Applications
Digital Video Recorders (DVRs)
DVRs are used in the CCTV and Security industry to record video captured by security cameras. Video is presented to the DVR from the camera as a Composite analogue video source. This video is digitised using a video decoder chip and then passed to either a multiplexer or directly to a video compression codec. In most cases the multiplexer is used and this either Frame, field or Quad multiplexes the video in order to reduce the amount of disk space required to save the video. Low end DVRs will QUAD the image reducing its resolution by 1/4 but keeping the original frame rate. Higher end systems tend to Frame or Field multiplex which reduces the number of frames and fields stored per camera but maintains the original resolution. Top end systems do not use multiplexers as they store the image at both original frame /field and resolution.
In all cases the video is compressed to save disc space (Hard Disk) by using a video codec/s. Typical codecs are JPEG MPEG4 H264 and in some cases wavelet or other prorietery flavours of compression. Once the video is stored on the hard disc drive in a compressed form it can be replayed using a de compression codec and passed to a display. In many cases the video may be sent compressed via a network for remote viewing.Display processing is another key feature as this allows multiple live or replayed camera images to be displayed on a TV or LCD monitor with information superimposed like time/date/camera number.
Zilica supplies video decoders, multiplexers, Video compression codecs, display processors , complete System on Chip DVR solutions and other key components.
Video Servers and IP cameras
Video servers are the key subsystem that converts an analogue camera into a network camera or also sometimes called anIP camera . The process is simple, analogue video is applied to the video server , compressed using a video codec and then sent out usually over an ethernet connection encapsulated in an IP stream (Internet Protocol). At the other end of the network the video IP stream is decoded using either a PC based system or a dedicated decoder box. This process takes the IP stream , strips out the compressed video and then de compresses the video producing usually an anlaogue video signal. In the case of PC based decoders the compressed video is sent directly to a player application (Quicktime or similar) and this software based codec decompresses the video displaying on the LCD PC monitor.
Zilica supplies the compression and decompression codecs, system on chip solutions which support the TCP IP stack and network interface and also complete video servers as modules.
PCI capture and Compression cards
PCI capture cards basically take analogue composite video from a camera and just digitise it using a video decoder. This digitised video is then converted and applied to a PCI slave interface. Capture cards can have 1,2 4, 8 or 16 channels of analogue video. PCI capture cards are used in PC based DVRs where the PC is used as the compression codec and storage device (hard disc). These systems have a basic limitation that the PCI bus speed can only support about 4-5 raw video channels at any one time. More advanced capture cards will have hardware video compression codecs on board to reduce the data bandwidth on the PCI bus thus enabling many more video cannels to be supported on one PCI bus.
Zilica supports chips for digitising the video, applying raw video to the PCI bus (Bridge chips) and compression video codecs.
Video Conferencing
Video conferencing is similar to the process employed by video servers except the bandwidth of the transmission system is more limited than ethernet (telephone, ISDN etc) The video is compressed using either H263 or H264 video standards and transmitted to another video conferincing unit where the video is decoded and displayed. The process is performed in full duplex mode so that video is sent and recieved simultaneously.
Zilica supplies the H264 H623 video compress codecs that can operate in full duplex mode plus audio.
Video PIR detectors
Video PIR detectors are enhanced versions of the Infra Red detectors used by the majority of burglar alarms . The video versions of these PIR detectors add a camera to capture images when the PIR detector is triggered by movement. These camera images are compressed and either stored on a local flash card or sent to a central storage box elswhere. The video requires compression to reduce storage space on the flash card and bandwidth during transmission..
Zilica offers MPEG4 JPEG and H264 compression solutions for these applications.
PMP Hard Disk personal media players
PMPs are like iPODs and vary in the way video and audio is stored , either flash or hard disk. Another variable is how the video or audio is compressed before storage. Many PMPs require the video and audio to be compressed first using a PC whilst others have built in compression codecs like the Archos devices.
Zilica supplies ultra small low power H264 codecs for the PMPs that require built in compression.