Options for Stereoscopic Preview

Viewing stereoscopic media in realtime requires that the combined stream be transmitted to your display in some form.  Originally this was accomplished with two independent streams going to two separate output devices, like polarized projectors, or LCD monitors with a beam splitting mirror box.  Now with standalone 3D displays, usually the source streams have to be processed in some way to combine them.  Panasonic’s professional 3D display accepts separate left and right SDI streams, but most other monitors require the sources to be combined in some way, either spatially or temporally.  Passively polarized LCDs usually require a single stream with the left and right views interlaced together, which reduces the viewable resolution, but can be transmitted over regular SDI, DVI or HDMI connections.  120hz displays require left and right frames interleaved together, usually over HDMI 1.4.  Standard 2D displays require anaglyphic processing to combine the images, and color filtered glasses for the viewer to get a monochromatic preview of the depth illusion.

Luckily there are a number of standalone products that can combine separate left and right source streams into a single usable muxed stereoscopic video stream.  Blackmagic’s HDLink 3D is one of the more affordable options, and is compatible with most display output options.  The development of these new converters allows many more flexible options for connecting 3D devices together.  Most realtime 3D monitoring of stereoscopic shooting will require a solution that can accept dual SDI streams, but with a simple conversion box, those sources can be run directly into an inexpensive consumer 3D display, with no other hardware required.

In the edit bay, stereoscopic content can be output from a workstation in a number of forms.  AJA and NVidia can output separate SDI streams for each eye, using the same display interface that would be used onset.  Combining the left and right view into a single stream allows it to be played out a single SDI port or even standard DVI on a GPU to a passive 3D display.  Those specific options will depend on what software you are using, and need to match your display requirements.  Outputting 120hz from a dedicated HDMI 1.4 port requires a newer GPU and specific application support, but greatly simplifies the hardware setup.  I am sure there will be a whole variety of new options announced at NAB next month, and as new hardware and software tools are developed, the preview options become cheaper to setup and easier to use.

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