Failing DVI / VGA to SDI / HDMI conversion

Hello,

I need to convert the video signal from a PC to HDMI or SDI. The PC is a Kontron CP308 running Ubuntu 16.04 LTS, It has a VGA and a DVI output.
When connecting the PC to a standard PC monitor, no problem.

I bought 2 different DVI to HDMI converters and 2 different VGA to HDMI converters. When connecting the PC monitor in HDMI to any of these 4 converters, no problem either.

I'm now trying to get the video on a VideoAssist, but it doesn't work. Here are the tests I made:

• PC > BMD DVI extender > VideoAssist SDI in: no image
• PC > DVI/VGA to HDMI converter > Decimator 12G Cross > VideoAssist SDI in: no image
• PC > DVI/VGA to HDMI converter > VideoAssist HDMI in: blinking image & VideoAssist crash
• PC > DVI/VGA to HDMI converter > BMD Micro converter 12G HDMI to SDI > VideoAssist SDI in: blinking image & VideoAssist crash
• PC > DVI/VGA to HDMI converter > AJA Ha5 12G > VideoAssist SDI in: blinking image & VideoAssist crash
• PC > DVI/VGA to HDMI converter > Teranex AV > VideoAssist HDMI or SDI in: working

This setup will be abord a battery powered scientific submarine, I have to make it as small & power efficient as possible. The Teranex is thus not a good fit for this task and I need to get it working using a smaller converter.

When the VideoAssist crashes, I need to remove its batteries to be able to restart it.

I also forced Ubuntu to output 1080p60 using xrandr with no luck. The Teranex AV correctly reports 1080p60.

What can be different between the Teranex AV and for instance the Micro converter? Does anyone knows another Ubuntu setting I could try changing appart from the resolution & framerate?

Thanks in advance

The problem may be that it is not running at a true HDMI resolution.
I had to use this https://gefen.com/product/vga-audio-to- ... -converter
to get my VGA signal to be a solid 1080p or 720p signal to take into a BlackMagic Atem Mini

You can get them on B&H or many different websites. It is a little pricy, but it worked solid for me.

Apart from resolution and framerate it could be an RGB vs YUV issue. The Teranex AV supports automatic RGB detection, I believe the HA5 and Decimator need to be setup manually. The VA and BM microconverters only support YUV 4:2:2.

Good Luck

The problem may be that it is not running at a true HDMI resolution.
I had to use this https://gefen.com/product/vga-audio-to- ... -converter
to get my VGA signal to be a solid 1080p or 720p signal to take into a BlackMagic Atem Mini

You can get them on B&H or many different websites. It is a little pricy, but it worked solid for me.

Does it handle all (text mode, 320x200, etc) VGA modes properly ?

Hello,

Thanks all for your replies. Howard was right I think, and I managed to get a working signal using the Decimator, by activating the "freerun" sync option. There's no RGB/YUV setting on the Decimator, I guess it does it automatically.

Using the AJA and activating the RBG/YUV conversion I nearly got a usable signal but I have black frames every now and then.

So it seems that there's both a RGB/YUV conversion to do and a synchronisation problem. Only the Decimator (and the Teranex AV) can fix both properly (unless I missed a setting on the AJA).