multimedia/ffmpeg: configure with --enable-cuda-llvm when NVENC is set

Preamble: I made this change a while ago but couldn't find time to share it.
Now I see that ffmpeg 8 is in the works, so maybe I am too late or, at least, 
the change will need some rework.

I haven't spelled it out in the commit message but the change allows doing 
things like:
$ nv-sglrun ffmpeg -y -hwaccel cuda -hwaccel_output_format cuda -i input.avi 
-fps_mode passthrough -c:a copy -c:v h264_nvenc -filter:v "scale_cuda=720:-1" 
-b:v 5M output.mp4

(With supported NVIDIA hardware, of course).

commit 0c20fc738c548d97faead8ffb0d8b74ff01b4cb3
Author:     Andriy Gapon <avg@FreeBSD.org>
AuthorDate: Sat Jun 21 18:02:02 2025 +0300
Commit:     Andriy Gapon <avg@FreeBSD.org>
CommitDate: Sat Sep 6 15:47:50 2025 +0300

     multimedia/ffmpeg: configure with --enable-cuda-llvm when NVENC is set

     Thanks to that option, various CUDA filters, such as scale_cuda,
     for instance, would be enabled in addition to NVIDIA / CUDA encoders and
     decoders.

     Maybe this should be under a new port option because it requires clang
     from llvm port for nvptx64-nvidia-cuda target support.
     However llvm is required only during build time, there are no extra
     dependencies for the ffmpeg package.

diff --git a/multimedia/ffmpeg/Makefile b/multimedia/ffmpeg/Makefile
index fd25b9238021..afa013b7699b 100644
--- a/multimedia/ffmpeg/Makefile
+++ b/multimedia/ffmpeg/Makefile
@@ -387,6 +387,7 @@ NETWORK_CONFIGURE_ENABLE=	network
  # nvenc
  NVENC_BUILD_DEPENDS=	ffnvcodec-headers>=11.1.5.2:multimedia/ffnvcodec-headers
  NVENC_CONFIGURE_ENABLE=	nvenc
+NVENC_CONFIGURE_ON=	--enable-cuda-llvm --nvcc=${LLVM_PREFIX}/bin/clang

  # OpenAL
  OPENAL_LIB_DEPENDS=	libopenal.so:audio/openal-soft
@@ -680,6 +681,10 @@ LICENSE_TEXT_NONFREE=	enabling OPENSSL or FDK_AAC restricts 
redistribution
  LICENSE_PERMS_NONFREE=	auto-accept
  .endif

+.if ${PORT_OPTIONS:MNVENC}
+USES+=		llvm:build,noexport
+.endif
+
  post-install:
  	(cd ${WRKSRC} && ${COPYTREE_SHARE} \
  		"${DOC_FILES}" ${STAGEDIR}${DOCSDIR})


P.S.

Full output from an ffmpeg command like the above:

