ViewCast Osprey PCI, User Manual

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AVStream Driver Reference Information
76 ViewCast
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With SimulStream enabled, there can be multiple capture pins and multiple preview pins. Each
capture and preview pin pair is placed on a separate filter. The maximum number of each type of
pin is the same as the maximum number of filters you have elected to expose in the SimulStream
control group. Any pin can produce video at any size, rate, color format, and crop setting. Of
course, there will be practical limits imposed by the bandwidth of the machine.
The following post processing filters can be applied, with or without SimulStream enabled:
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Motion adaptive deinterlacing and inverse telecine
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Gamma correction
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Logos
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On-video caption rendering
Some of these filters operate globally on all filters and pins of a device, and some operate on a per-
filter or per-pin basis:
The Video Proc Amp controls – Brightness, contrast, hue, saturation, and sharpness – are applied
globally in hardware to the incoming video.
The basic reference size – CCIR-601 or square pixel – is established in hardware. Horizontal delay
and Osprey 530/540/560 720/704 width select are also performed in hardware.
Deinterlace / inverse telecine and gamma correction are applied to all filters and pins on the device
and have the same settings for all filters and pins. (Adaptive deinterlacing does not affect quality of
single field 2:1 or 4:1 exact-scaled video, so long as the sharp algorithm is used. Inverse telecine
does not affect single field exact-scaled video.)
Crop, logo, and caption settings can be different for each pin of each filter, and the driver maintains
separate settings for each filter and pin.
Video size, color format, and frame rate can also be different for each pin. It is the responsibility of
the application to maintain these settings.
Efficient Video Rendering
The following information is primarily useful to developers, but may also be helpful for those who
want to fine-tune existing applications. If you are seeing poor rendering performance, in terms of
either excessive CPU utilization or jerky, stuttering video, read this section.
There are at least four basic ways to render video from the capture driver onto the screen. They vary
greatly in their efficiency, and applications do not always make the best choice of renderer.
In these descriptions, it is assumed that the AVStream driver’s Preview Pin is being used. The results
would be the same if the Capture Pin were used instead.