Design IPs for Video Wall Player

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Introduction
A video wall is a set of displays is arranged in order to present a single large image or smaller multiple images from an incoming analog or digital signal. Video wall is a cost effective and flexible alternative to a high priced large screen. Video walls are being increasingly used in various markets such as
  • Information/Advertising Display screens in large public areas such as airports, shopping malls
  • Central Monitoring in controls rooms for traffic and security
  • Home theatre system
  • Broadcasting and other Professional Visual use
For a Video Wall Apllication, there is a need of a Video Wall Player, a processing device that is able to receive the incoming analog or digital video data, manage either an interlaced or progressive signal and perform appropriate format transformations as per the required output configuration.
The functionalities of a video wall player are
  • Receiving the video (in some cases it may be static image) from a video source like DVD player, USB pen drive, hard drive etc
  • Decoding and splitting the video as per the input video type, output display type and video wall configuration
  • Up scaling the video to match the resolution of video wall
  • Video conversion to make it suitable to view in the targeted display device
  • Transfer the video to the display
A video wall player is available either as a stand alone system or as a PCB card which can be connected with a PC via a high speed interface like PCI-E. In either case, the Video Wall player is made of one or more than one of the following core components:
  • Standards ASSPs including video decoder chip, TV encoder chip etc.
  • SoC specially developed for the video wall application
  • FPGA with video wall player code
In case of FPGA based video wall player, the core is embedded in the form of bit-stream in the FPGA device. The architecture and interfaces of a video wall player core can vary depending on the features supported by the video wall player, but the typical interfaces as well as architecture of a video wall player are illustrated below
Video Wall Player Core Interface
A typical video wall player core has the following input ports
  • Video Data Input: The video input may come from variety of sources like SD Card, USB storage device, hard drive, DVD player, network etc. The input may also vary in terms of video type and resolution. For example the video may be uncompressed and in RGB or YUV format. It may be also compressed by methods like MPEG2 and MPEG4. The video can be of low resolution (SD resolution) or of high resolution (HD resolution)
  • Input Video Type: The input video type is defined in terms of resolution, frame rate of the incoming video
  • Video Wall Configuration: User needs to define the configuration of the video wall to be used. The configuration includes number of screen in the video wall in ‘x’ and ‘y’ direction as well as resolution of those screen like 480p , 720p or 1080p etc.
  • Output video type: The output video type is defined in terms of resolution, accepted format of the screens which makes the video wall
  • Control signals: The core needs to accept control signal which may indicate any interrupt or change in input video type, input video source etc.
Video Wall Player Core Architecture
A video wall player core typically has the following components
  • USB controller/ SATA controller/ SD card controller in case the video is read from a storage device or HDMI receiver in case the video is accepted from a streaming device
  • A video decoder if the input video is an analog signal coming from equipments like DVD players etc. Most of the cases the analog input video is in either PAL or NTSC format
  • MPEG-2 / MPEG-4/ H.264 decoder
  • De-interlacer in case a interlaced video needs to be displayed in the progressive display (e.g. HDTV) or interlacer in case a progressive video needs to be on interlaced display (e.g. SDTV)
  • Video splitter to split the incoming video frame in multiple video frames to be displayed in multiple displays
  • Up scaler to increase the resolution of the split video frame as par the resolution of display device
  • HDMI transmitter/ HD Encoder/ PAL NTSC encoder based on the display device
  • RS232, RS485 controllers which are basically used for configuring the other modules of the video wall player
Characteristics of a Typical Video Wall Player
The current generation video wall player supports various types of input as well as output video format to enable them to be used with variety of input and output devices. The typical parameters which define the features of a video wall player are
  • Input resolution supported: This parameter specifies the highest resolution of still image as well as video supported by the video wall player. the frame rate of the video supported by the video wall player is also specified. For example a video wall player can support up to 5 MP of still image and 1920 x 1200 @ 60 Hz video. Greater the processing power of a video wall player, higher the resolution of image and video it will be able to support
  • Output resolution and format supported: This parameters specifies what kind of output resolution the video wall player supports and what kind of output format it supports. Today's most of the video wall players are made of HD screen which takes input from HDMI or DVI inputs. Hence in most cases, a video wall player needs to support up to HD resolution (1920 x 1080 @60 Hz) and HDMI and DVI output format.
