Blackmagic Forum

Hello,

I would like to de-embedde a SDI 4k DCI or UHD to 5.1 audio.

I just changed all my installation, I was in HD before and used two SDI->AUDIO converter from BM, but... it doesn't work if my SDI is 4k.

Before to buy two new SDI->AUDIO 4K, i would like to know if there is a solution to convert a SDI 6g or 12g to SDI 3g. I can't find that with Blackmagic product. Do you have any idea ?

Best

Robin

Hello Robin,

we use an AJA 12GM to "translate" our 4K DCI 444 signal to an understandable signal for our Teranex setup to then de-embed this signal. This isn't the cheapest solution, but it works for us until maybe BMD fixes the Teranex input problems.

Hello,

Thank's for you input.

Aja just told me the same. But do you use it to de-embedded the audio or to convert the 12SDI to something elese ?

What is your Teranex model ?

My work flow is this one :

- Output from UltraStudio 4k mini
-> SDI A to Teranex HDMI 8K HDR (to go to my projector 4K with 3D LUT)
-> SDI B to two Audio Mini converter to output a 5.1 signal.

but of course those converters only accept 3g signal... Aja solution is ok but not cheap.

AJA told me the 12G will be splitted in 4x3G SDI and the audio will be on SDI 1. Do you think this Teranex could do the same ? Teranex Mini - 12G-SDI to Quad SDI, the manual doesn't speak about audio...

What do you mean by Input Problems on Teranex ? My problem with Teranex HDMI 8K is it converts everything in YUV. Impossible to output a RGB signal from it.

Best

Robin

Hey Robin,

we use the AJA device just to "flatten" the 12G SDI from a Decklink output and then push the signal through 3x Teranex Mini SDI to Audio 12G. Each Teranex Box de-embedds 2 channels of audio, so for our 5.1 monitoring we need 3 in total.

I wouldn't buy a Teranex Mini 12G to Quad SDI because the device fails at receiving 4K DCI 444 signals, it only works with 422 @ 4K DCI, and we are still in contact with Blackmagic to find a fix.

Ok, but Aja told me the 12g is converted to 4x3g with their 12GM and the audio is embedded into SDI 1, so you should need only two SDI to Audio (mini converter not Teranex) to output 8 Audio channels, no?

Hi Robin,

in theory yes. You are talking about the SDI to Audio 4K mini converters right?
We went with the Teranex converters because we wanted to have an all 12G SDI pipeline, only to encounter a lot of issues between Decklinks, Teranex and BMD converters. In the end we bought a lot of 12GMs just to get a working 4K DCI signal from our Decklinks, so now you can learn from our mistakes.

I'ts more Blackmagic's mistakes than yours.

Ok, I undertand. Someone lent me a SDI to HDMI 4K this morning to test if I can de-embedded the audio from a 6g-SDI. And it works.

Ultrastudio 4k mini -> SDI to HDMI 4k -> output to balance audio.

In 4K YUV 25p, no problem... but in 4K RGB (even at 25p) the signal is probably 12G-SDI and converters can't receive the signal.

Blackmagic should take more time to fix 100% of their products before to sell them. And I'm sur if they create a SDI 12G to DB25 connector they would sell it easylly.

Best

Robin

PS : sorry for my english, I normally speak french

QuickSand wrote:Hey Robin,

we use the AJA device just to "flatten" the 12G SDI from a Decklink output and then push the signal through 3x Teranex Mini SDI to Audio 12G. Each Teranex Box de-embedds 2 channels of audio, so for our 5.1 monitoring we need 3 in total.

Sounds sooo convoluted.
Surely there are better de-embedders, like AJA 12G-SDI 8-Channel AES Audio Embedder/Disembedder (995$)

Splitting 5.1 into 3 different routes is already asking for problems (eg. sync-wise) on top of whole "complication" of the setup.

Hey Robin,

I am totally with you and have actual open tickets with BMD support (which takes time as you may know) for various issues with their 12G products. It's unfortunate that you encounter this many issues when in the past SDI was a pretty straight forward process. But the bigger the facility, the more problems occur I guess.

@Andrew: what do I want with an AES de-embedder if I need analog audio out?

Analog?

https://www.rcblogic.co.uk/product/soni ... ue-outputs

If you have AJA 12GM you can convert 12G into 4x3G and then take audio from one of those 3G signals (video bit is irrelevant here) and feed it to the box from the link above.

Our audio processor has only analog audio in and no free AES inputs left.

Why do you recommend us products? We have a working setup.

QuickSand wrote:Hey Robin,

we use the AJA device just to "flatten" the 12G SDI from a Decklink output and then push the signal through 3x Teranex Mini SDI to Audio 12G. Each Teranex Box de-embedds 2 channels of audio, so for our 5.1 monitoring we need 3 in total.

This you mean ? I thought you are after something simpler.

