HDMI adapter teardown

Article By : Brian Dipert

An inexpensive HDMI-to-USB converter doesn't support interlaced video inputs or greater-than-HD output resolutions, but still delivers a notable "bang for the the buck."

Within a recent write-up covering how I was able to tether a HDV camcorder to my computer for use as a webcam (see “Repurposing a HDV camcorder for the home office“), I wrote:

Its [the Canon VIXIA HV30’s] HDMI output is 1080i60 (1920 horizontal pixels, 1080 vertical pixels, interlaced, with a 60 fields per second rate), whereas low-priced HDMI-to-USB converters generally only accept progressive-scan inputs (and a limited set of resolution and frame rate options, at that).

At the time I wrote those early words, I’d already bought one of those low-priced HDMI-to-USB converters—two, in fact; I’ll get to that in a minute—and since it ended up being unusable for this particular setup (although it’d be perfectly acceptable for many; the interlaced-output quirk of my camcorder is relatively rare, from what I can ascertain), I’ve decided to sacrifice it on the altar of curiosity as a teardown victim.

Here’s a stock photo, to start:

These widgets frequently pop up on (and just as quickly disappear from) Amazon and other retailers, from a variety of suppliers at a variety of prices. As I write these words, for example, one from NeuTek is selling for $24.55 on Amazon. They all look the same because they apparently are the same. I bought the unit showcased today from Hilltrade-via-Amazon in mid-August for $16.71. One week earlier, I’d picked up an identical unit, this time sourced from Polok (again with Amazon as the retailer intermediary) for $11.28 (both purchase prices were promotion-discounted). Here are the backs of both boxes:

As you can see, they’re identical save for the white stickers slapped on them prior to shipping the units out of the factory (for all I know, these are all “shell” companies for the same corporate entity). So why did I buy two? From pre-purchase research I knew that they tended to run “hot,” and with longevity therefore in mind (and at those low prices) I picked up a spare.

Note, too, the claimed FCC and CE certification stamped on the back of the box, although I was unable to find a specific certification ID anywhere on the packaging, documentation or device itself. Given that the product is originally sourced from China, this snippet from Wikipedia may hold the clue as to why (as with Elgato’s conceptually similar Cam Link 4K, which I ended up using instead, this is a Part 18 FCC device):

Electronic products sold in parts of Asia and Africa hold the FCC label even though it holds no legal significance, and also without any means to verify whether they actually conform to the specified standards or not.

What’s the point of including a FCC mark if it can’t be proven valid, except to intentionally deceive? And apparently the FCC and/or other relevant government entities aren’t capable of cracking down on fraudsters, either? Sigh…

Rant over, here are some more outer box perspectives:

Time to dive inside:

Aside from the device itself, there’s only a six-panel double-sided quick-start guide, printed in English on one side and Chinese on the other:

Since the device is USB Audio and Video Class-compliant, as well as being self-powered by the USB bus, there’s no software included (or needed, for that matter), nor a wall wart power supply…err…supplied. These close-ups of the English-side literature are particularly enlightening in terms of both device capabilities and system requirements:

As for the device itself, here it is, as usual alongside a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes:

I was a bit worried about how to get inside the aluminum case, until I saw the screws on either end:

As expected, an additional screw was lurking underneath each of the stickers, and removing them gave me my first glimpse inside (one of the four screws stubbornly “sat and spun” in place without retracing much, but I was able to prod it into action by inserting a separate thin flat head screwdriver tip, used as a lifting lever, underneath its head):

As you can see from its use in the prior photo as a prop-up, my iFixit 64-bit Driver Kit, now referred to as the Mako, was as-usual pressed into service in this project. The PCB slid out with only a little “push”:

This left only a bit of adhesive residue behind in the now empty enclosure:

And now we finally have unobscured views of the PCB:

Let’s focus on the bottom side first. My fingernail was only able to make partial headway at getting rid of the black adhesive “goop” that holds the PCB in place within the enclosure but some patience, some rubbing alcohol and a switch to a larger-than-before flat head screwdriver (this time employed as a chisel) got most of it off, unfortunately revealing a fairly unremarkable PCB landscape underneath:

The PCB topside was more interesting. Liberal application of a heat gun’s active output prodded the heat sink (which is curiously not also connected directly to the metal case via thermally conductive tape or the like, instead relying solely on passive thermal transfer to the enclosure and from there to the ambient air) to detach:

And although the markings on the IC underneath it were quite faint (not to mention made opaque by the remaining thermal paste film atop it, which resisted all heat, rubbing alcohol and scraping attempts to remove it), my inexpensive magnifying glass revealed it to be MacroSilicon Technology’s MS2109, an SoC that combines a USB 2.0 controller and data transceiver, a HDMI receiver, and an audio and video processor:

In this particular system implementation, USB 2.0 is the exclusive audio output option; the IC’s discrete S/PDIF output isn’t extended to the outside world. And speaking of USB 2.0, its documented top-end implementation existence reveals another bit of deception that I occasionally encounter in products based on the MS2109. They sometimes claim USB 3 compatibility (although the ones I bought didn’t do this), thereby inaccurately implying that the device is capable of “4K” etc., output video resolutions and high frame rates.

While I suppose that stating USB 3 forwards-compatibility wouldn’t be completely off-base, it implies capabilities that the associated devices aren’t able to deliver. In contrast, to be clear, the Elgato Cam Link 4K (which is apparently based on a Lattice Semiconductor ECP5 FPGAis UHD output-capable. That all said, the MS2019’s pervasiveness has led to lots of interesting hacking projects, which a simple Internet search will expose; here’s one, for example.

I’d also like to draw your attention to the word “softy” printed on the PCB next to the HDMI input jack. It’s the name, I believe, of the original manufacturer, who also sells the product under its own brand name in some markets. Other notable ICs discernable on this side of the PCB include an Advance Monolithic Systems AMS1117 (PDF) 1A low voltage dropout regulator and a Shenzhen First-Rank Technology T24C08A 8 Kbit serial EEPROM. What else of interest do you discern, on the PCB and/or the system more generally? Sound off in the comments with your thoughts!

This article was originally published on EDN.

Brian Dipert is Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.


Leave a comment