Problem Working with Recording of a Zoom call

I recorded a long zoom call with the recorder in zoom, which saved the recording to my c drive as an MP4 (302 MB). I imported the MP4 into a DR project and am finding that playback is unusually slow and choppy in DR 18.6.

There doesn't appear to be a problem with the MP4 . It plays normally in windows media player.

The MP4 has a frame rate of 25. Initially, I didn't revise the frame rate of the timeline I was working with and left it at 24. I switched to a timeline with frame rate of 25, and that helped, but did not fully fix the issue. I am using proxy playback and have set playback resolution to 1/4. That hasn't solved the problem either.

I welcome suggestions.

Solved: I neglected to generate optimized media. After doing that, I'm getting excellent performance.

If you happen to read this and understand why I needed to generate optimized media, I'm interested in understanding that better.

Which codec exactly and is it constant frame rate or variable?
If you don’t know, get MediaInfo.

Thanks Uli. I'm new to mediainfo. Is this the info you are looking for?

ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L5.1
Format settings : CABAC / 5 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 5 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 h 43 min
Bit rate : 279 kb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.001
Stream size : 207 MiB (68%)
Title : H.264/AVC video
Encoded date : 2024-04-30 09:40:31 UTC
Tagged date : 2024-04-30 09:40:31 UTC
Color range : Limited
Color primaries : BT.601 PAL
Transfer characteristics : BT.709
Matrix coefficients : BT.470 System B/G
Codec configuration box : avcC

Yes. At least it’s constant frame rate, good! Your machine may not have the hardware for decoding that AVC level in UHD. So, optimized media are a solution, as would be transcoding to an easier codec, like DNxHR or CineForm. Either method needs more space.
Playability in a simple player is not the same as use in an NLE.