The OCTANE Compression motion JPEG option card from Silicon Graphics provides two independent channels for compression and decompression for the OCTANE desktop workstation. Besides compressing and decompressing still images, OCTANE Compression enables an OCTANE workstation to input and output compressed video and record it to disk or videotape. When OCTANE Digital Video is also installed in the workstation, you can input and output CCIR 601 digital video.
In this chapter:
“OCTANE Compression Features” presents specific features of the hardware.
“OCTANE Compression and Video Options” summarizes how the compression board and the OCTANE Digital Video option interact.
“OCTANE Compression and the Compression Library” introduces the CL.
“OCTANE Compression and the Video Library” introduces the VL.
Designed to work with the OCTANE Digital Video option, OCTANE Compression overcomes the obstacle presented by the colossal data streams that video sources generate. Thus, OCTANE Compression is a powerful tool for video production, digital video distribution, motion video analysis, and video-based training. OCTANE Compression is an integral part of the digital studio that combines leading computer graphics, image processing, digital video, and high-quality video in an efficient desktop environment.
For applications that demand broadcast quality, OCTANE Compression with OCTANE Digital Video allows compressed digital video streams to be used as elements in sophisticated effects such as real-time keying, blending, and video texture mapping. The option provides an ideal environment for broadcast-quality nonlinear editing, spot playback, and still storage.
OCTANE Compression is an integral part of the Silicon Studio solution for film and video production, which integrates 2D and 3D graphics, image processing, digital audio, and high-quality video in a single environment.
OCTANE Compression features include
the ability to encode or decode the board's two channels in any combination
capture and playback of full-resolution, full-motion video to and from memory or disk in real time:
60 fields, or 30 frames, per second compression and decompression of full-resolution NTSC video
50 fields, or 25 frames, per second compression and decompression of full-resolution PAL video
single-frame compression and decompression
composite or S-Video capture, and playback with genlock capability
compression ratios as low as 2:1
during real-time compression, scaling of full-size fields by half in the horizontal or vertical direction or both
real-time color-space conversion in memory-to-memory decompression or uncompressed video capture or playback modes
during decompressing to main memory or uncompressed video capture, image scaling for flexible viewing of video clips and for processing transitions and effects
compatibility with all OCTANE graphics solutions
data formats: 8-bit per component 4:2:2 YUV, XBGR, or RGBX (32 bits per pixel, 8 bits per component)
capture of uncompressed data to memory; playback of uncompressed data from memory
OCTANE Compression has these modes of operation:
capturing uncompressed video from the base analog input or optional OCTANE Digital Video option into a memory buffer
playing back of uncompressed video from a memory buffer to the base analog output or optional OCTANE Digital Video option
compressing video from the base analog input or optional OCTANE Digital Video option into a memory buffer
decompressing video from a buffer to the base analog output or optional OCTANE Digital Video option
compressing an image stored in memory into another area of memory
decompressing a stored compressed image and placing it into another area of memory
Because of the high data rates produced by video sources, your priorities might alternate between image quality on the one hand and storage size and transmission bandwidth on the other. OCTANE Compression adjusts to your needs with a wide range of compression ratios under complete software control.
OCTANE Compression works with the Compression Library, a complete API for compressing single images, video-streaming applications, and more.
The OCTANE Compression option can be used as a simple analog capture and playback device for video, or with the OCTANE Digital Video option for capture and playback and for CCIR 601 digital video.
The OCTANE Compression option's real-time compression and decompression lets you perform nonlinear editing and real-time playback from disk of special effects, composites, and animations. The OCTANE Compression option uses JPEG, the ideal compression algorithm for postproduction processes because it preserves individual video frames.
The Silicon Graphics Compression Library (CL) was designed to exploit the full capabilities of the OCTANE Compression option:
compression ratios
data formats
in conjunction with the Video Library, capture and playback to and from video destinations
digital movie recording, editing, and playback
The CL provides three interfaces, for successively more complex compression: a still image API for single images, a sequential access API for video-streaming applications, and a buffered interface. Chapter 2, “Programming With the Compression Library,” explains these interfaces in detail.
The CL works with other Silicon Graphics Digital Media libraries—Audio Library (AL) and Movie Library (ML)—as well as the Video Library (VL).
 | Note: Although the CL supports audio compression, the OCTANE Compression board does not. |
The Video Library provides a software interface to the OCTANE Compression board, which lets applications
capture live video in system memory
encode graphics to video in real time
produce full-rate video output
The Video Library (VL) is a collection of device-independent and device-dependent C language calls for Silicon Graphics workstations equipped with video options. The VL provides generic video tools, including simple tools for importing and exporting digital data to and from Silicon Graphics systems or third-party video devices that adhere to the Silicon Graphics architectural model for video devices.
Chapter 3, “Programming With the Video Library,” explains the basics of using the VL to create video programs for OCTANE Compression.