我正在尝试使用以下命令，使用带有硬件加速的 ffmpeg 对视频进行转码：
sudo ffmpeg -hwaccel vaapi -hwaccel_output_format vaapi \
-vaapi_device /dev/dri/renderD128 -i in.mp4 -codec:v h264_vaapi out.mp4
它立即失败并出现错误：
ffmpeg: i965_encoder.c:1692: intel_enc_hw_context_init: Assertion `encoder_context->mfc_context' failed.
附加信息：
完整ffmpeg输出：
ffmpeg version 4.1.3-1 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-7)
configuration: --prefix=/usr --extra-version=1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 22.100 / 56. 22.100
libavcodec 58. 35.100 / 58. 35.100
libavformat 58. 20.100 / 58. 20.100
libavdevice 58. 5.100 / 58. 5.100
libavfilter 7. 40.101 / 7. 40.101
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 3.100 / 5. 3.100
libswresample 3. 3.100 / 3. 3.100
libpostproc 55. 3.100 / 55. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'in.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.20.100
Duration: 00:38:59.14, start: 0.000000, bitrate: 9133 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 8999 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
Metadata:
handler_name : SoundHandler
File 'out.mp4' already exists. Overwrite ? [y/N] y
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> h264 (h264_vaapi))
Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
ffmpeg: i965_encoder.c:1692: intel_enc_hw_context_init: Assertion `encoder_context->mfc_context' failed.
zsh: abort sudo ffmpeg -hwaccel vaapi -hwaccel_output_format vaapi -vaapi_device -i
vainfo输出：
error: XDG_RUNTIME_DIR not set in the environment.
error: can't connect to X server!
libva info: VA-API version 1.5.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_1_4
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.5 (libva 2.4.0)
vainfo: Driver version: Intel i965 driver for Intel(R) Coffee Lake - 2.3.0
vainfo: Supported profile and entrypoints
VAProfileMPEG2Simple : VAEntrypointVLD
VAProfileMPEG2Simple : VAEntrypointEncSlice
VAProfileMPEG2Main : VAEntrypointVLD
VAProfileMPEG2Main : VAEntrypointEncSlice
VAProfileH264ConstrainedBaseline: VAEntrypointVLD
VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
VAProfileH264ConstrainedBaseline: VAEntrypointEncSliceLP
VAProfileH264Main : VAEntrypointVLD
VAProfileH264Main : VAEntrypointEncSlice
VAProfileH264Main : VAEntrypointEncSliceLP
VAProfileH264High : VAEntrypointVLD
VAProfileH264High : VAEntrypointEncSlice
VAProfileH264High : VAEntrypointEncSliceLP
VAProfileH264MultiviewHigh : VAEntrypointVLD
VAProfileH264StereoHigh : VAEntrypointVLD
VAProfileVC1Simple : VAEntrypointVLD
VAProfileVC1Main : VAEntrypointVLD
VAProfileVC1Advanced : VAEntrypointVLD
VAProfileNone : VAEntrypointVideoProc
VAProfileJPEGBaseline : VAEntrypointVLD
VAProfileJPEGBaseline : VAEntrypointEncPicture
VAProfileVP8Version0_3 : VAEntrypointVLD
VAProfileHEVCMain : VAEntrypointVLD
VAProfileHEVCMain10 : VAEntrypointVLD
VAProfileVP9Profile0 : VAEntrypointVLD
VAProfileVP9Profile2 : VAEntrypointVLD
系统信息：
OS: Debian GNU/Linux 10 (buster)
CPU: Intel(R) Pentium(R) Gold G5400
Driver: intel-media-va-driver-non-free/testing,unstable,now 19.2.0+ds1-1
(tried testing,stable and free/non-free)
答案1
安装非免费驱动程序解决了我的问题：
apt install intel-media-va-driver-non-free i965-va-driver-shaders
答案2
我所做的就是使用
ffmpeg -hwaccel vaapi -i "infile" -vf scale=-2:size outfile.mp4 -vf scale=-2:1024,fps=fps=1/6 screenshots/%.jpg
我收到错误，因为我使用的是 nvidia 显卡，而它与 intel 显卡配合得很好。我猜是因为无法从驱动程序生成屏幕截图。所以我运行了两次或只是通过软件运行，因为我到底能获得多少编码/解码提升???
我想在英特尔 arc 视频系统上试用一下