The Combiner has a dedicated channel for use when the Sirius Video option is installed. This chapter explains how to use the Combiner's Sirius Video channel:
setting up the Sirius Video channel
modifying Sirius Video channel attributes
When the Sirius Video option is installed, the button labeled Sirius on the Combiner main window is accessible.
Like the Encoder channel, the Sirius Video channel can be set up in independent mode or dependent mode. Use the Sirius Video Attributes window.
 | Note: For the combination to be valid, the swap rates of all channels, including the Sirius Video channel, must match. For more information on the swap rate, see “Swap Rate” in Chapter 5. |
In the Sirius Attributes window, select None in the Source Channel popup menu to set up the Sirius Video channel in independent mode. In this mode, pixels coming to the Sirius Video channel are 10 bits.
Like other channels, the Sirius Video channel in independent mode consumes pixel bandwidth. The Combiner validates the selection along with the other channels.
For dependent mode, select a specific channel in the Source Channel popup menu on which the Sirius Video channel is to be dependent. In this mode, a portion of the visible surface from one of the other high-resolution channels (as selected in the Source Channel popup menu) is sent to the Sirius Video channel for video out. Like the Encoder channel, the Sirius Video channel can roam within its source channel.
If the size of the selected region matches the size of the output format, the Sirius Video option uses a precision of 10 bits per component and does not process the pixels (pass-through mode). However, if you have enlarged the input size so that it is larger than the output size of the format, pixels are filtered and processed to fit the output size (reduced mode). Filtered pixels have a precision of 8 bits per component.
| Note: On systems with the Sirius Video option, set up the default video combination with the Sirius Video channel dependent on a high-resolution channel. If you want the alpha component, select the RGBA10 pixel format on both the Sirius Video channel and the channel on which it is dependent. |
Double-click the Sirius button in the Combiner main window, or double-click on the Sirius Video rectangle to edit Sirius Video attributes; Figure 4-1 shows the window.
| Note: Most features of this window are the same as for channel attributes or Encoder attributes; see the explanations in Chapters 2 and 3 for information. |
Select the output format for Sirius Video from the Output Format popup menu:
525: square pixel 646 x 486 NTSC resolution
625: square pixel 768 x 576 PAL resolution
CCIR601 525: non-square 720 x486 NTSC resolution
CCIR601 625: non-square 720 x 576 PAL resolution
At Pixel Format, select RGBA10 for 10-bit RGB with alpha. This selection presents alpha information for the Sirius Video board.
To genlock the high-resolution channel to the Sirius Video board, click Edit globals... in the Combiner main window, and select a sync source and format, as explained in “Setting Sync Source and Format” in Chapter 2.