My UHD770 in the i9-13900K doesn't decode it. If I turn off all hardware decoding, the preview performance is so bad I'd probably convert it to Pro Res 4444 anyway.

@zzzzzz9125  Which render template did you use in Davinci Resolve?

@RogerS @john_dennis Thank you for your tests.

Which render template did you use in Davinci Resolve?

@3POINT I don't have DaVinci Resolve Studio and the original project, I downloaded this footage from somewhere else on the Internet. Considering it's a decoding flaw in VEGAS Pro, I think it should be fixed here.

Transcoding is also a possible option, but for me it would be more convenient to decode it directly in VEGAS to avoid taking up extra space.

I said: "I'd probably convert it to Pro Res 4444 anyway."

@3POINT See! I can't count 4s either. It's good that I'm not playing poker.

@zzzzzz9125 

The Case for Conversion

It wouldn't load/import into VP22 b194.on my laptop. Transcoding it and it then played ok in VP 22 b194

I can get VP22 b194 to load the audio only if GPU is disabled in I/O. Disabling GPU in Video acceleration as well as will still only allow audio import.

Same as Roger for me, only V20 opens the file with my default settings. I can get V22 to open it if I turn off all GPU settings and enable legacy decoding (both boxes) and it runs at 2 fps.

Same here, not able to import in it's original format.

@RogerS @john_dennis Thank you for your tests.

Which render template did you use in Davinci Resolve?

@3POINT I don't have DaVinci Resolve Studio and the original project, I downloaded this footage from somewhere else on the Internet. Considering it's a decoding flaw in VEGAS Pro, I think it should be fixed here.

When I export H265 (best quality) out of DR19 with following media info:

General
Complete name                            : L:\R E N D E R S\DR\Timeline 1.mp4
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom (isom/iso2/mp41)
File size                                : 843 MiB
Duration                                 : 30 s 528 ms
Overall bit rate                         : 232 Mb/s
Frame rate                               : 50.000 FPS
Encoded date                             : 2024-11-05 10:34:50 UTC
Tagged date                              : 2024-11-05 10:34:50 UTC
Writing application                      : Blackmagic Design DaVinci Resolve

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main@L5.1@High
Codec ID                                 : hvc1
Codec ID/Info                            : High Efficiency Video Coding
Duration                                 : 30 s 520 ms
Bit rate                                 : 231 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 50.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.558
Stream size                              : 842 MiB (100%)
Encoded date                             : 2024-11-05 10:34:50 UTC
Tagged date                              : 2024-11-05 10:34:50 UTC
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709
Codec configuration box                  : hvcC

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 30 s 528 ms
Bit rate mode                            : Constant
Bit rate                                 : 256 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 954 KiB (0%)
Default                                  : Yes
Alternate group                          : 1
Encoded date                             : 2024-11-05 10:34:50 UTC
Tagged date                              : 2024-11-05 10:34:50 UTC

Other
ID                                       : 3
Type                                     : Time code
Format                                   : QuickTime TC
Duration                                 : 30 s 520 ms
Frame rate                               : 50.000 FPS
Time code of first frame                 : 00:00:00:00
Time code of last frame                  : 00:00:30:25
Time code, stripped                      : Yes
Language                                 : English
Encoded date                             : 2024-11-05 10:34:50 UTC
Tagged date                              : 2024-11-05 10:34:50 UTC

This file plays without issues in VP22B194, means to me nothing wrong with Vegas but probably something wrong with the file you downloaded.

The workflow behind that request is a questionmark (at least for me). Export HDR footage as HEVC with 8bit only, and import it again in Vegas? Hmm.

I can't play it either with gou decoding turned on

Looks like chroma sampling 444 is not implemented in Vegas even though it's supported by the gpu (only tested on nvidia 3080ti here)

http://developer.nvidia.com/video-encode-and-decode-gpu-support-matrix-new#collapseTwo

I was only able to play it on my laptop using vp22 with experimental hevc enabled and IrisXe decoding... but it only played at around 2 fps. I could load it without experimental hevc with IrisXe decoding but preview was blank. Got a strange error screen when I saved the project w/exp-hevc and tried to load it without:

With 3060 decoding, it would not load. Transcoded to ProRes4444 with Shutter encoder and that plays fine at full rate, but clip size is 40x larger.