r/AudioPost • u/Important_Swim7251 • 12d ago

Alignment / Sync Audio/Video sync

I’m streaming picture an audio, using PT audio bridge and Blackmagic Video interface to output picture. Sync is fine. But I wonder if I use a clock with a video interface capable of receiving video ref as well as sending word sync to the audio interface would yield better results?

I know the Avid Sync X allows the best sync in conjunction with an HDX card, but that costs a LOT.

Has anyone tested these scenarios?

4 Upvotes

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7

u/reusablerigbot 12d ago

Even with sync X etc we still frequently test systems/see shifts in video sync offset from project to project.

Test your system with Catch n’ Sync and adjust accordingly.

1

u/Important_Swim7251 12d ago

That’s good to know, thanks. One of my challenges is about outputting a solid stream of video and audio, dead in sync. Catch n sync doesn’t help with that sadly

1

u/reusablerigbot 12d ago

Where are you outputting to?

1

u/Important_Swim7251 12d ago

Evercast

1

u/reusablerigbot 11d ago

And it needs to be output to a second machine vs internal routing with NDI?

3

u/drumstikka 12d ago

There’s no benefit to clocking differently unless you have video peripheral that can accept video reference, an HDX or HD Native hard set as your interface, and a Sync HD or Sync X. Without all 3, you won’t have edge frame sync and won’t see any benefit.

1

u/Important_Swim7251 12d ago

This is the sad conclusion I’m coming to

1

u/drumstikka 11d ago

It’s true unfortunately. People have been begging AVID for a better edge frame sync solution especially since HDX is so unnecessary for many rigs these days. Hopefully they listen.

4

u/Abs0lut_Unit 12d ago

If you're in sync you're fine as you are - vid ref and word clock start becoming more important when you're working across multiple PT rigs and interfaces (ie on a mix stage).

2

u/French_Fries_FTW 12d ago

In my experience it is better with clock ref for me. Each time I would press play, I would get slightly different sync. My clients would notice too. I got a sync hd and a clock generator and it is solid now.

1

u/rappit4 12d ago

Used Avid HD Sync

1

u/cutandcover 12d ago

Having worked with PT and video going back to the original AV Option hardware, that’s the only time I could rely on AV sync in lock all the time. Ever since adding a QT to a timeline has been a thing, this has been a moving target for PT. The best I’ve ever gotten it was by using only ProRes (I-frame), calculating video sync offset with Syncheck. Even then, it’s not always perfect. But that’s the best I’ve been able to do.

1

u/Rihanio 11d ago

I used LiveDeck app on android does an amazing job syncing audio and video

1

u/VE3VNA 8d ago

PT audio bridge doesn't guarantee no drift, it even says it in the IO settings. If you need absolute lock you need a Digidesign IO and a Sync box. Welcome to the fantastic world of spending thousands on Digidesign hardware...

1

u/jfa__ 4d ago

I am obviously biased but Postlink might help (I am the developer). To stream you just send your mix to the plugin and open your link in your browser, everything just works automatically from there with video + audio always in sync. (I'm assuming you want to send the stream to remote people since you are using Evercast).

This works because the plugin generates the video + audio stream itself so the streams are fused from the start, no need for any virtual devices, NDI, screen/window capture etc.

For the receiving end there is a client url which works on any browser on desktop or mobile (except Firefox). There is integrated conferencing as well which you can disable if you don't need that.

The documentation has more details