While designing, it is critical to pick the appropriate codec or formats that can be handled by a video IP to support any given application. It is also very important to select the correct video IP with proper and standard interfaces so that it can be as close as possible to 'plug-and-play' in terms of System on a Chip (SoC) integration.
Ravishankar Ganesan, VP, SoC IP Business Unit, Ittiam Systems, commenting on the selection of the video IP for SoC designs, said that SoCs use the divide and conquer strategy very well.
The SoC is today truly defining and integrating multiple specialized blocks or subsystems keeping the target application of the SoC in mind. Each one of these specialized subsystems needs to be the best in terms of its performance, area and power so that the SoC can be the best, competitive and well suited for the target market.
The video intellectual property (IP) is one of these specialized subsystems, and hence, critically important for SoCs, which are targeted for video based applications. Needless to mention, there is no one video IP that 'fits all' video SoCs.
So what should any SoC designer look for in terms of supporting video profiles and codecs? This really depends on the application(s) for which the SoC is likely to address. If you are targeting video IP for mobile TV application in a cellular phone, the profiles and codecs will get determined by the appropriate broadcasting system.
Similarly, if the SoC is targeting the high-definition ((HD) DVD player segment, the video codecs and their profiles/levels needs to be determined based on the video encoder configuration that was used to create the content on the DVD disc.
There has to be a way on going about selecting/understanding video codecs. In this context, it is very critical to pick the appropriate codec or formats that can be handled by the video IP to support the given application.
It is also very important to pick the video IP with the proper and standard interfaces so that it can be as close as to "plug-and-play" in terms of the SoC integration. The area and power dissipation are important as well, so that the SoC can be sold at a competitive price in the market.
At high pixel rates, what would be the situation with the video subsystem? Simply put, the higher resolutions result in the explosion of data. The video subsystem needs to be highly efficient in order to handle the high data movement. It also needs to have very efficient video processing engines to meet the real-time requirements.
As for the amount of off-chip video bandwidth that is actually needed by an IP block, Ganesan said that it depends a lot on the resolution that the video IP is likely to handle. The video resolution, profiles and levels will get determined by the application. Trade-offs between silicon real-estate and off-chip video bandwidth plays very critical role.
Improving video performance
Video performance is said to deteriorate as the off-chip memory latency increases. What can be done to improve this? Internal buffering will definitely help to reduce this impact. However, that can affect the silicon size of the device. Hence, care needs to be taken and trade-off needs to be done depending upon the Video system requirements.
Finally, let's examine how best can a designer integrate the video IP core into an SOC design. Depending upon the interfaces, the video IP can slide easily into the SoC. The IP could be just an engine, or processor core based soft IP or a combination of both.
So, the SoC designer needs to evaluate the application requirements, and determine the right interfaces and the appropriate processor core, along with the memory sub-system. There could be peripheral interface IPs [that are either part of the Video IP or separate], which also needs to be inserted as part of the SoC and the data flow on the device needs good management.