PATH="$HOME/bin:$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" \
>   --bindir="$HOME/bin" \
>   --enable-gpl \
>   --enable-libass \
>   --enable-libfdk-aac \
>   --enable-libfreetype \
>   --enable-libmp3lame \
>   --enable-libopus \
>   --enable-libtheora \
>   --enable-libvorbis \
>   --enable-libvpx \
>   --enable-libx264 \
>   --enable-nonfree
bash: ./configure: No such file or directory