SUMMARY

Spectacle does not record videos on NVIDIA powered hardware on the latest few KDE Linux versions.

STEPS TO REPRODUCE
1. Record a screencast using Spectacle
2. Finish the recording

OBSERVED RESULT

Spectacle creates a file with the correct extension, but that just contains a few bytes of header information and no actual video.

EXPECTED RESULT

A complete video file.

SOFTWARE/OS VERSIONS

Operating System: KDE Linux 2025-12-07
KDE Plasma Version: 6.5.80
KDE Frameworks Version: 6.22.0
Qt Version: 6.10.1
Kernel Version: 6.17.9-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 12 × Intel® Core™ i7-9750H CPU @ 2.60GHz
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 2070 with Max-Q Design

ADDITIONAL INFORMATION

When running from the command line and Spectacle configured to produce a WebM  video, the output is this

 ```
$ spectacle 
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
kpipewire_vaapi_logging: VAAPI: VA-API NVDEC driver [direct backend] in use for device "/dev/dri/renderD128"
[libvpx-vp9 @ 0x7fdf640618c0] v1.15.2
kf.kio.workers.file: copy() QUrl("file:///tmp/Spectacle.QkfELe/Screencast_20251208_121834.webm") to QUrl("file:///home/kde/Videos/Screencasts/Screencast_20251208_121834.webm") mode= -1
qt.multimedia.ffmpeg: Using Qt multimedia with FFmpeg version n8.0.1 GPL version 3 or later
[matroska,webm @ 0x7fdfac001f80] Duplicate element
[matroska,webm @ 0x7fdfac001f80] 0x00 at pos 100 (0x64) invalid as first byte of an EBML number
[matroska,webm @ 0x7fdfac001f80] Duplicate element
[matroska,webm @ 0x7fdfac001f80] 0x00 at pos 167 (0xa7) invalid as first byte of an EBML number
[matroska,webm @ 0x7fdfac001f80] Element at 0x5d ending at 0x1aec0100000066 exceeds containing master element ending at 0x1409
qt.multimedia.ffmpeg.mediadataholder: Could not open media. FFmpeg error description: End of file
```

When configured to record MP4, the output is this:

```
$ spectacle 
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
spectacle: OCR is not available; language selector will remain empty.
kpipewire_vaapi_logging: VAAPI: VA-API NVDEC driver [direct backend] in use for device "/dev/dri/renderD128"
[Parsed_scale_vaapi_1 @ 0x7f04880537c0] Failed to create processing pipeline config: 12 (the requested VAProfile is not supported).
[Parsed_scale_vaapi_1 @ 0x7f04880537c0] Failed to configure output pad on Parsed_scale_vaapi_1
kpipewire_record_logging: Failed configuring filter graph
[AVFilterGraph @ 0x7f0488f50800] No option name near 'limited'
[AVFilterGraph @ 0x7f0488f50800] Error parsing a filter description around: 
[AVFilterGraph @ 0x7f0488f50800] Error parsing filterchain 'pad=ceil(iw/2)*2:ceil(ih/2)*2,scale=format=yuv420p,out_range=limited' around: 
kpipewire_record_logging: Failed creating filter graph
[libx264 @ 0x7f0488054580] -qscale is ignored, -crf is recommended.
[libx264 @ 0x7f0488054580] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x7f0488054580] profile Main, level 6.0, 4:2:0, 8-bit
kf.kio.workers.file: copy() QUrl("file:///tmp/Spectacle.KfPgnr/Screencast_20251208_122013.mp4") to QUrl("file:///home/kde/Videos/Screencasts/Screencast_20251208_122013.mp4") mode= -1
qt.multimedia.ffmpeg: Using Qt multimedia with FFmpeg version n8.0.1 GPL version 3 or later
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/kde/Videos/Screencasts/Screencast_20251208_122013.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf62.3.100
  Duration: N/A, bitrate: N/A
```

I'm not sure this is helpful. I hope it is.