VideoCore is a low-power mobile multimedia processor architecture originally developed by Alphamosaic Ltd, now owned by Broadcom. Its two-dimensional DSP architecture makes it flexible and efficient enough to decode as well as encode a number of multimedia codecs in software, while maintaining low power usage.[1]
The VideoCore II-based BCM2722 processor notably provides video capabilities for Apple's 5th generation iPod.[2]
The VideoCore III-based BCM2727 processor provides video, still and 3D graphics capabilities for the Nokia N8.
The VideoCore IV BCM2763 processor improves on the VideoCore III with support for 1080p encode and decode, along with higher resolution camera support and faster 2D and 3D graphics, all at very low power.
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Mobile multimedia devices require a lot of high-speed video processing but at low power for long battery life. The ARM processor core has a high IPS per watt figure, and thus dominates the mobile phone market, but requires video acceleration coprocessors and display controllers for a complete system. The amount of data passing between these chips at high speed results in higher power consumption. A single processing unit has to be clocked very fast for video processing, and power is proportional to clock speed, so a single-processor solution will be power hungry.
| Device | VideoCore | 2nd core | Max display | Notes |
|---|---|---|---|---|
| BCM2702 | 2 | none | SD PAL/NTSC | |
| BCM2705 | 2 | none | SD PAL/NTSC | |
| BCM2722 | 2 | none | SD PAL/NTSC | Apple's 5th generation iPod |
| BCM2724 | 2 | none | SD PAL/NTSC | |
| BCM2727 | 3 | none | 720P | Nokia N8 |
| BCM2763 | 4 | none | 1080P | Nokia 600, Nokia 700, Nokia 701 |
| BCM2820 | 4 | ARM1176 | 1080P | |
| BCM2835 | 4 | ARM1176 (700 MHz) | 1080P | Raspberry Pi prototype,[3] Roku 2 [4] |
| BCM21654 | 4 | ARM9 + ARM Cortex R4 |
1080P | |
| BCM28150 | 4 | ARM9 dual core | 1080P | Aimed at 3G baseband processing, powerful enough to run Android OS. |
| BCM70010 | 1080P | AVC/VC-1/MPEG PCI Express HD Decoder Chipset for Netbooks/Nettops | ||
| BCM70012 | 1080P | AVC/VC-1/MPEG PCI Express HD Decoder Chipset for Netbooks/Nettops | ||
| BCM70015 | 1080P | AVC/VC-1/MPEG PCI Express HD Decoder Chipset for Netbooks/Nettops [5] |
VideoCore chips can run complete applications - they are not simply video DSP chips that require a separate processor to supply and collect data. In practice they are often used like this, as companies usually prefer to cautiously assimilate new technology rather than take a big risk in porting a large amount of application code from an existing ARM-based design. The Apple video iPod is a good example of this approach.
Low-power laptops use low-power processors and graphics chips, and therefore often struggle to play video at full frame rates. It isn't desirable or practical to port Windows onto a VideoCore chip, so only the video decoding need be offloaded onto a video accelerator board (e.g. using the BCM70015 chip).
Blu-ray players can also use it as a low-power video accelerator.
Noting that VideoCore chips were usually used with ARM-based chips, the latest chips have VideoCore and ARM processors.
Similar mobile multimedia chip ranges include Texas Instruments OMAP and Nvidia Tegra. These two are ARM-based with arrays of Graphic Processing Units.
The Broadcom YouTube page [6] has videos demonstrating the video processing capability, but their website only goes as far as providing product briefs. Detailed data and development tools are only available under NDA, and then only for manufacturers with a market for very many units.