Telecine

Got lots of 8mm film but no projector? Would you like to see those 30-year-old home movies your parents made when you were a kid one more time? Here's how a Linux system can be used to convert 8mm film to DVD movies.
Media Conversions, my business, converts videotape and slides to DVD. My customers often ask if I also can convert 8mm film. This is the story of my adventure into converting filmto DVD. There are a number of ways to make a conversion. You can run the film through a projector and use a video camera to capture the images. Although, finding a working projector is difficult. Belts and rubber drive components dry up. Worse, 30-year-old rolls of film, some with splices, may no longer stand up to the stress of being projected at 18 frames/second (f/s). Plus, most video camerasrun at 30f/s and will not synchronize with the projector.
Telecines have been used since the early days of broadcast TV to convert film to video. A number of Web sites describe DIY Telecine projects (see Resources). Generally, they either rebuild a projector and use a still camera, or they utilize a flatbed scanner and a custom film transport. Based on my research, I decided to build a Telecineusing a flatbed scanner. The cost of entry is low, and scanners running at 3,000dpi or above are a commodity item. You can get started on the conversion software without the film transport, and you don't need custom optics. The downside, if you're not a programmer, is that you have to write all of your own software.
I decided early in the project that I wanted to use only open-source software tools.I hosted it on an Ubuntu Linux desktop system. I knew I would need a programming language with support for scanning, serial (or parallel) port communication, a math library and an image library. A plotting and drawing library also would be helpful during program development. I also wanted a language that offered ease of programming in higher-level constructs. I was familiar with C, but did notwant to use it for this project, so instead, I decided to use Python. Python is easy to learn, it's well supported by the Linux community in both on-line forums and with numerous examples of code, and error handling and type checking/conversion are part of the language. Plus, the Python Imaging Library includes an interface to SANE for scanner support.
I acquired an Epson Perfection 3490 photoscanner for the project. It has SANE drivers, a built-in backlight for film scanning and offers 3,200dpi resolution.
There are four steps to converting a roll of film: scan the film in segments, find the image frames in the segments, remove duplicate frames where the segments overlap and make a movie from the frames. I wrote three separate Python programs for the first three steps and used FFmpeg forthe fourth. The software relies on cheap disk space. Frame files are copied from segment scans. Overlap removal makes a second, renumbered, copy of all of the frame files. This strategy allows each of those programs to be rerun with the same segment scans for debugging and program development.
The cost, for a 50-foot roll of film, is approximately 8GB of space for the segment scans and similaramounts of space for the log file (if debug is turned on) and each of the frame file sets. Files are written into subdirectories of the current directory and numbered sequentially. A root filename, given as a command-line argument, is used as a prefix. Scan data is written into the scans directory, and frame files are written to the frames directory. If logging is turned on, log files are writtento the logs. If debug is left on (default setting), marked up copies of the scan files also are written to the logs. The markings show where the edges of the sprocket holes were found and the outline of the frame extracted. Finally, overlap-removed, renumbered frames are written to the movie directory.
The program for scanning film simply calls the SANE scanner interface, saves the scan data,...