexchange.com/a/37251/32003
\newfontfamily\palladio{Palladio Uralic}
\DeclareTextFontCommand{\textpalladio}{\palladio}

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LaTeX: combining added margins with hanging indents

Since I’m using KOMA, the obvious method would seem to be:

\begin{addmargin}[1cm]{0cm}
	Yada.
\end{addmargin}

Unfortunately, that doesn’t seem to combine with the hanging environment. So I did it a little more manually, which will probably have someone shaking their head while I’m stuck feeling pretty clever about it:

\parindent=1cm\hangindent=2cm Yada.

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