Yea those specs should be plenty especially since you are doing most encoding on the capture card, I would disregard the comments about changing your output solution and focus on possibly a BM Duo or Quad assuming they do have the option to sync clocks as suggested. Keep in mind that to achieve true equal line latency at the other end of your output is going to require some strict hardware tolerances as well, even down to the cable choice can make the difference between a couple lines.

That will do it, it either needs to be a dual input (or better) or you need another matching card. I believe it was mentioned by someone that your current mini cards do not support this.

Also, the decklink quad is not capable of inputting and outputting on the same channel at the same time. It is not full duplex.
So you have 4 input or output cards, free to choose which one does what.
So if you assign 2 as output, you only have 2 channels left.

There also is a decklink quad 2 that can either input or output 8 channels, with external sync.
This card is not available yet but should be any time soon.

Let me check the duo for you if I get some time somewhere the coming days.

I tried it, and indeed they are running in perfect sync, thanks! However, our gtx 950 is having only 1 hdmi output, and another displayport that needs to be converted to hdmi first. After that we have some cheap hdmi to sdi converters of 35$ running, and it's those that i don't really trust.

We used them until now in our setup, because we didn't really care about 1 frame difference, but now that it becomes so critical, I'm not sure they will deliver. Changing them for 'pro' converters will cost us almost the same as an AJA card.

Where vmix can tell us how many frames were dropped on the external output, in case of any, the displays we have no info at all about this. In case we don't find another solution, I will go for this, but I'd rather have some way of monitoring in case it goes wrong :)

Sorry to spam my own topic, but so many questions.. Wish I had built up some broadcast experience in the 'traditional' sector before starting a broadcast company with vmix and a few gopro's lol :) Now I got to figure out everything from zero..

Anyway..

I just saw that prices on the Kona3 from AJA are also very low, you can get those cards with the breakout box for 250 euro, which is dirtcheap.

The only difference between kona 3 and 3g would be an added hdmi 1.4 port, according to google. And.. Vmix seems to support the 3g.

Since Martin mentioned that AJA has an internal clock on their capture cards, this might be a good deal?

Also, the manual mentions this:

If you have a sync generator or central
piece of video equipment to use for synchronizing other video equipment in your
studio, then connect its analog composite output to the KONA 3 reference input.
When KONA 3 outputs video it uses this reference signal to lock to. When
connecting a reference video source, the locking signal should be the same format in
Hz (1080i29.97, 625i25, etc.) as the Primary format selected in the KONA 3
Control Panel. It is possible in some circumstances to use an alternate format video
signal as long as the basic frame rate is compatible (for example, using a 525i29.97
genlock signal to lock a system running 1080i29.97)—if the Hz coincide.


Am i on the right track here?

Allright, this clarifies already something :) I thought it wasn't the inputs, because 1 external output dropped frames, while the other one didn't and both had the same camera as an input. But, we are using very cheap hdmi>sdi converters to feed the inputs, so that could clarify a lot..

Anyway, would that mean i would have to swap out the yuan card for something that supports an external clock? A decklink quad for example?

Our displayport to hdmi adapter is a passive one, but i prefer to go this route as a last resort. It will look messy to our client, with all those converters, and there will be no way for us to tell if we are dropping frames, unless getting an angry phonecall from the OB truck. I prefer to have everything under control and see some statistics in front of me :)

What am i missing here? from the original picture he posted it seems clear that one input is clearly behind the other. why start worrying about outputs if the input are out of sync to begin with thus throwing everything else down the line out of sync?

Indeed I think it's better to focus on the outputs, since there is a difference in the amount of frames they drop. If the input camera would drop a few frames, and both outputs would be synchronised, they would both drop the same frame, and there would be no problem in the ob truck, since everything would still be sync. Also, it will be impossible anyway to genlock all inputs, since the fs700 doesn't have any genlock anyway.

Does it really matter if frames are dropped on the output so long as the feeds are synced? That's what a dropped frame is, a frame that is skipped in order to ensure the timecode is respected above all else. Also are all of your frame rates matched across the board from source to destination?

* Render time: 10- 12 ms, with a single video played. With 2 video inputs it's about the same.

Latency of the mini monitors: 20-40ms

I will now start experimenting by putting hardware acceleration and stuff on and off, and see if it makes a difference. also I will install all drivers again.

* The motherboard should be allright I guess, we use it already for some time. For example during New Year, we recorded + streamed an event with 5 HD cams for 15 hours where we had less then 10 dropped frames over the course of the night on the recording.

* I already dropped the idea of the Kona 3, because I found a post with someone from AJA saying it's not supported. Maybeye I will put a feature request, because you can find these second hand at 250 euro including the breakout box nowadays, giving you 4 HD in or outputs. People are throwing them at you on ebay and marketplaces, because many software packages don't support it anymore, while it's super nice hardware, even after being 6 years old :) Might be a good starter card for many who want to get cheaply into broadcast and vmix!

*FS700 indeed doesn't have genlock, but anyway, it's not the inputs that matter here I think.