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Comment by gblargg | Hacker News Reader

This reminds me of car safety features, how drivers have become more complacent to offset the benefits. QR codes were made to be robust in the face of errors, but over time this has been eaten into for aesthetic purposes. Businesses commonly put a logo in the center, eating up some error correction budget. This likely has a similar effect.

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A few weeks ago I saw the first QR code I've personally witnessed that I'm pretty sure is completely unscannable. The company logo stretched well out of the center block. It was on the back of a semi in the Chicago area. I didn't get the greatest shot of it on my phone (as a passenger), because it was driving away as I tried, so it wasn't quite proof it couldn't scan, but I'm pretty sure it ate more than 100% of the error correction margin.

Based on the trends, I expect it is only the first of several I will see.

I’ve run into a few of these. And yesterday some kind of payment scanning QR code at SF’s Filipino Pistahan festival didn’t scan and I had to type in the text below. Annoying.

Doesn't everyone QA their QR codes? I thought it would be as obvious as making sure you got the right address and/or phone number on an ad before distributing it.

You'd think. My local authority is reorganising refuse collection and did a mailshot to let everyone know the new collection rota. Then they did another because the dates on the first one were wrong. The incompetence is staggering.

Maybe they do. Do QR code decoder authors QA their decoders to be sure they are getting high accuracy of the raw data? You could make a poor decoder that relies on the error budget to work, while someone checked with a high-quality decoder. Tech with error correction invites corner-cutting. Hard drives, flash storage, even DDR5 RAM does this. Use crapper representation or reading devices and just add more error correction.

I always find it funny when companies don't put any attempt to shorten the URL, filling it with plaintext url parameters, resulting in huge QR codes that can barely be scanned due to the density.

related: seeing outlook safelinks as QR codes, so you have the recipients email address embedded as well

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