Here is the video: https://1drv.ms/u/s!Ao-GP3hGG9a9gvUpL_ZfCTAUrVCXSQ?e=PjLxKU, recorded by the built-in screencast tool of Ubuntu 22.04. The ffmpeg was installed via apt, and here is the output:
$ ffmpeg -y -hwaccel cuda -hwaccel_output_format cuda -c:v vp8_cuvid -i test.webm -an -c:v h264_nvenc test.mp4
ffmpeg version 4.4.2 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10.4.0 (conda-forge gcc 10.4.0-16)
configuration: --prefix=/home/conda/feedstock_root/build_artifacts/ffmpeg_1660921500438/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_plac --cc=/home/conda/feedstock_root/build_artifacts/ffmpeg_1660921500438/_build_env/bin/x86_64-conda-linux-gnu-cc --cxx=/home/conda/feedstock_root/build_artifacts/ffmpeg_1660921500438/_build_env/bin/x86_64-conda-linux-gnu-c++ --nm=/home/conda/feedstock_root/build_artifacts/ffmpeg_1660921500438/_build_env/bin/x86_64-conda-linux-gnu-nm --ar=/home/conda/feedstock_root/build_artifacts/ffmpeg_1660921500438/_build_env/bin/x86_64-conda-linux-gnu-ar --disable-doc --disable-openssl --enable-avresample --enable-demuxer=dash --enable-hardcoded-tables --enable-libfreetype --enable-libfontconfig --enable-libopenh264 --enable-gnutls --enable-libmp3lame --enable-libvpx --enable-pthreads --enable-vaapi --enable-gpl --enable-libx264 --enable-libx265 --enable-libaom --enable-libsvtav1 --enable-libxml2 --enable-pic --enable-shared --disable-static --enable-version3 --enable-zlib --pkg-config=/home/conda/feedstock_root/build_artifacts/ffmpeg_1660921500438/_build_env/bin/pkg-config
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
Input #0, matroska,webm, from 'test.webm':
Metadata:
encoder : GStreamer matroskamux version 1.20.3
creation_time : 2022-10-19T20:04:20.108316Z
Duration: 00:00:10.21, start: 0.000000, bitrate: 10824 kb/s
Stream #0:0(eng): Video: vp8, yuv420p(tv, bt709, progressive), 3840x2400, SAR 1:1 DAR 8:5, 1k tbr, 1k tbn, 1k tbc (default)
Metadata:
title : Video
Stream mapping:
Stream #0:0 -> #0:0 (vp8 (vp8_cuvid) -> h264 (h264_nvenc))
Press [q] to stop, [?] for help
[vp8_cuvid @ 0x55d4f912cf40] ignoring invalid SAR: 0/0
[h264_nvenc @ 0x55d4f912bf80] InitializeEncoder failed: invalid param (8): Invalid Level.
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
Conversion failed!
I am working with CUDA 11.7:
$ nvidia-smi
Wed Oct 19 23:38:52 2022
+---------------------------------------------+
| NVIDIA-SMI 515.65.01 Driver Version: 515.65.01 CUDA Version: 11.7 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|===============================+======================+======================|
| 0 NVIDIA GeForce ... Off | 00000000:01:00.0 Off | N/A |
| N/A 53C P0 9W / N/A | 4MiB / 4096MiB | 0% Default |
| | | N/A |
+-------------------------------+----------------------+----------------------+
+---------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| 0 N/A N/A 3373 G /usr/lib/xorg/Xorg 4MiB |
+---------------------------------------------+
And there is no problem if converting with CPU only, i.e., ffmpeg -y -i test.webm -an test.mp4.
