Nodinfo Networked Digital Video Recorders Draw on Blackfin® for Surveillance

Beijing Nodinfo Technology, Inc (Nodinfo) is a leading domestic provider of networked multimedia management solutions that enable remote monitoring and security surveillance. The China-based company's family of network digital video recorders (DVRs) are typically used for general surveillance, but the products can be specifically targeted at vertical surveillance applications such as coal mining, water conservancy, education, banking, and hospitals.

As still-image, digital video, and audio data rates are large and would otherwise consume a lot of bandwidth to transfer via the Internet, video/audio compression/de-compression (CODEC) standards that allow information to be transmitted and stored efficiently are essential. In the past, analog-recording technologies (based on VHS) had no remote transfer capabilities, no motion-analysis intelligence, and were strictly a one-recorder-per-camera affair. Costs and real-estate requirements for such systems scaled up linearly with each additional camera. Today, self-contained surveillance systems based on network DVRs have become mass-market commodity items. To that end, Nodinfo's primary focus has been on the research and implementation of standard video/audio CODEC algorithms. (See sidebar.)

When Nodinfo was in the development phase of its new NOD3001E network DVR, the company looked for a signal processor that could handle the application's rigorous demands. In the past, the company had used a Texas Instruments C5000 series processor, but new research pointed Nodinfo to a Blackfin® ADSP-BF532 processor from Analog Devices, Inc. (ADI). Nodinfo said the 400 MHz Blackfin ADSP-BF532 processor gave them more performance for less cost than the competition. Plus, the industry-standard interfaces Nodinfo required for the NOD3001E were integrated in the Blackfin device.

Nodinfo's Network DVR
Nodinfo's NOD3001E is a one-channel video/audio network DVR system. In addition to the Blackfin ADSP-BF532 processor, it includes an Ethernet interface, memory controllers, RS-232, RS-422, and RS-485 serial ports for IP cameras and other peripherals, support for MPEG-4, G.726, and G.711 video/audio CODEC algorithms, both IDE and USB interfaces for hard drives, and interfaces for an LCD monitor and a keyboard. The NOD3001E network DVR records up to 25 frames per second (fps) PAL and 30 fps NTSC in real time. The product supports Digital (D1), Common Image Format (CIF), and Quarter CIF (QCIF) resolution video formats.

Support for high-end surveillance scenarios is a key market enabler for the NOD3001E network DVR, and the device features motion detection and will notify the police of intruders via the Internet. The system also includes DVR software and optional IP cameras.

Blackfin Ideal
The Blackfin ADSP-BF532 processor was an ideal choice for Nodinfo for a number of reasons. The processor is based on a Micro Signal Architecture, which combines a dual MAC state-of-the-art signal-processing engine, the advantages of a clean, orthogonal RISC-like microprocessor instruction set, and Single-Instruction, Multiple Data (SIMD) multimedia capabilities into single instruction architecture. The combination of Blackfin's horsepower and the fact that the processor contains two multiplier/accumulators (MACs), two 40-bit ALUs, four video ALUs, and a single shifter allows for very efficient processing of industry-standard video CODEC algorithms such as JPEG, MPEG, Windows Media, and H.263/264 in a variety of screen sizes and frame rates.

As mentioned earlier, Nodinfo chose the Blackfin ADSP-BF532 particularly for its industry-standard peripherals, which enabled Nodinfo to develop its cost-effective solution quickly and effectively without the need for costly external components. In fact, Nodinfo said it was able to complete the first demo unit of its NOD3001E server in just 29 days, which was, in part, due to the excellent support that the company received from ADI.

The Blackfin ADSP-BF532 system peripherals include a UART port, a SPI port, two serial ports (SPORTs), four general-purpose timers (three with PWM capability), a real-time clock, a watchdog timer, and a parallel peripheral interface. This set of functions satisfies a wide variety of typical support needs and is augmented by the system expansion capabilities of the part. The system's high-speed serial ports interface to a variety of audio CODEC functions.

Nodinfo also praised the Blackfin ADSP-BF532 processor's memory capacity. The processor has three blocks of up to 148kb of on-chip memory, providing high bandwidth access to the core.

The first block is L1 instruction memory, consisting of up to 80kb of SRAM, of which 16kb can be configured as four-way set-associative cache. This memory can be accessed at full processor speed. The second on-chip memory block is L1 data memory, comprising up to two banks of 32kb each. Offering both cache and SRAM functionality, this memory block can be accessed at full processor speed. The third memory block is a 4kb scratchpad SRAM that runs at the same speed as the L1 memories, but is only accessible as data SRAM and can't be configured as cache memory.

To enable efficient management of the project from start to finish, Nodinfo used ADI's VisualDSP++, an easy-to-install and easy-to-use integrated software development and debugging environment (IDDE). VisualDSP++ allows users to move quickly between editing, building and debugging activities. It includes the native C/C++ compiler, advanced graphical plotting tools, statistical profiling, and the VisualDSP++ Kernel (VDK), which allows a user's code to be implemented in a more structured manner. It also includes an assembler, linker, libraries, splitter, simulators, emulator support, and more.

Nodinfo also used ADI's Joint Test Action Group (JTAG) ICE emulator to test, debug, and diagnose its hardware through the JTAG access port. Nodinfo was able to run and halt the processor remotely, reading both internal and external processor memory, setting breakpoints for testing.

One thing is for sure: Nodinfo is sold on ADI's Blackfin processors. The company says it is especially interested in higher performance Blackfin processors for future product updates. That's because the Blackfin family offers the price/performance, interfaces, and ease-of-use Nodinfo must have to ensure fast time-to-market for its competitive line of products.

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