Install nvidia accelerated ffmpeg in a conda environment.

ffmpeg_nvidia_conda_install.sh

git clone https://git.videolan.org/git/ffmpeg/nv-codec-headers.git
cd nv-codec-headers
vi Makefile   # change the first line to PREFIX = ${CONDA_PREFIX}
make install
cd ..

git clone https://git.ffmpeg.org/ffmpeg.git
cd ffmpeg
git checkout n4.2.2
conda install nasm
./configure --prefix=$CONDA_PREFIX --enable-cuda-sdk --enable-cuvid --enable-nvenc --enable-nonfree --enable-libnpp --extra-cflags=-I/usr/local/cuda/include --extra-ldflags=-L/usr/local/cuda/lib64
make -j 10
make install

###### DONE ######
### TIP:
# If CUDA is not installed, you can install without root permission as below.
bash cuda_10.2.89_440.33.01_linux.run --silent --override --toolkit --toolkitpath="$CUDA_DIR" --librarypath="$CUDA_LIB_DIR"

ffmpeg_nvidia_conda_install_advanced.sh

mkdir -p ~/ffmpeg_sources ~/bin

# NASM
cd ~/ffmpeg_sources && \
wget https://www.nasm.us/pub/nasm/releasebuilds/2.15.05/nasm-2.15.05.tar.bz2 && \
tar xjvf nasm-2.15.05.tar.bz2 && \
cd nasm-2.15.05 && \
./autogen.sh && \
PATH="$HOME/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" && \
make -j$(nproc) && \
make install

# libx264
cd ~/ffmpeg_sources && \
git -C x264 pull 2> /dev/null || git clone --depth 1 https://code.videolan.org/videolan/x264.git && \
cd x264 && \
PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" --enable-static --enable-pic && \
PATH="$HOME/bin:$PATH" make -j$(nproc) && \
make install

# cmake (for libx265, libaom, libsvtav1. if not installed already)
cd ~/bin && \
wget https://github.com/Kitware/CMake/releases/download/v3.21.2/cmake-3.21.2-linux-x86_64.tar.gz && \
tar xzf cmake-3.21.2-linux-x86_64.tar.gz --strip-components=1 -C "$HOME/ffmpeg_build" 

# libx265
cd ~/ffmpeg_sources && \
git -C x265_git pull 2> /dev/null || git clone https://bitbucket.org/multicoreware/x265_git && \
cd x265_git/build/linux && \
PATH="$HOME/bin:$PATH" cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/ffmpeg_build" -DENABLE_SHARED=off ../../source && \
PATH="$HOME/bin:$PATH" make -j$(nproc) && \
make install


# yasm (for libvpx. if not installed already)
cd ~/bin && \
wget http://www.tortall.net/projects/yasm/releases/yasm-1.3.0.tar.gz && \
tar xzf yasm-1.3.0.tar.gz && \
cd yasm-1.3.0 && \
./configure --prefix="$HOME/ffmpeg_build" && \
make -j$(nproc) && make install

# libvpx
cd ~/ffmpeg_sources && \
git -C libvpx pull 2> /dev/null || git clone --depth 1 https://chromium.googlesource.com/webm/libvpx.git && \
cd libvpx && \
PATH="$HOME/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" --disable-examples --disable-unit-tests --enable-vp9-highbitdepth --as=yasm && \
PATH="$HOME/bin:$HOME/ffmpeg_build/bin:$PATH" make -j$(nproc) && \
make install



# gnu m4 (for autoconf)
cd ~/bin && \
wget http://ftp.gnu.org/gnu/m4/m4-1.4.19.tar.gz && \
tar xzf m4-1.4.19.tar.gz && \
cd m4-1.4.19 && \
./configure --prefix="$HOME/ffmpeg_build" && \
make -j$(nproc) && \
make install


# autoconf (for libfdk-aac. if not installed already)
cd ~/bin && \ 
wget http://ftp.gnu.org/gnu/autoconf/autoconf-2.71.tar.gz && \
tar xzf autoconf-2.71.tar.gz
cd autoconf-2.71 && \
PATH="$HOME/ffmpeg_build/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" && \
make -j$(nproc) && \
make install

# automake
cd ~/bin && \
wget http://ftp.gnu.org/gnu/automake/automake-1.16.tar.gz && \
tar xfz automake-1.16.tar.gz && \
cd automake-1.16 && \
PATH="$HOME/ffmpeg_build/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" && \
make -j $(nproc) && make install

# libtool
cd ~/bin && \
wget http://ftp.jaist.ac.jp/pub/GNU/libtool/libtool-2.4.6.tar.gz && \
tar xvfz libtool-2.4.6.tar.gz && \
cd libtool-2.4.6 && \
PATH="$HOME/ffmpeg_build/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" && \
make -j $(nproc) && make install

# libfdk-aac
cd ~/ffmpeg_sources && \
git -C fdk-aac pull 2> /dev/null || git clone --depth 1 https://github.com/mstorsjo/fdk-aac && \
cd fdk-aac && \
PATH="$HOME/ffmpeg_build/bin:$PATH" autoreconf -fiv && \
./configure --prefix="$HOME/ffmpeg_build" --disable-shared && \
make -j$(nproc) && \
make install

