Production Notes

Cinematography

We filmed action for the Tehachapi DVD on the SP Mojave Subdivision between July of 1993 and August of 1994 with a Sony® CCD-FX710 Hi8® analog camcorder. This was a mid-level "prosumer" unit, which represented the then state of the art for a single Charged Coupled Device (CCD) image sensor camcorder.

Although Sony specified the Hi8 format had a higher signal-to-noise ratio then the JVC® S-VHS® format, we found that to be true only on paper. In actual practice the Hi8 format exhibits more visible noise in solid, dark areas. One can see this on backlit sides of freight cars, for example.

Digitization

We converted the Hi8 analog footage to digital video (DV) using the Pinnacle® Systems Studio® AV/DV hardware and software kit. Analog S-Video from a Sony EV-S7000 Hi8 playback deck with built-in time base correction was fed into the Pinnacle PCI card; analog audio into an SIS® on-board sound chip. Pinnacle Studio 8 software captured the audio and video streams to a DV quality Audio Video Interleave (AVI) file.

Scene Selection

We used four criteria in the following order for determining if a shot made the cut for the final production:

• Action: preference given to meets over a simple run-by.
• Uniqueness: probability of seeing a similar consist.
• Geography: portion of the line represented.
• Quality: cinematography and lighting evaluated.

Note quality, although important, was last on our criteria. Consequently there is some footage of fairly low technical quality that made the final cut.

After editing the first draft, we had about eleven minutes of DVD space left. We added another six minutes of bonus footage for scenes of merit that did not make the final cut.

Editing

We wanted to produce a feature that appeals to a broader base then just die-hard railfans. We were rather liberal in deleting footage during editing. On average scenes are about half the length of time it took the train to pass the camera.

We deliberately removed content when we felt a scene was dragging. Consequently we use more cuts and dissolves then the average railfan video. If a specific cut seems a bit too long, look for other details such as people in the scene!

We took advantage of digital editing to remove individual frames with excess noise or distortion. In several cases one to three frames were simply deleted because there was a distorted image, repeated scan line, or other dropout artifact. The longest such cut is seven frames, or almost a quarter second!

Video and Audio

We did not make any correction to video image color or exposure. Instead we see the result of four automatic signal processors each making independent correction decisions: one in the camera, one in the playback deck, one in the DVD player, and one in the television itself. When viewed on a television set manufactured in the past ten years or so, color and saturation should be very good without adjustment.

We did play more with the audio, however. We maintained a continuous audio track even if the video changed. For example when a shot pans from east to west, we drop about three to five seconds of real time. We cut the video while the camera moves. But we lock the sound on either the opening or closing scene so the sound remains contiguous. Watch the sample video of ATSF 8158 WB going past Tehachapi Station for an example of such an edit.

Final Production

We used Studio 8 to edit the entire production. But with a total of about five hundred scenes and eight hundred edit points, we could not roll this into one project: Studio 8 became unusable once the project grew over four hundred scenes. It has difficulty with projects having about fifteen DVD menu pages as well.

We finally built the DVD from smaller Studio 8 projects for which the output was an intermediate AVI file. We used the highest quality possible at this stage resulting in some but negligible resolution loss. The intermediate AVIs were edited together to build the final production. Rendering the DVD takes four hours and fifteen minutes on an Athlon® XP 2000+ system with 768 megabytes of memory.

These advertisements are provided by Google and its partners.