saa7130hl-v1 NXP Semiconductors, saa7130hl-v1 Datasheet - Page 26

• Manufacturer Part Number: saa7130hl-v1
• Description: Pci Video Broadcast Decoder
• Manufacturer: NXP Semiconductors

Philips Semiconductors
SAA7130HL_4
Product data sheet
6.6.7 VBI data
6.6.8 Signal levels and color space
The Vertical Blanking Interval (VBI) is often utilized to transport data over analog video
broadcast. Such data can closely relate to the actual video stream, or just be general data
(e.g. news). Some examples for VBI data types are:
This information is coded in the unused lines of the vertical blanking interval, between the
vertical sync pulse and the active visible video picture. So-called full-field data
transmission is also possible, utilizing all video lines for data coding.
The SAA7130HL supports capture of VBI data by the definition of a VBI region to be
captured as raw VBI samples, that will be sliced and decoded by software on the host
CPU. The raw sample stream is taken directly from the ADC and is not processed or
filtered by the video decoder. The sampling rate of raw VBI can be adjusted to the needs
of the data slicing software.
Analog TV video signals are decoded into their component luminance and color difference
signals (YUV), or in their digital form Y-C
line (corresponding to a sampling rate of 27 MHz divided by two), and a certain
relationship from level to number range; see
The video components do not use the entire number range, but leave some margin for
overshoots and intermediate values during processing. For the raw VBI samples there is
no official specification how to code, but it is common practice to reserve the lower quarter
of the number range for the sync, and to leave some room for overmodulation beyond the
nominal white amplitude; see
The automatic clamp and gain control at the video input, together with the automatic
chroma gain control of the SAA7130HL, ensures that the video component stream at the
output complies with the standard levels. Beyond that additional brightness, contrast,
saturation and hue control can be applied to satisfy special needs of a given application.
The raw VBI samples can be adjusted independent of the active video.
The SAA7130HL incorporates the YUV-to-RGB matrix (optional), the RGB-to-YUV matrix
and a three channel look-up table in between; see
RGB space will use the same number range as defined by the ITU and shown in
Figure 11
•
•
•
•
•
•
Closed Caption (CC) for the hearing impaired (CC, on line 21 of first field)
Intercast data in US coded in North-American Broadcast Text System (NABTS)
format, in Europe in World Standard Teletext (WST), to transmit internet related
services, optionally associated with actual video program content
Teletext, transporting news services and broadcast related information, Electronic
Program Guide (EPG), widely used in Europe (coded in WST format)
EPG, broadcaster specific program and schedule information, sometimes with
proprietary coding scheme (pay service), usually carried on NABTS, WST, Video
Programming Service (VPS), or proprietary data coding format
Video Time Codes (VTC) as inserted in camcorders e.g. used for video editing
Copy Guard Management System (CGMS) codes, to indicate copy protected video
material, sometimes combined with format information, Wide Screen Signalling
(WSS)
for luminance, between 16 and 235. As graphic related applications are based
Rev. 04 — 11 April 2006
Figure
12.
B
-C
R
Figure
. ITU-R BT.601 defines 720 pixels along the
Figure
11.
13. Under nominal settings, the
PCI video broadcast decoder
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
SAA7130HL
26 of 46