Neither CUDA nor NVDEC will enable on Windows

[Doofussy2]

Latest Git build, but it's been this way for as long as I've had my GTX 1050 (a few months)
Windows 10

Reproduction steps
Using hwdec=cuda or hwdec=nvdec in the mpv.conf, results in software decoding. But cuda-copy and nvdec-copy, work

Expected behavior
Hardware decoding

Portable mpv log.txt

I've also reported this Nvidia, in case it's a driver issue.

[morphological]

Encoding works fine when ffmpeg is compiled with --enable-nvenc and --enable-cuvid
Gotta install the headers first though: lutris/ffmpeg-nvenc#22
Guide over here: https://github.com/mpv-player/mpv-build

  --ovc=h264_nvenc   NVIDIA NVENC H.264 encoder
  --ovc=nvenc        NVIDIA NVENC H.264 encoder
  --ovc=nvenc_h264   NVIDIA NVENC H.264 encoder
  --ovc=nvenc_hevc   NVIDIA NVENC hevc encoder
  --ovc=hevc_nvenc   NVIDIA NVENC hevc encoder

Decoding with nvenc also works btw, you just need to install the SDK.

[Doofussy2]

Thanks for responding, but this is confusing. First, I'm not encoding anything. Second, the mpv manual says to use hwdec=cuda with vo=gpu. This is the method used for all hwdec, in the manual. It works with other decoders but not cuda or nvdec. Has something changed that hasn't been updated in the manual?

[aufkrawall]

cuda & nvdec only work with --gpu-api=opengl

[Doofussy2]

I believe I tried that, with no success. I will retest, when I get a chance.

Thank you.

[Doofussy2]

Just tested with gpu-api=opengl with cuda and nvdec. No change. They will not enable. Other guys I've talked to online, also can't get them to enable.

[aufkrawall]

You're right, doesn't work here either with @shinchiro 's build while it works with self compiled build on Linux.

[Doofussy2]

Still not working in the 2018-07-14 build

[saildata]

Works here. https://i.imgur.com/bOWgOJb.jpg

OS: Arch Linux 4.17.5, 1080-Ti 11G

• Installed ffnvcodec-headers as others have mentioned.
• Added --enable-nvenc to ffmpeg build options.

mpv --version

mpv 0.28.0-633-g351c083487 Copyright © 2000-2018 mpv/MPlayer/mplayer2 projects
 built on UNKNOWN
ffmpeg library versions:
   libavutil       56.18.102
   libavcodec      58.21.105
   libavformat     58.17.101
   libswscale      5.2.100
   libavfilter     7.25.100
   libswresample   3.2.100
ffmpeg version: N-91473-gc5329d64b1

MPV stdout:

(+) Video --vid=1 (*) (vp9 3840x2160 60.000fps)
 (+) Audio --aid=1 --alang=eng (*) (opus 2ch 48000Hz)
Using hardware decoding (nvdec).
AO: [pulse] 48000Hz stereo 2ch float
VO: [gpu] 3840x2160 cuda[nv12]

I also have vo=gpu hwdec=auto gpu-api=auto
it was not necessary to have gpu-api=opengl for mine. Just for fun, I ran the same video in 'benchmark' mode:

[bench]
hwdec=cuda
scale=ewa_lanczossharp
cscale=ewa_lanczossharp
vd-lavc-threads=32
audio=no
untimed=yes
video-sync=display-desync
vulkan-swap-mode=immediate
opengl-swapinterval=0
opengl-pbo
osd-msg1="FPS: ${estimated-display-fps}"

and got around 250fps on 3840*2160 UHD. All seems to be fine on this end. I think it just depends on your build and having the right libraries installed.
https://i.imgur.com/YIaezFe.jpg

[shinchiro]

Uh, I'll explicitly add --enable-nvdec when configuring ffmpeg if that will change anything. It's supposed to be on (autodetect) by default before.

[saildata]

I think I also used --enable-cuvid or --enable-cuda I can't remember which. Sorry I built in /tmp and deleted my makefiles.

[Doofussy2]

@shinchiro , unfortunately, cuda nor nvdec are still not enabling in your latest build :(

[shinchiro]

[vo/gpu] Loading hwdec driver 'cuda-nvdec'
Cannot load cuInit
[vo/gpu/cuda-nvdec] Failed to load CUDA symbols
[vo/gpu] Loading failed.
[vd] Could not create device.

Just realized, it's always enable before. I believe you need to download/install cuda toolkit (~1.5GB) to use it.

[Doofussy2]

So to use nvdec or cuda, the cuda toolkit needs to be installed? The manual needs to be amended, to inform the user to do this. As is, the manual states that you can simply enable it.

https://mpv.io/manual/stable/#options-hwdec

cuda: requires --vo=gpu (Any platform CUDA is available)
nvdec: requires --vo=gpu (Any platform CUDA is available)

[Doofussy2]

@shinchiro . I installed it, no change. It still doesn't enable.

[aufkrawall]

I don't think that something cuda/nvdec related is missing, as -copy modes work. It rather seems to me that something interop related doesn't work with Windows builds.