How to "play" a Composure composite video?


I’m new to UE4 (and game engines more generally). I successfully stepped through this compositing tutorial., but I can’t figure out how to actually view the finished composited video. I can preview by right clicking root node in the Composure panel, but that just seems to show the correctly-composited first frame of the video with CG components in the foreground and background. How do I actually play the composited video?

Sorry for the newbie question, but I guess the tutorial assumes one already knows that basic info. Thanks for any guidance!

Ok, not positive about this but…I think you have to record and play the unreal window with an external tool like OBS. If everything you are doing is CG, you can record it with sequencer which records the animation info of all the CG objects and can play them back. I think sequencer can also render out to images or ProRes video also. I’m not sure what will happen if you are doing a composite with live video and try to do a prores recording with sequencer, I haven’t had a chance to try that yet.

Some people get a BlackMagic or Aja card that supports output and then use an external recorder like a Atomos Ninja V or another PC to record it.

I’m looking into other recording options, if I come up with something good I’ll post it.

Thanks for the response, @Greg.Corson. The tutorial I referenced suggests that output is optional. The last section states…

…which implies that the resulting composite can be previewed in the editor, but I sure can’t figure out how. I don’t see why it wouldn’t be possible, but it’s certainly not obvious to me. I’m on a Mac, BTW, so some of the options you mentioned might not be applicable.

Thanks again.

OBS is available on Mac, so I assume it would work for recording the screen.

I believe what the quote from the tutorial means is, if you hit play in the editor you will see your composite of live video and CG on the editor screen in real time. If you are using a movie instead of a live camera, you may have to add some blueprint code to start it playing.

So far, I have only used OBS to record a window or full-screen output of unreal. All my setups have a live camera/greenscreen and CG virtual set…I haven’t tried recording using sequencer yet.

I’ve already got a screen recording utility. The issue is that I couldn’t play the composited video. I’ve since realized that I simply needed to play it from the MediaPlayer element. I guess I’m just accustomed to using “higher level” tools. Currently, there’s a File Media Source, a Media Player referencing it, a Media Texture referencing the Media Player, a Material which composites the Composure elements. I’m slowly grokking UE4, but it’s taking awhile along with some project-based learning.

Unfortunately, I just updated to UE 4.24.1, and now the video file fails to open. The output log says…

LogAvfMedia: Warning: Failed to load video tracks. [The operation couldn’t be completed. (OSStatus error -12203.)]

I have no idea how to proceed now.

Ok, I just selected the file again, and it’s now working. However, the MediaPlayer doesn’t remember the file. I have to keep selecting it from the Media Library every time I want to preview it. How do I permanently associate the movie file with the MediaPlayer element? I suspect there’s something I just don’t understand.