8k hevc decoding problem (nvidia)

relaxvideo wrote on 8/17/2024, 2:49 PM

In another thread user djrikki2 shared a 8k hevc mov file,
which plays fine in MPC-HC mediaplayer with nvdec decoding,
but in Vegas 22 it does NOT use nvdec, and my cpu can decode only at 0.3 fps :)

Why is that? I tried to remux to .mp4 format ('cos i hate .movs), but no luck, no nvdec in Vegas.

Video parameters are:

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L6.1@High
Codec ID : hvc1
Codec ID/Info : High Efficiency Video Coding
Duration : 46 s 560 ms
Bit rate : 394 Mb/s
Width : 7 680 pixels
Height : 4 320 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 : 10 bits
Bits/(Pixel*Frame) : 0.475
Stream size : 2.14 GiB (99%)
Language : English
Encoded date : UTC 2024-08-17 19:38:21
Tagged date : UTC 2024-08-17 19:38:21
Color range : Full
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : hvcC

My 1660 Ti card can decode 4:2:0 HEVC up to 12 bit and max 8192x8192.
https://developer.nvidia.com/video-codec-sdk

So what's going on in Vegas?

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Comments

john_dennis wrote on 7/8/2025, 2:27 PM

Yes.

Howard-Vigorita wrote on 7/8/2025, 2:31 PM

I just retested more thoroughly with vp22 b250 and the problem doesn't seem to be decoding. I think the issue must be selecting the 1660 as gpu in video prefs. Because when I select an Intel or Amd gpu there, with the 1660 as decoder in i/o, it plays the 8k clip with no freezes in the preview. Lots of freezing, however, when the 1660 is selected as video gpu. When it freezes, "..." is listed as the frame rate. My setup, btw, is a single 4k monitor whose hdmi cable is plugged into the gpu selected in video prefs so it shows up there tagged Optimal.

john_dennis wrote on 7/8/2025, 4:33 PM

@Howard-Vigorita said: "... the problem doesn't seem to be decoding."

There may be some truth to that. Here are my results for the same file converted to Pro Res Proxy. Presumably, it should be easier to decode than HEVC?