I'm using Stage Traxx to send MIDI events to trigger the start of a video in Stage Cue.

The challenge I'm facing is that the actual video playback start time can vary by up to 300ms and for this particular project I'm working on, I need a much greater degree of consistency so that the video (from SC) and audio (from ST) are more reasonably in sync. I'm not expecting a SMPTE time locked level of sync, but the variability I'm seeing is making this solution unviable at the moment.

I'm hoping to get any feedback on ways I can improve this, or if Peter sees any coding opportunities that will improve this in the SC app.

Hardware/software:
ST4 2029 on a 9th Gen iPad, iOS 26.1.0
SC 1.0.5 on a 5th Gen iPad, iOS 16.7.12 (also tested on a 9th Gen iPad, iOS 26.1.0 but seeing identical results)
The videos in Stage Cue are all 720p HEVC MP4 files. Videos are between 3-5 mins long and file sizes range from 90MB-180MB.

Each song has an associated video of the same length.
At the start of each song, I have a MIDI command to trigger the start of the associated video in SC.

To sync the video in SC to the audio in ST, I had the person creating the videos using the combined backing track+click that IU have loaded into ST as the audio 'base' for the video. So they have ensured that all the key video elements that need to be in sync with the audio, are in sync.
I can then playback the song in ST (hearing the click track) AND hear the exact same thing from Stage Cue (because the exact same audio is on the video), and nudge the MIDI start trigger event to deal with latency. Once I stop hearing 'flamming' on the click, I know I'm close enough for the needs of the project.

That's when I noticed the inconsistency problem.
The sync timing would be perfect 1 time, and then out by half a beat the next, then out by 1/16 beat the next, then perfect the next, and so on.

While I know that reducing file sizes will help improve the video load time (and thus video start consistency), I'm already squeezing blood from a stone on that front. We started at 1080p AVC encoded files that were twice the size. Where I'm at now (720p HEVC MP4 files) is still delivering the required video quality, and I'm not sure there is much more I can squeeze out of video format aside from dropping to 480p which might be a bridge too far. I'm going to get them to try some 'lower quality' setting in the encoder (still at 720p) which will reduce file size a bit more while hopefully still having good enough quality video.

I've been curious about the performance of the Network MIDI Session that SC establishes with the iPad running ST. It always seems very slow to detect when I first set it up. What is the expected latency of this method of MIDI connection? Would bypassing this and going with a CME WIDI solution likely make any difference?

Looking at Stage Cue itself, and I know there may be limited desire for any large changes to it right now with ST4 beta in full swing, but could it be built with specific ST integration and dedicated 'wireless network tunnel' (I'm assuming the existing Network MIDI sessions is an native iOS thing?) that has lower latency and greater consistency of MIDI communication?

Or am I looking at the wrong part of the solution for potential performance improvements? Is the area more likely to be creating variability the way SC loads and plays the video AFTER it receives the MIDI Start Playback trigger? Would having the ability to select a video to 'play next' which then makes SC load it into memory and into the player ready to start once it receives the Start Playback command make a difference?

Or, is SC simply not the right solution for this particular project and it's needs for pretty tight and consistent video sync to the audio backing tracks in ST? If so, does anyone have any recommendations? Keeping in mind that I have backing tracks, lyrics, MIDI events coming out of Stage Traxx and don't really want to pick up and move all that into another solution simply because that solution has integrated video playback alongside audio/lyrics/MIDI/etc.

Thanks in advance!