BMD HDMI/SDI micro converters

  • Having experienced catastrophic performance from 3 pairs of these HDMI/SDI converters I would not wish on my worst enemies  I've just acquired the new Blackmagic HDMI/SDI micro converters & am using them to connect my MBP to an Optoma video projector of 1280x800 resolution. But MacOS, Isadora and Matrox now see the projector as 1920x1080. Anybody has experience with BMD micro converters. Is this normal with the converters or am I doing something wrong? I began tinkering with switchResX but beat quick retreat as it doesn't seem friendly with neither BMD nor High Sierra. 

  • Hi,

    1280 x 800 is not a standart video resolution. ( It's 16/10, a computer graphic resolution ).

    Your Blackmagic converters only accepts video standarts. Check in the tech. specifications on the website, you will find a list of supported resolutions.

    It accepts 720p50 that might fit your needs.

    But you will never be able to use the native resolution of your beamer ( 1280x800 ).


  • Mehdi is right. its not like you are driving your Optoma directly any more. now you are driving the BlackMagic device and that is driving your projector. you will need to find a resolution that works for the BM and then let the projector scale that. I use a BM Mini Monitor with an Optoma and don't need SwitchResX, just set the BM with the BM software or directly from inside Isadora, using the Stage Mirroring facility. Even though the Optomas are native 1280 x 800, they accept 1080p and 720p no problem, but be aware that the BM is 16:9 aspect and 1280 x 800 is 16:10 and you might need to set the Optoma to 16x9 or use IzzyMap to compensate for the change in aspect.

  • @msanii To give a bit of background, the blackmagic convertors (and anything that uses SDI is limited to a subset of the SPMTE standard. SDI is only designed to carry standard video formats, these are clearly listed on the blackmagic specs. As others mentioned 1280*800 is not a SMPTE standard and will not pass over SDI. Barco have implemented a 16:10 option in their non standard SDI protocol, but this will only talk with other barco products.

    For extending non SMPTE signals there is always HD-BASET which is also great and reliable if you have a good set of tranceivers, although more expensive than the SDI pathway. It will allow all those computer resolutions though.

    As an aside, I have used the convertors that you had troubles with for quite some time (I have 5 or so pairs of them). I have never had a problem with them, but, one thing I did notice is they need a better power supply than is often shipped with them (but this changes depending on where you get them). I was using 12v 1+amp and they have never given me any trouble over the 5 years I have been using them. Having said that, the micro convertors from black magic have now dropped a lot in price and there is no real reason to go with the the cheapies.

  • @keftaparty Thanks for the reminder on video vs computer graphics resolution. The display formats available on the optoma_W316ST (4:3/16:10/LBX/Native/Auto) don't display the the 1920 image received from the BMD converter with correct aspect ratio. The Native format setting displays correct aspect ration but it crops into the image along the blue frame in the image below:  

    I like this optoma due to its cost/short throw capability/relative lumens.

    @dbini I guess I'll try setting to 16:10 and compensating with IzzyMap to see how it works. I wonder what that might entail as regular workflow.

    @Fred Thanks for the background. I'll definitely investigate HDbaseT and good transceivers for more flexibility for projects where this may be necessary. My Optoma/Matrox setup is a low cost configuration and may not be with the investment. I may be better off limiting it to short runs of HDMI situation and plan for a regular 1920 compartible setup.

    Interesting you've not had trouble with the Tandek converters. I used them with a variety of upto 30m SDI cables and performance was very imprevisible. We'd spend hours tinkering. What is for sure is that they never worked with the Matrox, I had to connect directly to the computer for the m to work sometimes. Perhaps it was the power supply. In addition the power stability wasn't so good where we were. I must try them with better power supply.

  • Matrox units do not put out spmte compliant signals, but they are close, some convertors with a lot of tolerance, or rigorous re-clocking will pass the signal, many will not. I would guess that is why you had trouble with the cheap convertors.

  • @msanii - i have 3 of those Optoma W316ST units. (2 old black ones and a newer white one) - i agree that the short lens is very useful and the lumen to cost ratio is good. don't ever point them far from horizontal, this kills the DLP over time. i set one to point about 50 degrees down to map onto a floor and after a few hours running like this a bunch of pixels turned white. now every time i use this one i get more white pixels, no matter how i use it, so its now a rehearsal/backup unit.

    in fact, while we're talking about 1280 x 800, it would be lovely if IzzyMap had this as an option in the resolution dropdown without having to type it in as a custom res every time..... (#feature request???)

  • I got 2 of the new ones, awaiting to acquire a third one. I've had to send one of them back for repair as the HDMI has stopped working after 2 months of use. Thanks for the tip about installation angle. That's a major concern for me as projecting onto the floor/roof is a frequent design intention. Optoma don't seem to contra indicate against it.

    yes I support a feature request for 1280x800

  • @msanii - i built a bracket with a mirror to facilitate downwards projection. because of the asymmetric throw, its a bit of a weird design and it keystones massively, but i've used it for a few projects.

  • @dbini - ofcourse! I must try it out. Many thanks for the suggestion.