Start your multimedia PMP journey by choosing the right processor

Based on the positive performance of the MP3 audio player market, developers and manufacturers have great expectations for the market prospects of video-enabled portable media players. Consumers are showing interest in personal entertainment centers that integrate audio, video, navigation, gaming and mobile TV functions. With industry analysts predicting strong growth in the market next year, multi-format content support, play time, security, competitive cost and time to market will be the key for developers and manufacturers to achieve the greatest success in this consumer electronics market. Choosing the right processor platform will make a fundamental difference in meeting these challenges.

Hardware Platform Choice

The two common choices for PMP hardware platforms are a microcontroller (MCU) plus a digital signal processor (DSP), or an MCU with a hardware accelerator. These two-chip solutions take up more board space and increase system cost relative to single-chip structures.

Another option is a system-on-chip (SoC) solution that integrates the MCU core and DSP core on a single package. Generally speaking, SoCs take up less board space than MCU+DSP and MCU+hardware accelerator structures. Because the MCU and DSP perform different tasks, two development tool sets and two sets of execution code are still necessary. Complex data exchange and program process collaboration still occurs between the MCU and DSP. Even with this single-chip SoC approach, system-level complexity remains a factor that development and support engineers have to consider.

An alternative is a "convergent" processor that combines the capabilities of an MCU and a DSP. A true convergent processor would be optimized for both computational and control-oriented tasks in real-time multimedia data streams. The high-performance Blackfin processor family from Analog Devices embodies this convergent design. Blackfin is a fixed-point processor that provides MCU and digital signal processing capabilities on a single core architecture, allowing for flexible partitioning of tasks between control and signal processing. The same development environment across the entire Blackfin lineup makes it faster and cheaper to develop and debug PMPs with different feature sets.

Supported Content: Formats and Performance

Like audio, video content is available as unlimited and premium content downloaded from the Internet. Many different media standards, versions, and video formats also exist. So when PMP terminals support different media formats and other value-added features such as Wi-Fi, mobile TV, and gaming, the potential content is fully expanded. Transcoding is another useful attribute, and is necessary, so that downloaded videos can be converted directly to a format that can be viewed on the PMP without having to be transcoded on the PC.

However, compared with MPEG-2/4, other algorithms such as RMVB, Flash, H.264 and AVS are more complex and consume more processor performance.

Existing commercially available SOC solutions have limited processing power (MCU operates at around 100MHz, DSP does not exceed 150MHz). When complex algorithms and functions exceed the capabilities of the currently selected SOC, moving to a different processor is the only viable option.

For MCU+hardware accelerator solutions, system performance is mainly determined by the capabilities of the hardware accelerator. And the development of hardware accelerators is difficult to keep pace with the ever-changing media formats. With

an operating frequency of up to 600 MHz (1.2GMMACS), Blackfin's converged processing structure provides ample computing performance to handle complex algorithms and functions. Because Blackfin also brings real-time signal processing and high-definition video encoding and decoding, multiple audio and video formats and rich peripherals. Developers can implement PMP designs that support different media formats and functions by simply modifying the software. Because Blackfin supports software programmability, developers can also incorporate updated media formats and standards.

As social networks become more popular, consumers want to share audio and video on their PMPs. (Of course, copyright and licensing requirements apply.) In addition to its media processing capabilities, Blackfin provides enough performance to incorporate a wireless protocol stack and peripherals for handling Wi-Fi connectivity and Internet user interfaces.

Portability: Size and Power Management

Form factor and power consumption constraints imposed on developers in multimedia players are more stringent than those imposed on MP3 audio players and cell phones.

Peripheral integration is a strong feature of the Blackfin processor. By providing a high-performance core with industry-standard interfaces, Blackfin saves board space and minimizes expensive external components. Development is streamlined because developers do not have to spend any time integrating the USB 2.0 high-speed OTG controller, NAND flash controller, UART, SPI, serial ports, DMA master interface and parallel peripheral interface.

Power consumption is a barrier in PMP design. Because multimedia features and network connectivity consume more power, consumers want longer playback time and smaller product size and weight. To extend battery life and reduce power consumption, chip manufacturers typically reduce the processor's core frequency to match the data flow processing requirements. As the increasing number of PMP functions creates greater and more variable demands on processing performance and therefore power, static power management becomes relatively inadequate. Milliwatt (mW) per megahertz (MHz) optimization is necessary for longer standby and play time.

Blackfin uses dynamic power management to adjust core frequency and voltage to optimize performance at lower power. Blackfin can operate in five power modes—full speed, active, sleep, deep sleep and hibernate—each providing different power/performance performance. In each mode, an internal regulator intelligently manages the voltage to minimize power consumption. The power consumption and performance ratio can reach 0.16mW/MHz at 250MHz core voltage.

Security: A common topic

Security has become a focus of the industry as PMPs continue to grow in network connectivity, gigabytes of storage and portability. Solution providers and manufacturers want to protect their intellectual property such as drivers, operating systems and user interfaces. Content providers may refuse to license their media content unless its digital rights management (DRM) is secure. Personal data protection and device authentication also become considerations as social networks evolve to include video sharing and e-commerce.

Although there are many data security methods, a common feature is that security is often designed in late. Two popular approaches are software encryption or packaging. This software-only approach may be based on the operating system's separation of secure and non-secure environments. These methods can be easily defeated by software and hardware attacks, using hardware emulators or software injection. One method to protect DRM keys is to use software to hide private resources, but this can also be defeated by memory analysis.

Combination passwords inserted in trusted modules are another commonly used data security technique. However, hackers can still obtain private resources by monitoring the bus and launching software attacks when data is moved out of the trusted module, or when data is read from or written to the trusted module.

Stronger protection can be achieved by designing security from the beginning, using both hardware and software to ensure the confidentiality and integrity of secure resources including keys, code and data. With Blackfin's Lockbox security technology, solution developers can also choose to use standard algorithms to verify digital signatures and use a secure processing environment to run code and protect resources. Access to the secure area is monitored by hardware.

And, with Lockbox security technology, developers can use the unique chip ID on each Blackfin processor to uniquely identify each device. This unique chip ID can be used with trusted DRM agents to enforce rights renewal or revocation. Another possibility is to use the chip ID to blacklist OEM devices when security is compromised. This unique chip ID can also be used to bind a processor to a specific boot code to prevent the device from being cloned.

Cost: Bill of Materials and Development

If PMPs continue to follow the trends of other consumer electronics products, they will implement more features at lower prices in the coming years. As a result, developers and manufacturers will pay more attention to cost and time to market.

The processor itself is not the largest contributor to cost, the required software development also has a considerable impact - costs can be reduced through the use of development tools, reference designs and third-party software. The increasingly short PMP product life cycle also means compressed development cycles for solution developers. Development can be accelerated through the peripherals integrated into the processor and development support.

In such two-chip processor platforms (MCU + DSP or MCU + hardware accelerator) and classic system-on-chip (SOC) platforms, the functions of MCU and DSP are still differentiated by separate tool chains and software development environments. Blackfin, as a convergent processor, provides a way to work on a single processor and a unified tool chain.

Moreover, software programming performance and peripheral integration make it possible to add new functions without any increase in bill of materials cost. Product and feature differentiation is faster because developers can focus on their application software while also taking advantage of highly optimized audio and video algorithms developed by ADI and software modules and reference designs provided by third parties.

This article summarizes

that multimedia processors with video have raised the design requirements of PMPs, increasing the requirements for multi-format media support, high performance, power management and security. For solution developers and manufacturers that go beyond MP3 players that only support audio, grasping market demand can start with choosing a suitable processor.