evertz hd9084, Инструкция по эксплуатации

Страница: 48 / 126

HD9084 HDTV Caption Encoder Manual
Page 3-18
OPERATION
setup when the encoding to NTSC video takes place, it is necessary to shift the caption data down by
7.5 IRE when generated by the caption encoder. Unfortunately, in order to shift the caption data down
by 7.5 IRE, it is necessary to use digital video values that are not legal according to the SMPTE 125M
Component Digital Video specification. Setup Shift is used to select whether the caption data encoded
on the downstream SDI video will be shifted to adjust for setup on line 21.
0 IRE will encode captions at 0 IRE on 4:2:2 video signals. The resulting closed caption signal will
contain legal SMPTE 125 data values but may have 7.5 IRE of setup added when it is encoded to a
composite video signal. (Depending on the video encoder) -7.5 IRE will encode captions at -7.5 IRE
on 4:2:2 video signals. The resulting closed caption signal will contain illegal SMPTE 125 data values
but may have the 7.5 IRE of setup cancelled out when it is encoded to a composite video signal
(depending on the video encoder).
3.4.2.6. CEA-608 Test Msg
The CEA-608 Test Message is used to test all fields and outputs of the HD9084. This function will
provide test messages in Field 1 and Field 2 for the SD-SDI output and up-converted test messages on
the HD output. The CEA-608 Test Message function will also produce test messages on Ports A, B,
and C, which can be monitored using HyperTerminal. This function will help ensure the HD9084 is
processing all information and is helpful during troubleshooting procedures. Please refer to the testing
section for detailed instructions. Unlike most settings, the CEA-608 Test Message will revert to “Off”
after power is removed from the HD9084.
3.4.2.7. VANC CC Line Sel
The VANC CC Line Select control is used when the user wants to insert CDP data into the VBI of the
SD-SDI output. This feature is typically used in DTVCC transmission to ATSC encoders. This control
selects which line of the VBI the CDP data is to be inserted on. The range of this control includes line
10 to 19 inclusive. Refer to the note following section 3.4.2.8.
3.4.2.8. VANC Keyer Ctrl
The VANC KEYER control is used when the user wants to insert CDP data into the VBI of the SD-SDI
output. This feature is typically used in DTVCC transmission to ATSC encoders. This control enables
or disables the VBI keyer. The possible options include SD VANC KEY OFF and FOLLOW HD
KEYER. Selecting SD VANC KEY OFF will disable the VBI keyer and not encode CDP data into the
VBI of the SD-SDI output. Selecting FOLLOW HD KEYER will enable the VBI keyer. The HD keyer
must also be enabled. Refer to the following subsection.
3.4.2.8.1. VANC Packets in SD-SDI
SD-SDI VANC CDP INSERTER
The CDP frame rate and insert cadence will follow SD-SDI frame rate and timing if HD-SDI video is not
present and SD-SDI video is present. CDP frame rate and insert cadence will follow HD-SDI frame rate
and timing if HD-SDI video is present, or free-run at HD-SDI settings if neither video input video is
present. There may be some combinations of HD and SD video formats that result in CDPs being
inserted onto SD-SDI that are unreadable by downstream equipment.
For example, when HD-SDI video is 1080p/23.98, a CDP will not be inserted for one frame in every 5
frames of the 525i/59.94 SD-SDI, but the amount of data in each CDP will be increased to maintain a
constant throughput.
Some downstream equipment may not be able to handle this condition
properly.
USO
RESTRITO