The OCTANE Personal Video option supports 1280 x 1024 at 50 Hz, 60 Hz, and 72 Hz. Input speed is limited by the pixel clock and input to the video output controller (VOC). The VOC receives the complete graphics stream as input; it can select all or a portion of the screen to resize and fit into a standard video raster.

The section “OCTANE Personal Video Software Model” explains how the board looks to the software.

Figure 1-1 diagrams the OCTANE Personal Video board.

Figure 1-2 shows OCTANE Personal Video option connections to OCTANE graphics and connectors.

All graphics data comes through three dedicated internal flex cables connected to OCTANE graphics. Through connectors on the OCTANE Personal Video board itself, you can

Figure 1-3 shows the connectors.

Table 1-1 summarizes board connectors.

The board can genlock to external reference, O2 video, or Internal Video Sync. The sources for external reference are reference, composite video, and S-VHS video. The lock is color-frame accurate with respect to reference or composite video. Other important signals (reset, power rails, and so on) come from the board connection at the XIO slot.

For hardware details, including cabling information, see the OCTANE Personal Video Installation Guide.

The OCTANE Personal Video board can capture video from four sources:

Video input processing captures input from one or more of these sources and transfers it to memory. During capture, you can scale (reduce, or minify) the image horizontally and vertically, such as for aspect ratio correction. The scaler is a YUV device only.

You can also color-space convert the image (CSC). The color-space converters allow transformation from YUV to RGB or from RGB to YUV.

Finally, you can DMA the image into memory; the board supports two DMA channels. Figure 1-4 diagrams the processing path.

Video output takes an image from memory and converts it into video, or performs the print-to-video process. Output video sources are memory, graphics (VOC), or video in (analog or digital). From memory, the board can process 8-bit YUV 422 or 24-bit RGB. (Although you can transfer 10- bit YUV, the processing path is only 8 bits wide.) If required, you can color-space convert the signal into the YUV 422 format.

After color-space conversion, the signal can go into a sampling rate converter, which scales a square-pixel image into a nonsquare-pixel image. The encoder is a nonsquare encoder; it expects 720 pixels per line. This conversion might be necessary because the video encoder operates on nonsquare pixels only; it does not directly accept square-pixel data. This filter is explained further in “Square-to-Nonsquare Pixel Filter,” later in this section.

Figure 1-5 diagrams the processing path of the output block.

The scaler scales down horizontally and vertically only (no upscaling).

Figure 1-6 diagrams the processing path using graphics as the video source.

The OCTANE Personal Video option supports

Most applications native to the computing environment work in the square-pixel aspect ratio. However, professional video applications require nonsquare pixels, which preserve the correct aspect ratio.

The OCTANE Personal Video board can process video in square-pixel format. For optimum video quality, however, it outputs only nonsquare pixels. To accommodate both environments, the board includes a bypassable square-to-nonsquare pixel filter that operates on video.

Square-pixel NTSC has 640 active pixels per line, based on a sample clock of 12.2727 MHz. Square pixel PAL has 768 pixels per line, based on a sample clock of 14.75 MHz. Nonsquare pixel NTSC and PAL both have 720 pixels per line, based on a sample clock of 13.5 MHz. Thus, in the horizontal direction, the filter must decimate in PAL and interpolate in NTSC. (For simplification, the vertical scale is not considered.)

The OCTANE Personal Video board utilizes timing signals from three kinds of sources:

The board can produce the Internal Video Sync signal.

The video daemon /usr/etc/videod, which has device-dependent and device-independent portions, handles video device management and status information.

The generic video tools include

The vlinfo, vidtomem, and memtovid tools are command-line tools. In addition to their reference pages, these tools have explanations in the Media Control Panels User's Guide. Similar applications are supplied in source-code form as examples in the directories /usr/share/src/dmedia/video/vl and /usr/share/src/dmedia/video/vl/OpenGL.

The client library is /usr/lib/libvl.so. The header files for the VL are in /usr/include/dmedia. The header file for the VL, vl.h, contains the main definition of the VL API and controls. The header file for OCTANE Personal Video is /usr/include/dmedia/vl_evo.h (linked to /usr/include/vl/dev_evo.h).

The node is an endpoint or internal processing element of the path, such as a video source like a VTR, video drain (such as to memory or a video output), or a device (video).

The path is an abstraction for a way of moving data around. A path is a set of nodes with video routes (connections) between the ports on the nodes. A path defines the useful connections between video sources and video drains. Figure 1-8 shows a simple path in which a frame from a videotape is captured to memory.

Figure 1-9 shows a more complex path with two video drains: a frame from a workstation window is captured to memory and sent to video output simultaneously. This path is set up in stages.

Figure 1-10 diagrams how the OCTANE Personal Video board looks to software.

Memory nodes appear as both source and drains. These nodes cannot be both at the same time; source and drain modes are mutually exclusive.

The board's crossbar switch allows any source to connect to any drain. Multiple connections can be made simultaneously. For example, the board can capture video and transfer it to memory simultaneously; it can capture video and transfer it to one memory drain in YUV format and the other in RGB format, all simultaneously.