  • Mode: This parameter specifies the different modes supported by a video wall player. The common used modes in a video wall player are
    • Full Mode: Here the whole video wall display only one image or video and hence the image or video needs to be upscaled if the resolution of the whole video wall player is more than the resolution of the incoming image or video
    • Clone Mode: Here the each screen of the video wall player shows the same image or video
    • Vertical replication: Here the incoming image or video is upscaled only in horizontal direction and the same image or video is replicated in vertical direction
    • Horizontal replication: Here the incoming image or video is upscaled only in vertical direction and the same image or video is replicated in horizontal direction
  • Video Wall Array: This specifies the array of screens that the video wall player supports such as 3x3, 2x3, 3x2, 2x2 etc
  • Special Features: This specifies what other special features the video wall player supports. Some of special features are
    • Intra screen compensation: As the in video wall the screens are tiled there is a gap between two screens in horizontal as well as vertical direction, there needs to be horizontal as well as vertical shift of the spit video/ image to ensure that it appears continuous in the video wall
    • Curvature compensation: In some cases the video wall is not flat one, but a curved one and in those cases the player needs to do curvature compensation of the video
    • Angle compensation: In some cases the video wall is put on a vertical or horizontal angle and in those cases there needs to be angle compensation by the video wall player
SoftJin’s IP Offerings for Video Wall Player
SoftJin offers several key Design IPs that are useful in the Design of a Video Wall Player Core as described above. These verified Design IPs help reduce the time to market for an FPGA or an SoC based Video Wall Player developer. SoftJin also can integrate these internally developed IPs with other third party IPs and license complete video wall player sub-system design. SoftJin’s IPs benefit customer by
  • Reducing the development time by availing a already developed component
  • Reducing the risk of failure by availing a verified (both stand alone and in integrated system) component
  • Reducing cost of development
SoftJin’s Design IPs that are relevant for Video Wall Player include:
  • DVI/ HDMI Rx
  • De-interlacer
  • Interlacer
  • Up scaler
  • DVI/ HDMI Tx
  • Video Splitter
  • PAL NTSC Encoder
  • RS-232/ Rs-485 controller
Features of some key SoftJin IPs
PAL NTSC Encoder
  • Supports BT601 and BT656 input formats
  • Supports NTSC(M), PAL(B,D,G,H,I), PAL (M) and PAL(N) output video standards
  • Supports RGB, YUV, S-Video and Composite output video formats
  • Supports Color Bar mode
  • Supports Ancillary data (WSS and CGMS)
  • Programmable Luma and Chroma filters
  • 2x oversampling of luminance and 4x oversampling chrominance filter for interlace mode
  • Programmable Luma delay
  • APB Interface to Register Set
  • Supports Vertical Blanking Interval (VBI) encoding support including WSS & CGMS Encoding
HDMI Transmitter
  • Support resolutions from VGA to HDTV (640x480, 720x480p, 720x576p, 1280x720p, 1920x1080i)
  • Supports 25-165M pixels/second
  • Interface supports 24-bit RGB, 24-bit YCbCr (4:4:4) and 12-bit YCbCr (4:2:2) inputs
DVI Receiver
  • Support resolutions 640x480p, 720x480p and 720x576p on Spartan3A device
  • Support 24-bit true color pixel format
Up-scaler
  • Linear up scaling in both horizontal and vertical direction
  • Programmable X and/or Y direction scaling factor
De-interlacer
  • Motion Adaptive de-interlacing algorithm for NTSC/PAL video
Video Splitter
  • User configurable video frame splitter as per video wall tile arrangement>
RS485 Transceiver
  • Mode of data transmission and reception namely RTU or ASCII
  • Even, odd, or no-parity bit
  • 1 or 2 stop bits
  • Different baud rates up to 4000K Baud
  • Half duplex communication
FPGA based Video Wall Player
In FPGA based video wall player the all digital modules are implemented on FPGA platform. The advantage of an FPGA based video wall player
  • Single chip solution resulting in compact and high performance video wall player
  • The computational intensive parts of IPs like up-scaler, de-interlacer can be implemented using parallel processing units and hence very large video wall with high resolution can be supported
  • The same video wall player can be used for multiple configurations of screen
  • • Easy to support special features such as Intra screen compensation and curvature compensation by developing customized special function blocks in FPGA
Estimated FPGA chip required for some sample video wall player configurations
Output Format and Resolution
Video wall configuration
Suitable FPGA device
PAL NTSC (interlaced video)
2x2
4x4
Xilinx Virtex4
Xilinx Virtex4
HDMI (720p)
2x2
4x4
Xilinx Spartan3
Xilinx Spartan6
HDMI (1080p)
2x2
4x4
Xilinx Virtex6
Xilinx Virtex6

The IP can be licensed under a single usage license model as well as multi-usage license.

For more information about Video Wall Player IP please click here to download the PDF.

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