4,8 and 16-channel PC-based video surveillance and DVR design using PCI or PCIe bus

Today's video-capture systems make extensive use of the conventional 32-bit PCI interconnect, since low-cost PC platforms with PCI video cards enable system designers to create powerful systems using off-the-shelf building blocks. This not only lowers cost, but also enables designers to reduce the time to market, and lower the risks associated with proprietary architectures. But like so many other designs based on conventional PCI, video-capture systems are migrating to the newer and far more powerful PCI Express (PCIe) interconnect standard to help achieve lower cost per channel and higher bandwidth on each card's I/O segment. This bandwidth increase is necessary to accommodate the increased number of video channels, to allow increased image resolution, and to add audio to the streams from each channel as well.

This market dynamic is driving single-channel video cards to be replaced by multi-channel designs. Dual, quad, octal and even higher video channel count solutions are hitting the market. The deployment of several channels of video capture on a single board helps to increase the density of the video processing, lowering cost and reducing the space required for surveillance systems. This in turn increases the bandwidth required of the data stream and can result in a reduction in resolution when there is insufficient bandwidth on the I/O channel. PCIe brings the potential for significantly wider I/O bandwidth -- up to 32 times that of PCI. This, along with the move toward standardization of PCIe on lower-cost PC platforms, is driving the replacement of PCI and other I/O standards with PCIe.

This article explains how to increase the video capture system channel density through PCI and PCIe bridges and switches. Several examples of increasing channel count are used to illustrate:

1 - Using a synchronous PCIe-to-PCI (P2P) bridge to migrate a design from one channel to four

2 - Migrating a four-channel design into eight channels using a P2P bridge with enhanced bus arbitration

3 - Migrating a PCI-based design into PCIe by replacing a PCI-to-PCI bridge with a P2P bridge in forward mode

4 - Connecting an FPGA-based video encoder to a PCIe link via a local-bus-to-PCIe bridge

5 - Developing a 16-channel DVR card using quad-PCI capture chips

6 - Developing a 16-channel capture card using a PCIe switch

Next: Combining four PCI-based video capture processors on a single card using a P-P Bridge