You can use red official program "REDline"
Download It from here https://www.red.com/download/redline-linux-beta
It's a shell script. to install it. From properties change it's permission to allow execute.
Now open it in terminal and install it
$ sudo <filelocation/file.sh>
if you are in a installer directory you can install it by running
$ sudo ./file.sh
Now after installing it.
Currently it's a command line program.
normally you can convert R3D (red video files to other formats like openexr,tiff , jpeg ) files to image sequences and also you extract audio too.
Now if i want to convert a R3D files to jpeg sequences the command would be like this
$ REDline -i <filelocation/file.R3D> --format 3 -o filename
let me explain what are these commands and options are
here REDline is our program for converting R3D files to image sequences
-i means video for converting
--format 3 means convert to what format currently the program supports DPX , Tiff, OpenEXR , JPEG, SGI, R3D Trim, Apple ProRes and Avid DNX formats. now what does 3 means 3 means convert R3D files to image sequences. so how can you convert to Tiff format use number 1. for other formats you can use
DPX = 0, OpenEXR = 2, SGI = 4, R3D Trim = 102, Apple ProRes=201, Avid DNX = 204
-o means output file name because you are converting to jpeg image sequences the program will automatically name it.like wise