Video after converted to AVI in VDub is laggy in Sony Vegas

[Water]

When I convert this 300 fps clip into an AVI. I looks fine when I watch it from the Windows Movie Player or whatever but when I drag it into Sony Vegas and watch it from there its really laggy.
Maybe it has to do with the conversion settings I'm using
Here's a screenshot of my conversion settings:

Anyone know a solution to this problem? I'm new to this conversion stuff so I have absolutely no idea what I'm doing lmao

Thanks in advance

[poisondeathray]

I can't see your attachment


Is your 300FPS intended to be played at 300FPS, or for something like slow motion , or something else entirely ?

Most displays in USA refresh at 60 Hz , so you probably only seeing 1/5 of the frames when playing in WMP

What project settings did you use in vegas ?

Where is the source video from ? Why did you convert it to AVI? What are the original specs? and what are the converted AVI specs ? Use mediainfo on them, copy & paste the text view (view=>text) back here

[raffriff42]

Here's the link for anybody that can't see the image
https://gyazo.com/a042bca1ef996323437102ed77aee62f

(in short: x264vfw, CRF 23)

h.264 (x264vfw) is going to be slow to edit unless you add --keyint 15 in the "extra command line" area. This will make seeking much faster.
(I just made a quick check in Vegas, and --keyint 15 made an x264vfw clip respond to dragging the playhead about as quickly as a UT Video clip.)
(EDIT your experience may vary. Windows codec hell and all that.)

BTW while you are editing the command line, add --colormatrix bt709 for proper colors.
Also, CRF 23 is fairly low quality for something that is going to be edited and re-encoded. Try CRF 18.
And zero latency does nothing for you except increase file size. It's for live streaming. Fast Decode might help.
And Virtualdub hack should be checked if (& only if) encoding with VirtualDub.

A lossless codec is best for editing, but h.264 with --keyint 15 should be responsive enough and have a smaller file size.