$ nv-sglrun ffmpeg -y -hwaccel cuda -hwaccel_output_format cuda -i input.avi 
-fps_mode passthrough -c:a copy -c:v h264_nvenc -filter:v "scale_cuda=720:-1" 
-b:v 5M output.mp4
/usr/local/lib/libc6-shim/libc6.so: shim init
ffmpeg version 6.1.2 Copyright (c) 2000-2024 the FFmpeg developers
   built with FreeBSD clang version 19.1.7 
(https://github.com/llvm/llvm-project.git llvmorg-19.1.7-0-gcd708029e0b2)
   configuration: --prefix=/usr/local --mandir=/usr/local/share/man 
--datadir=/usr/local/share/ffmpeg --docdir=/usr/local/share/doc/ffmpeg 
--pkgconfigdir=/usr/local/libdata/pkgconfig --disable-static --disable-libcelt 
--enable-shared --enable-pic --enable-gpl --cc=cc --cxx=c++ --disable-alsa 
--disable-libopencore-amrnb --disable-libopencore-amrwb --enable-libaom 
--disable-libaribb24 --disable-libaribcaption --enable-asm --enable-libass 
--disable-libbs2b --disable-libcaca --disable-libcdio --disable-libcodec2 
--enable-libdav1d --disable-libdavs2 --disable-libdc1394 --disable-debug 
--enable-htmlpages --enable-libdrm --disable-libfdk-aac --disable-libflite 
--enable-fontconfig --enable-libfreetype --enable-frei0r --disable-libfribidi 
--disable-gcrypt --disable-libglslang --disable-libgme --enable-gmp 
--enable-gnutls --enable-version3 --disable-libgsm --enable-libharfbuzz 
--enable-iconv --disable-libilbc --disable-libjack --enable-libjxl 
--disable-libklvanc --disable-libkvazaar --disable-ladspa --enable-libmp3lame 
--enable-lcms2 --disable-liblensfun --disable-libbluray --enable-libplacebo 
--disable-librsvg --enable-libxml2 --enable-lto --disable-lv2 --disable-mbedtls 
--disable-libmfx --disable-libmodplug --disable-libmysofa --enable-network 
--disable-nonfree --enable-nvenc --enable-cuda-llvm 
--nvcc=/usr/local/llvm19/bin/clang --disable-openal --disable-opencl 
--disable-opengl --disable-libopenh264 --disable-libopenjpeg 
--disable-libopenmpt --disable-openssl --disable-libopenvino 
--enable-optimizations --enable-libopus --disable-pocketsphinx --enable-libpulse 
--disable-librabbitmq --disable-librav1e --disable-librist 
--enable-runtime-cpudetect --disable-librubberband --disable-sdl2 
--enable-libshaderc --disable-libsmbclient --disable-libsnappy --disable-sndio 
--disable-libsoxr --disable-libspeex --disable-libsrt --disable-libssh 
--enable-libsvtav1 --disable-libtensorflow --disable-libtesseract 
--disable-libtheora --disable-libtwolame --disable-libuavs3d --enable-libv4l2 
--enable-vaapi --disable-vapoursynth --enable-vdpau --disable-libvidstab 
--enable-libvmaf --enable-libvorbis --disable-libvo-amrwbenc --disable-libvpl 
--enable-libvpx --enable-vulkan --enable-libwebp --enable-libx264 
--enable-libx265 --disable-libxavs2 --enable-libxcb --disable-libxvid 
--disable-outdev=xv --disable-libzimg --disable-libzmq --disable-libzvbi
   libavutil      58. 29.100 / 58. 29.100
   libavcodec     60. 31.102 / 60. 31.102
   libavformat    60. 16.100 / 60. 16.100
   libavdevice    60.  3.100 / 60.  3.100
   libavfilter     9. 12.100 /  9. 12.100
   libswscale      7.  5.100 /  7.  5.100
   libswresample   4. 12.100 /  4. 12.100
   libpostproc    57.  3.100 / 57.  3.100
Input #0, avi, from 'input.avi':
   Metadata:
     software        : Lavf55.12.100
   Duration: 00:09:02.72, start: 0.000000, bitrate: 27780 kb/s
   Stream #0:0: Video: mjpeg (Baseline) (MJPG / 0x47504A4D), yuvj422p(pc, 
bt470bg/unknown/unknown), 1920x1072, 27777 kb/s, 25 fps, 25 tbr, 25 tbn
Stream mapping:
   Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (h264_nvenc))
Press [q] to stop, [?] for help
Output #0, mp4, to 'output.mp4':
   Metadata:
     software        : Lavf55.12.100
     encoder         : Lavf60.16.100
   Stream #0:0: Video: h264 (Main) (avc1 / 0x31637661), cuda(pc, 
bt470bg/unknown/unknown, progressive), 720x402, q=2-31, 5000 kb/s, 25 fps, 12800 tbn
     Metadata:
       encoder         : Lavc60.31.102 h264_nvenc
     Side data:
       cpb: bitrate max/min/avg: 0/0/5000000 buffer size: 10000000 vbv_delay: N/A
[out#0/mp4 @ 0xf1d39c51340] video:331700kB audio:0kB subtitle:0kB other 
streams:0kB global headers:0kB muxing overhead: 0.049572%
frame=13568 fps=222 q=23.0 Lsize=  331864kB time=00:09:02.56 
bitrate=5010.7kbits/s speed= 8.9x


-- 
Andriy Gapon