Unexpected behaviour when playing interlaced media


Hi, I have CS ver 2.2 and Blackmagic DeckLink Duo 2 set to 1080i50.
I have 1080i5000 video-mode in casparcg.config file.

When I am trying to play a 30 frames long clip (with fast horizontal motion - custom wipe for TV broadcast) usually the video is jerky. BUT NO EVERYTIME… Playing is absolut clear in about three out of ten attempts.
I don’t understand how it is possible.
Frame rate of the clip is 25 fps, Upper field first.



From what you write it’s not possible to see the problem. It could be a performance problem of your PC or anything else. Du you see a difference, when you load the clip before playing (in the official client F3 loads the clip and F2 plays it)?


I don’t think it’s a performance issue. My PC has good parameters (6 core Xeon, 3,6 GHz, NVidia P2000, 32 GB RAM, SSD disks etc.)
I have no problem with progressive clips. I have tried to play three clips in different layers at once without any issues.
Jerking in interlaced clip looks likewise wrong manipulation with fields.

I see this difference BUT just Yesterday. When I send LOADBG command before PLAY (F3, F2), interlaced clip plays fine in about 19 out of 20 attempts. Today without any changes in caspar,config, hw etc. the result is wrong in both cases (only F2 and F3+F2)

It is ablolut inconceivable for me.

Do You have some short interlaced mov clip which plays correct at Your machine?


I think I was experiencing this while doing some testing the other day (in 2.2 or 2.3, don’t remember which). I was using a script to play the same clip (the go1080p25.mp4 sample) every few seconds, and sometimes it would play with what looked like the field order reversed.
I wasn’t sure if my case was down to sluggish performance due to running in debug mode, so was going to do more testing before writing it up


Now I try it on v2.1.8_NRK and everything seems to be OK. Interlaced clip plays smooth every time.
We will see tomorrow :grinning: