VC-1 videos played with nvdec or vdpau show green screen

[seadra]

mpv Information

mpv v0.39.0 Copyright © 2000-2024 mpv/MPlayer/mplayer2 projects
 built on Nov 27 2024 18:31:26
libplacebo version: v7.349.0
FFmpeg version: n7.1
FFmpeg library versions:
   libavcodec      61.19.100
   libavdevice     61.3.100
   libavfilter     10.4.100
   libavformat     61.7.100
   libavutil       59.39.100
   libswresample   5.3.100
   libswscale      8.3.100

Other Information

- Linux version: Arch Linux
- Kernel Version: Linux desktop 6.6.68-1-lts #1 SMP PREEMPT_DYNAMIC Fri, 27 Dec 2024 15:16:06 +0000 x86_64 GNU/Linux
- GPU Model: 3070
- Mesa/GPU Driver Version: OpenGL version string: 4.6.0 NVIDIA 565.77
- Window Manager and Version: kwin_wayland 6.2.5
- Source of mpv: official Arch Linux mpv package
- Latest known working version:
- Issue started after the following happened:

Reproduction Steps

As reported in issue #4820 (closed without being fixed), playing VC-1 videos with hwdec=nvdec or vdpau causes a green screen to be shown only.
vo=gpu with hwdec=auto-safe and hwdec=auto also results in the same issue, but not specifying hwdec at all fixes the green screen issue.

Expected Behavior

Video to be shown

Actual Behavior

Green screen is shown

Log File

mpv-log.txt

Sample Files

No response

I carefully read all instruction and confirm that I did the following:

• I tested with the latest mpv version to validate that the issue is not already fixed.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

[llyyr]

Probably not a mpv bug, VC-1 hwdec is known to be broken on many GPUs (and is also useless, therefore no real desire to fix). Report to Nvidia if you care I guess

[guidocella]

I had the same issue and saw multiple other users with it who couldn't even understand that hwdec was the cause, which is why I proposed not hardware decoding VC-1 by default in #12407

[ValeZAA]

Nvidia does support VC-1, and on windows with nvdec-copy it works just fine; besides seeking, that causes "BUG in ffmpeg" warnings.

CPUs no longer support it since Intel Arrow Lake.

VC-1 was broken before, but meh #5131

[seadra]

Since it somehow doesn't work on Linux, shouldn't hwdec=auto-safe (and perhaps hwdec=auto as well) disable hardware decoding for VC-1?

Having hwdec somehow on is necessary (for >=4K H.265 and AV1 videos for example), so it would be nice to have a hwdec which turns it on with the exception of some known blacklisted cases, like VC-1 on nvdec on Linux. Based on the documentation, I think hwdec=auto-safe is supposed to do this

--hwdec=<api1,api2,...|no|auto|auto-safe|auto-copy>
Specify the hardware video decoding API that should be used if possible. Whether hardware decoding is actually done depends on the video codec. If hardware decoding is not possible, mpv will fall back on software decoding.

so that part is an mpv issue, no?

[seadra]

As a workaround, I changed my mpv.conf as follows to disable hardware decoding on vc1 only:

vo=gpu
hwdec=nvdec
hwdec-codecs=h264,hevc,vp8,vp9,av1,prores

[amariami]

As a workaround, I changed my mpv.conf as follows to disable hardware decoding on vc1 only:

hwdec-codecs=h264,hevc,vp8,vp9,av1,prores 

--vd=help --hwdec=help that's a lot

[Dudemanguy]

Do we care about hardware decoding VC-1 by default? I'm guessing not really and if so I'd be in favor of just merging #12407 and calling it a day since nvidia is probably never going to fix this. Otherwise, we could design some kind of fancy auto value for hwdec-codecs that changes depending on the hwdec API but I'd rather not go through all that effort.

[kasper93]

I'd be in favor of just merging #12407 and calling it a day

In this case, could we add a warning when hwdec=yes and codec is excluded in hwdec-codecs which would otherwise be used? Probably only if it is at default value. hwdec-codecs is pretty obscure config option and people most likely will never notice why decoding is disabled and at best blame driver/hardware support.

[Dudemanguy]

A warning sounds OK to me in that case.

[philipl]

That's reasonable to me too.

[truexfan81]

not sure about nvidia or intel but amd radeon 7000 series cards don't support hwdec for mpeg2video or vc1

[kasper93]

Since this is a NVIDIA proprietary driver issue on Linux. The only way to resolve this issue is to open support ticket or warranty claim for the product you own. This way the issue can be forwarded to people who actually can fix it. There is nothing we can do on mpv to fix hwdec here.