VideoCore
VideoCore is a low-power mobile multimedia processor architecture originally developed by Alphamosaic Ltd and 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 I-based VC01 provides video and multimedia capabilites to various Samsung phones, including SCH-V540, SCH-V4200, SCH-V490 [2]
The VideoCore II-based VC02 / BCM2722 processor provides video capabilities for Apple's 5th generation iPod.[3]
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. It is used in the Nokia 808 PureView.[4]
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Multimedia system constraints [edit]
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.
VideoCore key features [edit]
- Instruction set written with video processing in mind from the start. For example, saturation arithmetic so that the sum of two bright pixels does not 'wrap around' into dark values.
- An array of graphics processing units for parallel computing of video data at relatively low clock speed
- Very high integration puts CPU, GPUs, memory and display circuitry on a single chip, removing the power burden of driving fast off-chip buses.
VideoCore ICs [edit]
| Device | GPU | CPU | Max display | Notes |
|---|---|---|---|---|
| VC01 | VideoCore 1 | none | CIF | Samsung SCH-V490, Samsung SCH-V420, Samsung SCH-V450, Samsung SCH-V4200, Samsung SCH-V540, Samsung SCH-X699, |
| BCM2702 (VC02) | VideoCore 2 | none | SD PAL/NTSC | TCL D308, TCL D918, Samsung SPH-B3100, Samsung SPH-P730, Sandisk v-mate, BenQ S700, O2 X3, Nintendo Play-yan, Sagem MyMobileTV, |
| BCM2705 (VC05) | VideoCore 2 | none | SD PAL/NTSC | |
| BCM2722 | VideoCore 2 | none | SD PAL/NTSC | Apple's 5th generation iPod |
| BCM2724 | VideoCore 2 | none | SD PAL/NTSC | |
| BCM2727 | VideoCore 3 | none | HD 720p | Nokia N8 |
| BCM11181 | VideoCore 3 | None | HD 720p | |
| BCM2763 | VideoCore 4 | none | Full HD 1080p | Nokia 600, Nokia 700, Nokia 701, Nokia 603, Nokia 808 |
| BCM2820 | VideoCore 4 | ARM1176 | Full HD 1080p | |
| BCM2835 | VideoCore 4 | ARM1176 (700 MHz) | Full HD 1080p | Raspberry Pi,[5] Roku 2 [6] |
| BCM11182 | VideoCore 4 | None | Full HD 1080p | |
| BCM11311 | VideoCore 4 | ARM Cortex-A9 dual core | Full HD 1080p | |
| BCM21654 | VideoCore 4 | ARM Cortex-A9 + ARM Cortex-R4 |
Full HD 1080p | |
| BCM28150 | VideoCore 4 | ARM Cortex-A9 dual core | Full HD 1080p | Aimed at 3G baseband processing, powerful enough to run Android OS. |
| BCM21553 | VideoCore 4 | ARM11 Compatible ARMv6 Based on ARM Cortex-A9 | Full HD 1080p | Samsung Galaxy Y[2][3][4] Samsung Wave Y, Samsung Galaxy Mini (GT-S5570i), Samsung Galaxy Ace (models 5830i/c/m and 5839i),Samsung Galaxy Ch@t (GT-B5330), Vodafone Smart 2 (Alcatel TCT V860),Samsung Galaxy Gran Duos I9082 |
VideoCore products [edit]
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).[citation needed]
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.
Market competitors [edit]
Similar mobile multimedia chip ranges include Texas Instruments OMAP, Nvidia Tegra, AllWinner A1X and Freescale i.MX. These four are ARM-based with arrays of Graphic Processing Units.
Data sources [edit]
The Broadcom YouTube page [7] 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.
References [edit]
- ^ Alphamosaic Ltd > Technology – VideoCore, archived on 9 February 2003.
- ^ [1]
- ^ Ars Technica: Video iPod – Vivisection, accessed on 29 March 2008.
- ^ http://www.staygrab.com/nokia-808-pureview/
- ^ Raspberry Pi - FAQ
- ^ Engadget - Roku 2 line passes through the FCC with modest hardware updates and a reset button
- ^ Broadcom YouTube page
