Discount (or even grey market) electronics can be economical ways to get a job done, but one usually pays in other ways. [Majenko] ran into this when a need to capture some HDMI video output ended up with rather less than was expected.
Faced with two similar choices of discount HDMI capture device, [Majenko] opted for the fancier-looking USB 3.0 version over the cheaper USB 2.0 version, reasoning that the higher bandwidth available to a USB 3.0 version would avoiding the kind of compression necessary to shove high resolution HDMI video over a more limited USB 2.0 connection.
The device worked fine, but [Majenko] quickly noticed compression artifacts, and interrogating the “USB 3.0” device with
lsusb -t revealed it was not running at the expected speeds. A peek at the connector itself revealed a sad truth: the device wasn’t USB 3.0 at all — it didn’t even have the right number of pins!
A USB 3.0 connection requires five conductors, and the connectors are blue in color. Backward compatibility is typically provided by including four additional conductors, as shown in the image here. The connector on [Majenko]’s “USB 3.0” HDMI capture device clearly shows it is not USB 3.0, it’s just colored blue.
Most of us are willing to deal with the occasional glitch or dud in exchange for low prices, but when something isn’t (and never could be) what it is sold as, that’s something else. [Majenko] certainly knows that as well as anyone, having picked apart a defective power bank module to uncover a pretty serious flaw.