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Osprey 240e/450e User Guide
ViewCast 75
Video standards and sizes
Video standard refers to whether the video signal format is NTSC, PAL, or SECAM. Depending on the
exact product version you have, some or all of the following standards are available:
525-line formats:
NTSC-M – North America
NTSC-J – Japan
625-line formats:
PAL-B, D, G, H, I – many countries in Europe and elsewhere. B, D, G, H, and I refer to five
nearly identical subformats
Full-sized NTSC-M and NTSC-J have 525 lines total, 480 lines visible, per frame and a display rate of 59.94
fields per second, or 29.97 interlaced frames per second. Although capture-to-PC applications normally
use only 480 video lines, the full NTSC frame actually contains 485 video lines, and the AVStream driver
provides a control to capture all 485 lines. The control is located on the RefSize property tab.
Full-sized PAL and SECAM have 625 lines total, 576 lines visible, per frame and a display rate of 50 fields
per second, or 25 interlaced frames per second.
The standard frame sizes are different for NTSC and PAL. For example, the half-frame size in pixels is 360
x 240 for NTSC, and 360 x 288 for PAL. The driver automatically adjusts the reference size and default
size for the video standard you are using.
Color formats
The Color format is the arrangement of data bits representing the colors of each pixel. For example, in
the RGB555 format, each pixel of data is stored as 5 bits of red, 5 bits of green, and 5 bits of blue color
information.
Video delivered by the Osprey board to the system is in uncompressed format. It is possible to compress
the video at a subsequent stage of processing. However, this dialog field refers specifically to the
uncompressed raw video that the board delivers to the system.
The Osprey AVStream driver supports the following capture pin formats.
YUY2 and UYVY – Each pixel is represented with a total of 2 bytes (16 bits) of data. The data
is encoded as separate data for luminance (intensity) and chrominance (color). This mode is
mainly used as an input to software compressors. See YUV format details.
YUV12 planar – Also known as I420. This format is complex – there are aggregate 12 bits of
data per pixel. Each pixel has 8 bits of luminance data. Each group of 4 adjacent pixels
arranged in a 2 x 2 square shares two bytes of chrominance data. See YUV format details.
YVU9 planar – Similar to YUV12 planar, except there are aggregate 9 bits of data per pixel,
and each byte pair of chrominance data is shared by 16 adjacent pixels arranged in a 4x4
square. See YUV format details.
RGB32 – Each pixel has four bytes (32 bits) of data – one each for red, green, and blue, plus
one byte that is unused. The pixel has 256 shades of each of the three colors, for a total of
16.7 million colors.