Flash frame/glitch at start of video playback

[zinger5]

Describe the bug
I've been testing some video playback with files encoded in a variety of codecs and for many of them I'm getting a flicker/flash frame at the start of playback. This is particularly troublesome as I'm attempting to seamlessly play a loop in some cases or two videos which should seamlessly follow on.

Expected behavior
Oddly, I have no such issue when I play back the same videos using the CasparCG Client and I can create the same issue if I send an AMCP command calling the videos using the SEEK 0 command but calling the same video with CUT 0 plays without any flash frame. Is this a known issue and is there a way of forcing SuperConductor to use the CUT 0 command instead of SEEK 0?

Desktop (please complete the following information):

• OS: Windows 10
• Version 0.11.3 and tested on 0.12.0 alpha 4, both with the same outcome

Additional context
I'm using a 1080p5000 consumer as the output at the moment. Video files were mostly encoded as NotchLC Quicktime MOVs but I've also tested Prores MOVs (422 and 4444) as well as h.264 MP4s and AVI files encoded as Newtek SpeedHQ. All give them same error.

[nytamin]

Hi!
Thanks for the bug report!

I haven't seen that flash frame issue before, neither in Superconductor nor in Sofie Automation (they use the same playout engine, TSR).

Which version of CasparCG are you using?
Do you have the same issue in a newer/older CasparCG version?

[zinger5]

Thanks for the reply - I've been using v2.4.0-stable and I've just tested with both v2.4.0-stable and v2.3.3-lts-stable which both reproduce the same issue. (v2.3.3 LTS can't read the NotchLC files due to the older FFMPEG version but Prores and MP4 files give the same glitch).

In case it's helpful to share any other specs of this machine:

CPU: Intel i9-9900K
OS: Windows 10.0.19045 Build 19045
RAM: 64GB
GPU: Nividia RTX 2070
Nvidia driver: 565.90

I'm going to test on another device later as well so will report back if it's machine specific.

Thanks!

[zinger5]

Ok - so I've tested the same files on another machine (a Windows 11 laptop) and it displays the same issue, so it seems to be fairly consistent for me with these files. Any thoughts on workarounds or whether it's possible to use CUT instead of SEEK?

[nytamin]

Thanks for taking the time!

The CUT argument does not exist in the AMCP protocol as far as I'm aware, so if you send that it's probably just ignored by Caspar. The ones that do exist are SEEK, IN and LENGTH.

To aid in further troubleshooting, would you be able to provide a sample file that flash for you?

Also, could you clarify what the "flashing" mean? Is it like a single white frame, or something else?

Another thing that could provide some insight is if you test what happens if you play a file using SEEK 1, or SEEK 10, do you still get the "flash"?

Thanks!