PXL-2000

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The PXL 2000 video camera

The Fisher-Price PXL2000 (also known as the PixelVision by Fisher-Price, and the KiddieCorder by some of its fans) is a toy black-and-white camcorder produced in 1987 that uses a compact audio cassette as its recording medium. The original designer at Fisher-Price was Andrew I. Bergman (February 14, 1950 - August 21, 2007) [1].

When the PXL2000 was available in retail outlets, it came in two versions—one with just the camera and necessary accessories (power supply, blank tape, etc.), and another which came packaged with a portable black and white television with a 4.5 in (114.3 mm) diagonal screen, for use as a monitor. There were also extra accessories sold separately, such as a carrying case.

Contents

[edit] Technical information

The PXL2000 consists of a simple aspherical lens, an infrared filter, a CCD image sensor, a custom ASIC (the Sanyo LA 7306M), and an audio cassette mechanism. This is mounted in a plastic housing with a bay for consumable batteries and a simple RF video modulator. A plastic viewfinder and some control buttons complete the device.

The fixed-focus, aspherical lens is of reasonable quality, and does not significantly differ from that found on many modern low-end digital cameras.[citation needed]

An ordinary cassette transport is used for storage of both audio and video. The PXL2000 holds 11 minutes of shooting by moving the tape at a high speed, roughly 16 7/8 in/s (429 mm/s) as opposed to cassette's standard speed of 1 7/8 in/s (48 mm/s) on a C90 CrO2 (chromium dioxide) cassette. The high speed is necessary because video requires a wider bandwidth than standard audio recording (In magnetic tape recording, the faster the recording speed, the more bandwidth can be recorded on the tape). The PXL2000 records the video information on the left audio channel of the cassette, and the audio on the right. [1]

In order to reduce the amount of information recorded to fit within the narrow bandwidth of the sped-up audio cassette, it uses an ASIC to generate slower video timings than conventional TVs use. It scanns the 90 by 120 pixel CCD fifteen times a second, feeding the results through a filtering network, and then to both a frequency modulation circuit driving the left channel of the cassette head and to an ADC, which fed the framestore.

The ASIC connects the digital output of the ADC to a block containing a digital framestore capable of storing two frames of video at the resolution of the image sensor. While one frame is read out of the CCD into the first framestore section, the previous frame is scanned out of the second framestore section at full TV frequency. The ASIC is also responsible for generating control signals for the CCD image sensor, and for generating automatic gain control (AGC) signals.

The PXL scans its 120 by 90 CCD fifteen times a second, meaning that it processes 162000 pixels per second (ignoring recovery time). The CCD clocks run at approximately 180 kHz. The tape runs nine times faster than an audio cassette, giving approximately 160 kHz of useful bandwidth. This meant that, assuming the tape behaves at specification, it can record only half of the information scanned out of the CCD. With this in mind, the PXL ASIC applies fairly heavy analogue filtering to the video signal to smooth it on exit from the CCD, then pre-emphasizes it, offsetting the disproportionate loss of higher frequencies.[citation needed]

For playback and view-through purposes, circuitry is included that takes image data from either the cassette or the CCD and uses it to fill the framestore at the PXL reduced rate, while scanning other half of the framestore at NTSC rates. Since each frame in the ping-pong framestore includes only 10800 pixels in its 120 by 90 array, the same as the CCD, the results were deemed to be marginal, and black borders were added around the picture, squashing the framestore image content into the middle of the frame, preserving pixels which would otherwise be lost in overscan. An anti-aliasing low-pass filter is included in the final video output circuit.

The PXL2000 has several weak points. The most common fault is a decayed drive belts - common to most tape mechanisms of the 1980s - and fogged blue filters. The blue filter is a glass optical component that is fitted behind the lens to prevent infrared light from reaching the CCD and producing miscoloured images. They tend to become fogged in stored PXLs, possibly as a result of outgassing from the plastic components of the camera. Many PXL2000s have also suffered damage from leaking electrolyte from old batteries, but this is usually not serious and can be easily repaired. Cameras left with tapes inserted for long periods of time may also need the tape path to be cleaned and a pinch wheel replacement.

