Internal Modules
123
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
1.2.6.2.10 Closed Caption
The VENC supports closed caption encoding. Closed caption data is transmitted on the line 21 of the odd
(top) field and the line 284 of the even (bottom) field in 525i mode. It is possible to specify the fields on
which closed captioning is enabled by L21EN register.
Closed caption encoding for 625i system is also supported. Closed caption is inserted on line 22 of the
odd field and line 335 of the even field for 625i systems.
The data should be written to the L21DO or L21DE register for odd or even fields, respectively. When data
is written to L21DO, CAOST read status bit is changed to 1. When data is written to L21DE, CAEST
becomes 1. These bits are automatically cleared to 0 when a caption data transmission is completed on
the line 21 in odd field or the line 284 in even field (line 22 and 335 for 625i).
When the caption data register (L21DO or L21DE) is not written before the caption data transmission
timing of the corresponding field, an ASCII code specified by L21DF register is used for transmission. A
null character should be typically set to L21DF register.
The width of each data register is 8 bits, which consists of 7-bit data and the parity bit. It is your
responsibility to calculate the parity bit. The amplitude of closed caption pulse is automatically determined
as 50% of white (50IRE).
1.2.6.2.11 Raw VBI-data Insertion Mode
The VBI waveform which is not supported by VENC hardware can be inserted using raw VBI-data
insertion mode. In this mode, the VBI waveform is synthesized by software according to the waveform
requirements of the selected data type. The VBI_IF module sends VBI waveform to the VENC at the
specified VBI lines.
The raw VBI-data insertion mode is enabled VBIEN register is set to 1. Otherwise, the VBI_IF module is
basically in a reset state.
The VENC asserts venc_vbi_req pulses to the VBI_IF module during VBI period. The horizontal timing of
venc_vbi_req can be configured by VBI_H_STA and VBI_H_STP registers. The reference timing of these
registers is the internal TV counter. The vertical timing is determined by the AV window position which is
specified by AV_V_STA and AV_V_STP registers. The timing is shown in
and
The VBI_IF module keeps tracks of VBI line numbers by counting the number of venc_vbi_req pulses. On
the specified VBI line number, the VBI_IF will send the samples from the payload to the VENC with
vbi_venc_val set to HIGH. The data width of vbi_venc_data is only 8bit so zeros are padded to the 4 LSBs
when inserted.
Note that CC/WSS and Macrovision have the priority over the VBI data when VBI data insertion is
activated on the lines which have these pulses. The vbi_venc_val is disregarded at the lines CC/WSS and
Macrovision are enabled.
1.2.6.2.12 Macrovision
The VENC supports analog copy protection Macrovision Rev7.1 to the SDTV CVBS and S-Video output.
Due to strict security control by Macrovision, any information such as Macrovision register map, usage,
and so on, are not directly distributed to the customers. These information are supposed to be given by
Macrovision upon a certain certification.
1.2.6.2.13 Register Setting for Various Video Standards
is a list of the typical register setting for various video standards.
