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JPEG Compression/Decompression
StudioZ SDI can capture and play back full-rate, full-frame video while performing
hardware-accelerated motion JPEG compression and decompression. As video frames are
digitized, they may be JPEG compressed, written to system memory, and then written to hard
disk. This compression reduces the disk data rate required for full-rate, full-frame capture.
The actual disk data rate is a function of the Video Quality value set during StudioZ driver
configuration, the image content of the video captured, and the amount of hard disk space
that is used.
NOTE
See “Configuring the StudioZ Driver” in Chapter 1 for informat ion about setting the Value
Quality.
Motion JPEG encoding is an intraframe compression scheme. Each field is compressed
individually, allowing frame boundary editing at any point in the video. The reconstructed
JPEG image is not a bit-for-bit copy of the original image. You can adjust the image quality
by changing the Video Quality value during StudioZ driver configuration.
NOTE
You can also adjust the Video Quality value in StudioZ Central Plus. See the
StudioZ Central
Plus Quick-Start Guide for more information.
You can compress images (raster data blocks) in system memory and then store them in
system memory. You can also decompress compressed images, with system memory serving
as both the source and destination. With the exception of 720 x 486, images must be
composed of an integer multiple of 16 x 16 pixel blocks.
StudioZ provides DMA capability to allow compression and decompression to occur with
minimal host processor intervention.
Video I/O
StudioZ accepts SDI input in either 525 line/59.94 Hz (NTSC) or 625 line/50 Hz (PAL)
format. The 10-bit-per-component input is processed by input lookup tables for 10-bit-per-
component to 8-bit-per-component transformation, and for brightness, contrast, hue, and
saturation adjustment.
The StudioZ video encoder takes digital YUV 4:2:2 data and produces SDI, S-video, and
composite outputs in either 525/59.94 Hz or 625/50 Hz formats. Lookup tables convert 8-
bit-per-component output data to 10-bit-per-component output data and can provide
brightness, contrast, hue, and saturation adjustment.
