Time Syncing Video Streams?

[mcentrye]

Is there a way to time sync two video streams? I.E. 2 Adobe Flash encoded videos from 2 cameras. Or any other encoder that would allow syncing on the receiving end.

Something kind of like what ProVideoSync does for recorded video.

Thanks,
Chris

[petereit]

Nothing I'm aware of. What is the issue you're trying to resolve?

[mcentrye]

Originally Posted by petereit

Nothing I'm aware of. What is the issue you're trying to resolve?

Just investigating. We're thinking trying to stream with a media server to a remote location. Streaming two shots would be interesting. Maybe a stage wide shot and an IMAG shot. Just wondering if we did that, would there be a way to keep the feeds synced with one another. I've never heard of anything, but figure it couldn't hurt to ask.

Chris

[dmerchen]

Interesting idea, sounds like you'd need timecode information from each of the devices and tie them to some sort of global clock.

Here's another idea, place the switching hardware on one end, and only send one stream, focusing on being able to remotely control the switcher. Something like the BlackMagic ATEM switchers can be controlled over the network, you could use VPN to tunnel back to the streaming location; of course this way to introduce a concern of latency.

Something slightly more unorthodox you might look at would be a bit like the inverse of a matrox head, so send both video streams in one feed, ensuring their all in sync, then breaking them apart later.

I realize these are rather unrealistic drables, but some outside the box solutions if you get stuck.

What sort of bandwidth do you have between the locations, and latency?

[petereit]

Typically, encoding for streaming is the last step in the signal chain. In most multiple-camera setups, you would run your uncompressed camera signals to a video switcher. The output from the switcher would go to a computer or other dedicated hardware device for compression and encoding for streaming. So the audio/video sync all occurs before encoding.

[mcentrye]

I didn't describe the intentions very well. The reason for two streams would be to have both a stage wide static shot and a close shot that comes from the switcher. They'll be shown on separate screens. So other than sharing bandwidth, the signal paths are completely separate. The timing is the where I'm most concerned.

Merging the two signals on the source side and seperating on the target side with a Matrox Dual Head is an interesting idea. I used that with ProPresenter. How do you merge the two signals?

[petereit]

Aha! I get it now. You probably want to look at Renewed Vision's Pro Video Sync.

[mcentrye]

I've looked at Pro Video Sync and it looks like an awesome product, however it is for syncing saved video files. It doesn't work with streaming.

Seems like this wouldn't be that odd of a situation, but I'm having a hard time finding much about it.

[tdangelo]

Originally Posted by mcentrye

I've looked at Pro Video Sync and it looks like an awesome product, however it is for syncing saved video files. It doesn't work with streaming.

Seems like this wouldn't be that odd of a situation, but I'm having a hard time finding much about it.

Mcentrye,

You may be able to use some technology intended for 3D in a different manner to get you what you want.

When we shoot 3D we start with two HD signals. One for the left eye, one for the right eye. This is typically called Stereoscopic 3D, or S3D. Once the left eye and right eye images are created (live or in post) they then get "muxed" together into one 1.5Gbps HD signal for distribution and viewing on consumer & prosumer monitors.

Well, what if instead of having left eye, right eye images you had your screen #1, screen #2 content. And what if that was muxed together before web encoding and the demuxed back to two HD signals for two screens at your destination. Seems like that would solve the two stream sync issue because you would only be streaming one signal!

That said (as I have posted in other threads) I think streaming live to a church for "live" projection is generally a bad idea. Muxing (and demuxing the signals) will only make the quality that much worse ... so I have my concerns about your plan even if only one signal ...

But with that said if you want to send two signals across the internet and have them arrive in perfect sync the only way I can think of doing it is to combine them into one signal before encoding for the stream.

[sempei13]

So they're being shot at the same time and transported over the internet? Are you getting latency in one or the other primarily? Is one going to a third party first and then to the other site?

What about something like a Tivo? If one is primarily slower than the other, couldn't you put the faster one through a DVR to delay it long enough to sync it up with the second one?

If network delays cause the slower one to swap from time to time, I don't know of much else you could do. If it only changes after each service, you could have two dvrs, sync whichever is faster with the slower one, making sure a test shot is synced before service begins.

Not the "right way", but it might just work. I bet if you could keep the sync within a couple of frames, no one would notice (especially on different shots).

Paul