2/24/2008 9T6WP
BCM7405
Preliminary Hardware Data Module
Functional Description
06/29/07
Bro a d c o m C o rp o r a ti o n
Page 1-36
Video and Graphics Display
Document
7405-1HDM00-R
V
IDEO
AND
G
RAPHICS
D
ISPLAY
O
VERVIEW
The video and graphics module accepts decoded AVC/MPEG/VC-1 or analog video and performs professional quality
compositing of text and graphics with video. The video subsystem takes in uncompressed video from either the AVC/MPEG/
VC-1 decoder or the digital ITU-T-656 input. The subsystem processes the input videos based on the input and output
format, and system requirements. It can be scaled and converted to the output display format directly, or go through single
and multiple capture and playback loops. Each capture and playback loop could involve data processing like DNR, MAD-IT,
or scaling.
Two independent video streams (one stream must be limited to SD stream) can be processed at the same time and
converted to different size and format. Finally, they can be blended together as PIP (picture in picture) windows or drive up
to two separate displays. Both displays may have separate graphics inputs to blended with. The architecture allows users
to create a series of frame-buffers that allow an unlimited number of graphics layers to be composited and blended together
before being displayed.
Once the graphical frame-buffers are available, they can be combined with the video using a new compositor. This new
compositor allows up to two video surfaces to be combined with a graphical surface (frame-buffers). The blending order of
any surface is controlled by software to allow the utmost flexibility for the end-user.
The graphic surface generation is now divorced from the real-time display requirements of the video output. Once the new
graphics surface is available, it can be switched in for display. Therefore, all of the graphics development interacts only with
the memory—not with any of the display hardware.
The architecture goal of this new, modular approach is to allow various chip-sets to share the same basic component building
blocks to achieve the customers design requirements. The BCM7405 employs enough of these building blocks to realize a
dual video output with independent graphics on each output. Supported video decode and display format combinations can
be seen in
.
Features
•
ITU-R-656 digital video input, ancillary data, Teletext, close caption, NABTS, WSS, CGMS-A, Gemstar pass-through
support
•
DVI Video output
•
Capable of simultaneous HD/SD output with independent graphics for each port
•
Orthogonal configuration for programming features
Video Subsystem
The Broadcom Video Network (BVN) video subsystem consists of the following components:
•
Digital Noise Reduction Filter
-
Reduces MPEG artifacts, including block noise
-
Reduces mosquito noise
•
Digital Contour Removal
•
AVC/MPEG/VC-1 feeders, handling the YUV4:2:0 data format
•
Graphics feeders, handling YUV4:2:2 and RGB data formats
•
Video feeders, handling YUV4:2:2 data formats