Wowza Community

Can wowza mix two streams? Server-side video editing

Is it possible to do this:

Take incoming stream A and incoming stream B and mix them together to broadcast A and B

in single stream C.

While scaling A and B sizes to fit to screen of C.

Server-side video editing?

Wowza doesn’t do transcoding, so not really. At some low-level, these kinds of things might be possible, but not for practical purposes.


Wowza Media Server 3 Transcoder does do transcoding but the initial release will not support video overlays.


I’m not sure. I don’t think it’s the right platform to build an editing tool.



It is definitely possible to do all that. It is not simple, but it is typical and straight-forward Wowza/Flash application.

The fundamental starting place for you would be the ServersideModules example that ships with Wowza in the examples folder, and the IDE and its guide:

Also look at the VideoChat example, and here is slightly more involved VideoChat example that shows basic av presence using sharedObjects



If the delay is only client-side in some (slow connection) cases, and the streams are in sync from encoders to Wowza, then you might inject cuepoints with timestamps in each stream, and devise some client-side process for checking and adjusting.

Having said that, I’m really not sure how you would make the adjustment client-side. You can’t pause a live stream so that one will catch up. Maybe you can re-subscribe to one or both if they are out of sync.


Is it possible in client side Flash?

Mixing or editing stream together?

I am interested in something similar as well.

We would be having two venues, and both venues will be streaming live video… The idea is to have one final stream, where A and B are merged…

Do you think it is possible with Flash streaming and Wowza? Venue A starts streaming… at one point they pass on to Venue B (at which point both streams are shown in the same player, so that speaker A, introduces speaker B, and then speaker B from Venue B continues with the rest.

Any ideas on how to display live streams that collaborate from 2 venues are appreciated.

Best regards,


Thanks Richard!

I will definitely look up those examples, start working on it and see what happens.

One more question - I have noticed a number of times that when I stream live video, some clients who don’t have enough bandwidth will be building up delay… at one point lets say 1-2min. delay on a 3 hour event. If I start collaborating with 2 streams at one point (when speaker A introduces speaker B, and the final stream starts eventually showing the stream from venue B), how can I be sure that they are mixed at the proper time? Considering that the delay at the client-side might be different for different clients? Or will they just see that point of collaboration in the stream with their own delay when they get to this point (few minutes later).

I hope what I said above is clear enough :slight_smile:

Best regards,


I don’t know if anyone is still looking for this, but if you don’t want to wait for this feature to show up someplace reasonable (i.e. Wowza) it is possible to do this in DirectShow (I know, ugh!).

You can either modify one of the example filters from MS, or even look at paying for some overlay filters from Leadtools.

However, to do this you have to enter the morass of DirectShow.


My question is can I combine an alpha channel video on top of webcam video to make one final video.

So video A is webcam video (it could be any) and there is alpha channel video B on top. So you can see the video A below the alpha channel of video B.

So I want to turn video A and B into one. A union, not concatenation.

Video A will determine the length of the final video.

Wowza doesn’t do transcoding, so not really.Is it possible in client side Flash?