How do you guarantee sync between channels if you split them into 3 separate routes? Is output from this 3 Teranex boxes synced between each other? I would not count on it for 100%.

It works for us in our infrastructure, I am just helping Robin to give him some options. We reclock the analog audio via the audio processor, so that is not a problem.

If 1 Teranex box processes signal for eg. 1 frame shorter/longer than others you will never know once it hits analog signal (you can't auto re-sync analog signal as there is no reference anymore).
If it works for you maybe differences are not bigger than eg. 1 frame so you'll never really see it. Besides it's going to be hard to tell 1-2 frames offset if this happens only on 2 of to 6 channels.
Setup sounds convoluted at least

Then it should be no problem for you to fix our setup right? How would you do it?

Already shown 1 way. Instead of convoluted 3x Teranex boxes you just use 8 channels de-embdder, so all stays in one audio route and you have no de-sync between channels. Still doesn't mean you won't have de-sync agains video, but this is different problem and maybe you can compensate for it. Having 3x2 channels which are 5.1 audio drifting between each other is bad for sure and hard to notice. If you're talking about proper monitoring then this is rather unacceptable solution.

https://www.rcblogic.co.uk/product/soni ... ue-outputs

Ah okay, so this 3G de-embedder perfectly works with our 12G Signal?

No, it doesn't support 12G.
You feed it with 3G signal (one which has audio) from AJA 12GM converter (video bit is irrelevant here).

Also - this is cheaper than AJA for converting 12G to 4x3G and it has few extra bits:
https://www.decimator.com/Products/Mini ... CROSS.html

Hello,

So I decided to go like this:

Ultrastudio 4K mini
To
SDI to Audio 4K mini converter (L,R,C,LFE)
To loop to
SDI to HDMI 4K mini converter (Ls,Rs)

This solution is 6G compatible for a reasonable price

For a 12G just add the Decimator 12g to 4x3g.

Robin

You are making same mistake- splitting 5.1 channels into 2 separate routes.
Proper way here is to de-embed all 6 channels over 1 device/route. Any splitting here (with extra looping main signal over another converter) is simply bad way.

If you want to do it cheaply then you can start with boxes like this:
https://www.amazon.com/AllAboutAdapters ... B07J2VZ8DL

take HDMI out of UltraStudio 4K Mini and feed into it. I assume there are more pro boxes like this which will be still cheaper than any SDI route. You most likely still face de-sync with video and need to compensate for it somehow, but at least all your 5.1 channels are in sync between each other.

Hey Robin,

that sounds good! The SDI to Audio 4K accepts all your outputs from the Ultrastudio 4K? Maybe you add the 12GM to pipe a single signal to an 3G 5.1 de-embedder?

@Andrew: probably a good solution but in the earlier years we scrapped those Teranex units together from various setups and didn't had to spend any money. As long as this setup works well enough I wouldn't spend the money on it. Would be another story if one would build it from scratch today.

The SDI loop is processed before de-embedding. So I assume both mini converter de-embed at the same speed. I launched a beep sync and didn’t notice any delay.

I should have precise I’m not sound mixer but colorist. The idea behind this is to have a 5.1 monitoring.

QuickSand wrote:@Andrew: probably a good solution but in the earlier years we scrapped those Teranex units together from various setups and didn't had to spend any money. As long as this setup works well enough I wouldn't spend the money on it. Would be another story if one would build it from scratch today.

I understand this.

QuickSand wrote:Hey Robin,

that sounds good! The SDI to Audio 4K accepts all your outputs from the Ultrastudio 4K? Maybe you add the 12GM to pipe a single signal to an 3G 5.1 de-embedder?.

No... the 4K dci RGB 25p doesn’t work... I think 4K dci RGB uses 12G...

Robin Erard wrote:The SDI loop is processed before de-embedding. So I assume both mini converter de-embed at the same speed. I launched a beep sync and didn’t notice any delay.

Yes, but this is still doesn't prove much in whole system. If we talk about 5.1 audio and proper monitoring then sync between channels needs to be perfect or your phases coherency is gone.

What about doing this way:

If you want to do it cheaply then you can start with boxes like this:
https://www.amazon.com/AllAboutAdapters ... B07J2VZ8DL

take HDMI out of UltraStudio 4K Mini and feed into it. I assume there are more pro boxes like this which will be still cheaper than any SDI route. You most likely still face de-sync with video and need to compensate for it somehow, but at least all your 5.1 channels are in sync between each other.

Robin Erard wrote:

QuickSand wrote:Hey Robin,

that sounds good! The SDI to Audio 4K accepts all your outputs from the Ultrastudio 4K? Maybe you add the 12GM to pipe a single signal to an 3G 5.1 de-embedder?.

No... the 4K dci RGB 25p doesn’t work... I think 4K dci RGB uses 12G...

Okay, I don't know how often you have to use that mode, but in that case me and Andrew both provided solutions, so I think you are in the clear!