MICROTRONIX DX-2200-SW-02, Руководство пользователя

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DX-2200
– Dual-view 2x1 SDI Video Switcher
Page 52 of 87
Frame Counter Modes 2, 3, and 4 display the frame count as a four
digit “NNNN”,
a six
digit “NNNNNN”, or an eight digit “NNNNNNNN” number with leading zeroes.
The count increments on every output frame and will reset to 0 when all digits are
‘9’.
Commands are provided to configure the position and color of the Frame Counter
and to set the current count to a specific value. The current frame count value for
Mode 1 can be set using the ‘SFT:HH:MM:SS’ command. The current frame count
value used in Modes 2, 3 and
4 can be set by the ‘SFNnnnn’ command. The two
count values are independent of each other. Both counters start at zero when the
DX-2200 is powered on or reset. The frame counts continue to be updated when
the counter is not displayed for progressive video formats.
The syntax for many of the Frame Counter Commands (see Table 15) is similar to
that used by the Text Overlay Commands but there are also important differences.
Many commands include a string number. String number may be either one or two
digits, for example ‘01’ or ‘1’. At present there is one text field supported by the
frame counter and the string number should always be set to 1. Other values are
reserved for future use. The string numbers used by the Frame Counter
commands are independent of those used by the Text Overlay.
To support high speed (frame rate) operation, the frame count is drawn directly
into the active text overlay buffer. (See ‘Low Level Text Control Commands’ for
more information). A consequence of drawing to the active buffer is that the
number of pixels drawn should be kept small so that the text is drawn within the
time of one frame, otherwise one or more frames will be generated with partially
draw text.
The fonts used by the Frame Counter are not the same as those used in the Text
Overlay. All fonts are fixed width and hard edge. Setting the font to 0 selects a
video mode dependent default font. Other font settings are listed in the command
table. To ensure the frame counter is drawn at the video rate, it is recommended
not to use a font larger than the default font.
The automatically updating Frame Counter modes continuously overwrite the
same location in the video. When the frame counter is turned off, or when the font,
size, or position is changes, the frame count is drawn once with the alpha set for
full transparency. This erases the frame count text from the video and a frame will
be displayed without the frame count before the counter appears with the new
settings.
If the Frame Counter is set to Mode 0 and is being manually controlled, the
‘SF1D’
command is used to draw the text with the specified color and transparency and
the
‘SF1H’ command is used to erase the text by drawing over it with 100%
transparency. If a Text Overlay command causes the two text memory buffers to
be swapped, the text written by the Frame Counter will not be automatically
written to the new memory
buffer. To display the text again, the ’SF1D’ must be
used to redraw the text in the new active buffer.