how can i use Intel hardware acceleration?

[LOUYWEI]

I compiled ffmpeg and enabled qsv. I tested ffmpeg through the CLI and confirmed that it can encode and decode videos using the h264_qsv codec, and av.codecs_available also can see h264_qsv. However, when using pyav, it encounters an error. I would like to ask if pyav currently does not support qsv hardware codec and how can i use it.
av.error.UnknownError: [Errno 1313558101] Unknown error occurred: 'avcodec_open2(h264_qsv)'; last error log: [h264_qsv] Error creating a MFX session: -9.

but I have conducted such a test ffmpeg -hwaccel qsv -c:v h264_qsv -i input.mp4 -c:v h264_qsv -f mp4 out.mp4and can successfully write to an mp4 file.iHD can also be viewed through vainfo.

My pyav version is 15.0.0, and the ffmpeg version I compiled is 7.1.1. I also installed onevpl and libvpl according to the version correspondence,I also checked the architecture correspondence of Intel's media_deriver and selected the supported version. and the results of av.library_versionsand ffmpeg -version can also correspond to each other.

Trying display: wayland
error: XDG_RUNTIME_DIR not set in the environment.
Trying display: drm
libva info: VA-API version 1.22.0
libva info: User environment variable requested driver 'iHD'
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_22
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.22 (libva 2.22.0)
vainfo: Driver version: Intel iHD driver for Intel(R) Gen Graphics - 25.2.6 ()
vainfo: Supported profile and entrypoints

ffmpeg version 7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
  built with gcc 11 (Ubuntu 11.4.0-1ubuntu1~22.04)
  configuration: --prefix=/opt/ffmpeg-7.1.1 --enable-shared --disable-static --enable-gpl --enable-nonfree --enable-version3 --enable-vaapi --enable-libvpl --enable-libdrm --enable-libx264 --enable-libx265 --enable-libvpx --enable-libaom --enable-libdav1d --enable-libfdk-aac --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libass --enable-libfreetype --enable-libfontconfig --enable-libfribidi --enable-libwebp --enable-openssl --enable-protocol=rtsp --enable-protocol=rtsps
  libavutil      59. 39.100 / 59. 39.100
  libavcodec     61. 19.101 / 61. 19.101
  libavformat    61.  7.100 / 61.  7.100
  libavdevice    61.  3.100 / 61.  3.100
  libavfilter    10.  4.100 / 10.  4.100
  libswscale      8.  3.100 /  8.  3.100
  libswresample   5.  3.100 /  5.  3.100
  libpostproc    58.  3.100 / 58.  3.100
Hardware acceleration methods:
vdpau
vaapi
qsv
drm

{'libavutil': (59, 39, 100), 'libavcodec': (61, 19, 101), 'libavformat': (61, 7, 100), 'libavdevice': (61, 3, 100), 'libavfilter': (10, 4, 100), 'libswscale': (8, 3, 100), 'libswresample': (5, 3, 100)}