[edit] Simulating the PXL2000

Simulating the PXL's simple hybrid design is quite difficult. Indeed, getting the cassette deck distortion just right has proven to be an extremely complex problem. One can, however, get close to the PXL's oddly ethereal quality by putting a video sequence through a number of different processing steps. These must be carried out in this order or the effect will be quite different.

  • Reduce the saturation to 0. The PXL2000 is a monochrome camera.
  • Reduce the frame rate to 15 frames per second. Deinterlace the video; the PXL does not interlace.
  • Reduce the resolution to 120 pixels by 90 pixels.
  • Apply a Gaussian blur function with a radius of about one and a half pixels. This mimics the lowpass filter.
  • Sharpen the image slightly (about 30%).
  • Clamp the black point to about 5% and the white point to about 95%.
  • Compress the dynamic range of the entire image by about 1.2 to 1.
  • Posterize to 90 steps
  • Add a lag effect; this should add a small proportion of the three previous frames to each frame, giving slight trails and motion artifacting
  • Add whichever video modulator simulation effect you prefer, plus some scanlines (since PXL is not interlaced)
  • Clamp the white and black points again
  • Apply a second Gaussian blur with the same radius
  • Add a black border around the image to push the edges of the image into the title safe area. (The image area is exactly 75% of a full 720 x 540 NTSC frame, or 540 x 405.)

The result of this process should resemble PXL2000 video. You can find the same information and an After Effects project file at: http://fox-gieg.com/tutorials/2008/fake-pxl2000-effect/

[edit] Revival in popularity

The PXL2000 has seen a revival in popularity since the early-to-mid 90s among independent graphic designers, experimental/avant-garde, and underground filmmakers, due to its unique low-resolution pixelated black & white image, with a lower frame rate of around 15 frame/s, akin to 8 mm or super 8 movie film (upconverted to the standard 30 frame/s in the camera). The image is also "windowboxed", meaning it has a black border around all sides of the picture.

PXL2000 cameras are still popular in the filmmaking scene—in fact, some individuals offer modifications for the PXL2000 to output composite video (the PXL2000 only has an RF output selectable to either North American television channel 3 or 4 in its unmodified stock condition), to interface to an external camcorder with a composite video in, or a VCR. The cameras themselves are still in demand, fetching prices as high as $200–500 on auction sites like eBay.

An image of a PXL2000 camera can be seen here: [2]

[edit] Package Descriptions

[edit] Model #3300 PXL2000 Camcorder

  • PXL2000 Camcorder
  • Mini bipod stand
  • Video switch box
  • Video Cable
  • One PXL2000 audio cassette tape
  • Instruction Booklet
  • 6 "AA" Duracell

The original retail price of this package was about $100. [3] [4]

[edit] Model #3305 PXL2000 Camcorder Deluxe System

  • PXL2000 Camcorder
  • Mini bipod stand
  • Video switch box
  • Video Cable
  • One PXL2000 audio cassette tape
  • Instruction Booklet
  • 4.5" diagonal black and white TV (with AC adapter)
  • 6 "AA" Duracell

The original retail price of this package was about $150. [5]

[edit] Famous uses

The PXL2000 was used by Richard Linklater in his 1991 debut film Slacker, during the bar scene.

Filmmaker Sadie Benning has also used the PXL2000 in some of her video works.

It was also used by Michael Almereyda for three of his films: the 1992 film Another Girl Another Planet, which was entirely shot with a PXL2000, his 1993 short Aliens, and his 1994 film Nadja, in which the PXL2000 was used for point of view shots of the title character. Ethan Hawke's character in Hamlet can also be seen with one.

See also: Category:Films shot in PixelVision

[edit] See also

[edit] References

  1. ^ US Patent 4875107

[edit] External links

Retrieved from "http://en.wikipedia.org/wiki/PXL-2000"
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