Down loaded this file. It crashed V18 (so4 plug immediately), it crashed V17 immediately, V16 asked to download a codec which allowed import. the playback used mxhevcplug.dll but no video picture was displayed. The file would not play correctly in Power DVD player. It did play in POTPLAYER. It also played in VLC player. It did load in Power Director 14 but at low frame rate.

How did you get it into Vegas?

Both of my VP18 & VP17 import the HEVC file normally. Have u tried enable Legacy HEVC decoding?

No I'll give that a try

Now imported into V18, runs at 1.6 fps using mxhevcplug.dll thus no gpu acceleration. going to try proxy files

At preview quarter I get 90fps using i5 3rd gen CPU, 32mb ram. In v17 I get 93fps max. In V16 on preview auto I get 100fps

See if you already have the relevant C0018.MP4.sfvp0 file. Works here (legacy HEVC decoding enabled).

i5-7300, (8GB RAM).

yes its arrived now thanks, interesting that v16 offers the fastest frame rate

At preview quarter I get 90fps using i5 3rd gen CPU, 32mb ram. In v17 I get 93fps max. In V16 on preview auto I get 100fps

btw my project settings is 25FPS

My CPU is Ryzen 5 3600X, RTX2060 GPU & 32GB of RAM

At my desktop the file plays with proxies 100f/s using the legacy MXHEVC encoding in File I/O

but because it changes the better SO4 plug for my own HEVC GOPRO footage I switched that back after this trial.

any HEVC 10-Bit file (from A7Siii) I can get my hands on crashes VP18, 4:2:2 and 4:2:0, nvidia disabled or not.

Would be nice to have a Dev team member chipping in if this is being worked on and will be supported.. My A7Siii is preordered arriving soon and I'm dead keen shooting HEVC 10-Bit 4:2:0 4K, but not if I can't edit it.

BTW, 'Vegas Transfer'.. any news on that?? That was one reason I bought the Pro with is not the Pro Edit ;-)

Tested the file on my system. Legacy decoding ON, GPU acceleration of video processing OFF, 32GB RAM allocated to preview. Plays at 100.0 fps. System in signature.

Downloaded the clip and there were issues. I think it's out of spec for mp4 because the audio stream is pcm. Vegas 17 and 18 crashed on me just clicking on the file in explorer unless legacy decoding for hevc is ON. In which case it loaded and played but gpu decoding was disabled and playback was terrible. I guess v16 is legacy because it had no problem loading the file as is and it's playback performance was equally terrible.

A quick fix is to either copy the streams to a mov container or send them into an mp4 container copying the video stream while converting the audio to aac. Or better yet if possible, set the camera to either save in mov if you want high-res audio or set it to save mp4 with aac audio. Anyway, here are the 2 scripts I ran which are pretty fast since they do not transcode the video stream.

ffmpeg -i C0018.mp4 -c:v copy -c:a copy C0018.mov

ffmpeg -i C0018.mp4 -c:v copy -c:a aac C0018aac.mp4

Was only a partial fix on my Xeon system with an amd 5700xt and no igpu with everything legacy set to OFF and decoding set to amd. There was some gpu activity showing in Task Manager but no decoding. Performance was about 3x better but still not good. The amd gpu apparently doesn't support 100 frames per second. Better luck on my 9900k/Radeon 7 system. That amd gpu didn't do any better but when I set decoding to the Intel igpu I got as high as 75 frames per second playback with lows a little over 50.

I think the more fundamental problem is the frame rate and perhaps also the bit rate... any system would probably have trouble keeping up with 200 mbps off of the disk which probably expands to more than double that before it hits the display. I would suggest reserving frame rates like that for slow motion and knocking them down to 1/4 speed while preserving all the frames (25 fps in this case) before pulling them into a video editor. Fwiw, I shot a 2 hour concert last week with a zcam e2 set to 4k 10-bit hvec 30 fps 80mbps bit rate video, aac audio, and edited in Vegas no problem.