Blackmagic Forum

Can someone please provide the Latency for all Teranex Minis???

Particularly the:

Blackmagic Design Teranex Mini SDI to HDMI 12G Converter

and the

Blackmagic Design Teranex Mini SDI to HDMI 12G Converter

Thanks for the help!

I have no exact timing.. Also depend if scaling in on or not.. And what resolution / framerate you input.. But somewhere between 2 lines and 3 frames..

The Teranex AV (bigger brother does 3 frames on low latency mode.. )

I have a set up where we're running through 5 teranex mini audio embedders in order to record 14 extra isolated tracks into the PGM SDI (in addition to 1 and 2 which is full mix and embedded by the ATEM).

I'm ending up with almost exactly 5 frames worth of delay. Problem is, we're ALSO recording iso's of the cameras out of AUX, and so those recordings have a timecode and audio sync mismatch of 5 frames when "synced" later, synced by timecode, that is.

Is there a way to delay the rest of the feeds? Any sort of BMD gear than can do this (ideally multiple sources), or just 3rd party stuff I'm seeing?

Thanks,
Weston

So the 5 teranex units are inline behind each other and give you 5 frames delay. Which would make sense for some frame buffering, processing and output again..

Well in the broadcast world there will be line delayers.. Maybe even units that do several lines.. But the up to 3G would be easy.. At 12G would be a challenge at this point.. (i guess you are running 4K based on the choice of teranexes over the Audio to sdi embedders that do 4 channels from a single box.

Yeah that's what I am finding. Tons of 3G options out there, hard to find anything else.

Exactly, the 5 frames of delay is unfortunate but expected.

And correct, I'm looking to keep as much as I can 12G on this setup if possible, with 6G being a bare minimum for the time being.

Thanks for the input,

Weston

Ok got an idea..

If you have a Digitial audio mixer like a Behringer X32 or Midas M32 or Allen & Heath QU16.

Use the Aux busses for the audio embedding. And delay them acordingly to the video delay.. Those digital mixers support time delaying on every output channel.

We have a small delay already set on all the mixer's feeds in order to get the audio and video in sync, actually. That's exactly what we are doing with a newly installed Soundcraft digital board.

The issue isn't that A/V isn't synced, it's that the program record that has 16 audio channels (via embedders) does not sync with the isolated camera records that only have 2 (usable) channels beings they are just aux out of the ATEM and do not run through 5 embedders.

So everything is in sync on all records audio to visual wise... however the iso camera records and the program record can't be synced by timecode in post, because the camera records are getting the AV and t/c signal 5 frames earlier than program is. Similarly, the backup audio record (not as big deal since it's just there for emergencies) which is also t/c jammed, is off 5 frames from the program record for the same reason.

Cheers
W

If you have the Teranex Mini converters daisy chained (embedding different audio channels at each converter), and each Teranex Mini is adding 1 frame of delay, then all of the audio tracks should be out of sync with each other. In particular the audio channels embedded at the last converter in the chain should be delayed less than the audio channels embedded at the first converter in the chain.

If all of the audio channels are in sync with each other, that suggests that the delay is probably coming from elsewhere in the system (perhaps from the camera output).

In terms of timecode, ancillary timecode (embedded in the SDI signal) should be carried through along with the video frames (so that both are kept in sync). If the ancillary time code is stripped out somewhere along the chain and you need to re-embed timecode at a later point, you would need to know how much the video frames have been delayed at the point you are re-embedding the time code.

Keep in mind that LTC timecode is just an audio signal, so you could probably use an analog audio delay unit to delay this signal (I suppose you could even pass it through an audio mixer, although sometimes this leads to undesirable crosstalk, and LTC audio does not sound all that pleasant). Another possibility would be to use a second timecode generator with an offset of a few frames, although when using multiple timecode generators there is a possibility of drift (depending on how accurate they are).

Delay the LTC.. Yes it uses audio. But from research i did, ltc seems to suffer from processing.
But you might take a try to put the LTC into 1 Channel of he digital board. Send it Out to an Aux. Delay that Aux. And feed that Aux to the PGM recorder.
If it works it aint stupid. Until you push PFL on the LTC Channel while your headphone is on high volume