# libmp3lame
cd ~/ffmpeg_sources && \
wget -O lame-3.100.tar.gz https://downloads.sourceforge.net/project/lame/lame/3.100/lame-3.100.tar.gz && \
tar xzvf lame-3.100.tar.gz && \
cd lame-3.100 && \
PATH="$HOME/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" --disable-shared --enable-nasm && \
PATH="$HOME/bin:$PATH" make -j$(nproc)&& \
make install

# libopus
cd ~/ffmpeg_sources && \
git -C opus pull 2> /dev/null || git clone --depth 1 https://github.com/xiph/opus.git && \
cd opus && \
PATH="$HOME/ffmpeg_build/bin:$PATH" ./autogen.sh && \
./configure --prefix="$HOME/ffmpeg_build" --disable-shared && \
make -j$(nproc) && \
make install

# libaom (av1 video)
cd ~/ffmpeg_sources && \
git -C aom pull 2> /dev/null || git clone --depth 1 https://aomedia.googlesource.com/aom && \
mkdir -p aom_build && \
cd aom_build && \
PATH="$HOME/bin:$PATH" cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/ffmpeg_build" -DENABLE_SHARED=off -DENABLE_NASM=on ../aom && \
PATH="$HOME/bin:$PATH" make -j$(nproc) && \
make install

# libsvtav1 (av1 video)
cd ~/ffmpeg_sources && \
git -C SVT-AV1 pull 2> /dev/null || git clone https://gitlab.com/AOMediaCodec/SVT-AV1.git && \
mkdir -p SVT-AV1/build && \
cd SVT-AV1/build && \
PATH="$HOME/bin:$PATH" cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/ffmpeg_build" -DCMAKE_BUILD_TYPE=Release -DBUILD_DEC=OFF -DBUILD_SHARED_LIBS=OFF .. && \
PATH="$HOME/bin:$PATH" make -j$(nproc) && \
make install

# libdav1d (av1 decode fast)
conda install meson
cd ~/ffmpeg_sources && \
git -C dav1d pull 2> /dev/null || git clone --depth 1 https://code.videolan.org/videolan/dav1d.git && \
mkdir -p dav1d/build && \
cd dav1d/build && \
meson setup -Denable_tools=false -Denable_tests=false --default-library=static .. --prefix "$HOME/ffmpeg_build" --libdir="$HOME/ffmpeg_build/lib" && \
ninja && \
ninja install

# libvmaf
cd ~/ffmpeg_sources && \
wget https://github.com/Netflix/vmaf/archive/v2.1.1.tar.gz && \
tar xvf v2.1.1.tar.gz && \
mkdir -p vmaf-2.1.1/libvmaf/build &&\
cd vmaf-2.1.1/libvmaf/build && \
meson setup -Denable_tests=false -Denable_docs=false --buildtype=release --default-library=static .. --prefix "$HOME/ffmpeg_build" --bindir="$HOME/bin" --libdir="$HOME/ffmpeg_build/lib" && \
ninja && \
ninja install

# gnutls
cd ~/bin && \
git clone https://gitlab.com/gnutls/gnutls.git && \
cd gnutls && \
git checkout 3.7.2 && \
./bootstrap && \
./configure --prefix="$HOME/ffmpeg_build" && \
make -j$(nproc) && make install

# nv-codec-headers
cd ~/bin && \
git clone https://git.videolan.org/git/ffmpeg/nv-codec-headers.git && \
cd nv-codec-headers && \
vi Makefile   # change the first line to PREFIX = ${CONDA_PREFIX}
make install

# ffmpeg
cd ~/ffmpeg_sources && \
wget -O ffmpeg-snapshot.tar.bz2 https://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2 && \
tar xjvf ffmpeg-snapshot.tar.bz2 && \
cd ffmpeg && \
PATH="$HOME/bin:$CUDA_DIR/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure \
  --prefix="$HOME/ffmpeg_build" \
  --extra-cflags="-I$HOME/ffmpeg_build/include" \
  --extra-ldflags="-L$HOME/ffmpeg_build/lib" \
  --extra-libs="-lpthread -lm" \
  --ld="g++" \
  --bindir="$HOME/bin" \
  --enable-gpl \
  --enable-gnutls \
  --enable-libaom \
  --enable-libfdk-aac \
  --enable-libfreetype \
  --enable-libmp3lame \
  --enable-libopus \
  --enable-libsvtav1 \
  --enable-libdav1d \
  --enable-libvpx \
  --enable-libx264 \
  --enable-nonfree \
  --enable-cuda-sdk \
  --enable-cuvid \
  --enable-nvenc \
  --enable-libnpp \
  --extra-cflags=-I"$CUDA_DIR/include" --extra-ldflags=-L"$CUDA_DIR/lib64" && \
PATH="$HOME/bin:$CUDA_DIR/bin:$PATH" make -j $(nproc) && \
make install && \
hash -r
#  --pkg-config-flags="--static" \
#  --enable-libass \
#  --enable-libvorbis \
#  --enable-libx265 \

NOTE that the A100 doesn't support NVENC: https://developer.nvidia.com/video-encode-and-decode-gpu-support-matrix-new