PT Video plays back faster than audio

[JakeHa]

Hi there,

First of all, I'm new to this forum. I apologize if this has already been covered - I could not find this exact issue when I searched through the previous posts.

I saw the sticky regarding the Avid webinar from 2016 and I am currently watching it.

Wanted to post this question in case there is an easy solution we are overlooking...

SYSTEM INFO:
2010 Mac Pro
3.46GHz 12-Core Xeon X5690
48GB Ram
8GB XFX Radeon RX 580 GPU
System Drive: 1TB SSD
Record Drive: 2TB Mercury Elite Pro SSD
Pro Tools 2019.10 Ultimate
HD Native PCIe card w/ 32ch RedNet Dante interface
- Currently using (2) Displayport outputs from the Radeon for (2) computer monitors for Pro Tools
- Additional Video card for (2) PT VIDEO TVs: Blackmagic Intensity Pro 4K
- Using the HDMI output from the Intensity Pro 4K into the HDMI input of an HDMI to SDI 6G Mini Converter (dip switches set to "Force to HD"), out both outputs via BNC of 75' to each of the (2) TV's and converted back to HDMI via Blackmagic UpDownCross MiniConverters (dip switches set to 1080p 60fps). One TV is in tracking room; one tv is in the control room.
For PT Word Clock, we are using an Avid HD Sync Master Clock.

Blackmagic Desktop Video Software: Version 10.11.4

PROBLEM:
When we import a video file that has a frame rate of 23.976, we experience the video playing back much quicker than the audio (approximately 30% faster).

Notes:
Converting the same video file to 24 fps and re-importing seems to completely solve the issue. Pro Tools is happy with any 24 fps footage. At this point, our necessary workflow has been to convert any 23.976 video we receive to 24 fps and that works fine for in-studio sessions.

Question:
We commonly do ADR sessions using Source Connect with other studios and we have not yet attempted a session with this new workaround and I am concerned this may affect how they receive timecode on their end when we are sending... Should I be worried? Very worried? Or does the 24fps only affect our native video playback and not the actual timecode of the PT session?

BTW this is all a new issue to us because we recently updated to PT 2019.10 Ultimate from PT 10 HD. We have been using an Avid Mojo as our video output up until now and that doesn't work with the newest version of Pro Tools.

Attached is a screenshot of our video track and session settings. Please let me know if you have any thoughts or solutions.

I started diving down a rabbit hole of threads about tri-level sync and it's honestly way over my head. I really hope that isn't necessary, but obviously I need to learn and figure it out.

Thanks,

Jake

[Vedat]

First of all. Forget everything about reliable video playback that you had on PT10 HD. Those days are gone.

Second, if your session is happily playing the 24fps video file, I don't think you need to worry too much since it's just for ADR (small segments). If your session is 23.976, the other end will receive your LTC as 23.976 and lock up just fine.

[JakeHa]

Thanks for the reply!

To update this particular situation, the partner studio was concerned about us having to convert to 24 fps and sent the video with a different codec.

Original file that was sent was H.264 (the file that sped up on playback)

New file is JPEG movie and plays back fine at 23.97 fps.

The Avid webinar was extremely helpful to watch. My main takeaways from it were:
- Allow ample time for video file testing/conversion while prepping every session to ensure reliable performance during the session. This is part of our normal workflow now (more than it was before).
- Files with little to no compression are likely to playback smoother in Pro Tools because the video engine does not have to decode (or has less to decode) during playback. Only trade-off here is file size increases.
- Avoid resizing the video window to a size other than the standard zooms to avoid unnecessary rendering during playback.
- Certain codecs work better with the Avid video engine than others... H.264 is apparently not a reliable codec, but works sometimes. Preferred codecs are DNxHD/HR and Apple ProRes.