SDVO
Encyclopedia
Serial Digital Video Out (SDVO) is a proprietary Intel technology introduced with their 9xx-series of motherboard chipsets.
SDVO makes it possible to use a 16-lane PCI express
slot to add additional video signalling interfaces such as VGA
and DVI
monitor outputs, SDTV
and HDTV
television outputs, or TV tuner inputs to a system board containing an integrated Intel 9xx-series graphics processor.
SDVO adaptor cards are variously designated as ADD2 (advanced digital display, second generation) or the more feature-rich MEC (media expansion card). MEC is sometimes designated as ADD2+ in Intel documents.
Intel often refers to SDVO as Serial DVO to distinguish it from other forms of digital video out associated with prior product generations, such as the AGP
implementation of DVO and older AGP-style ADD expansion cards which are not SDVO compatible.
According to the Intel patent application, the PCI Express standard lacks a "mechanism to make use of a digital display codec using the PCI Express connector." This limitation is attributed to PCI Express defining only a fixed-frequency interface with significant packet encoding overheads, whereas "digital displays need to have variable clocking and transfer rates and need very little overhead for the transfer of video data".
The patent relates a "presence detect" mechanism to detect SDVO-type expansion cards and enable a pin-remapping of the PCI Express socket to convey SDVO signals.
As of January 2007, Intel has not publicly documented an intent to promote SDVO as an industry standard, despite its potential applicability to any PCI express platform with an Integrated Graphics Processor (IGP), or the desirability from the consumer perspective that SDVO adaptor cards be compatible and freely interchangeable among all such systems.
Instead, Intel is actively promoting the development of SDVO drivers across the broad range of operating systems which run on the Intel 9xx platform. In particular, Intel has established the website intellinuxgraphics.org to promote a fully open source
d drivers supporting all video technologies embodied in their 9xx-series platform.
The upshot is that SDVO cards are compatible with a narrow range of Intel-only hardware platforms, but a broad range of software environments within that platform.
card, allowing video connectors to be added or exchanged at low cost. SDVO adaptor cards can be designed for the following purposes (from Intel ADD2 quoted verbatim):
Older ADD cards were AGP
-based and did not provide a standard interface, posing difficulties for driver development. The second generation ADD2 cards are PCI express and employ a standard interface. There are, however, two distinct flavours of ADD2 cards: ADD2-N (normal) and ADD2-R (reverse). "Normal cards use the first channels on the PCI-E connector while Reverse cards use the last channels." The ADD2-N cards are reported to work without fuss under Linux with Intel chipsets ranging from the 915 through to the 965.
A different source claims that ADD2-N are for ATX
form-factor systems while ADD2-R is for BTX
form-factor systems. However, some BTX systems require ADD2-N (e.g. HP dc5700), so you will have to consult your system documentation.
According to Reseller Advocate (RAM magazine) a Media Expansion Card (MEC) is "an x16 PCIe card with an SDVO silicon module for VGA, DVI, S-Video, composite, or component output combined with an x1 PCIe analog TV tuner" introduced as a "945G platform add-on descended from the old ADD and ADD2 cards."
The application note for the 945G describes the SDVO card interface as requiring a full x16 PCI-E slot.
(GMA 900 through 3000 families).
This chipset allows the ADD2/MEC design to support TV-out (composite video
), TMDS
for DVI 1.0, LVDS, single device operating in dual-channel mode, VGA
output, HDTV
output, HDMI
/UDI support (when used with the HD Audio Link).
SDVO makes it possible to use a 16-lane PCI express
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
slot to add additional video signalling interfaces such as VGA
Video Graphics Array
Video Graphics Array refers specifically to the display hardware first introduced with the IBM PS/2 line of computers in 1987, but through its widespread adoption has also come to mean either an analog computer display standard, the 15-pin D-subminiature VGA connector or the 640×480 resolution...
and DVI
Digital Visual Interface
The Digital Visual Interface is a video interface standard covering the transmission of video between a source device and a display device. The DVI standard has achieved widespread acceptance in the PC industry, both in desktop PCs and monitors...
monitor outputs, SDTV
Standard-definition television
Sorete-definition television is a television system that uses a resolution that is not considered to be either enhanced-definition television or high-definition television . The term is usually used in reference to digital television, in particular when broadcasting at the same resolution as...
and HDTV
High-definition television
High-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...
television outputs, or TV tuner inputs to a system board containing an integrated Intel 9xx-series graphics processor.
SDVO adaptor cards are variously designated as ADD2 (advanced digital display, second generation) or the more feature-rich MEC (media expansion card). MEC is sometimes designated as ADD2+ in Intel documents.
Intel often refers to SDVO as Serial DVO to distinguish it from other forms of digital video out associated with prior product generations, such as the AGP
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...
implementation of DVO and older AGP-style ADD expansion cards which are not SDVO compatible.
Proprietary status
Intel's non-standard extension of the PCI express interface is subject to a patent application Mapping SDVO functions from PCI express interface (United States Application 20050172037) filed on 12 December 2003.According to the Intel patent application, the PCI Express standard lacks a "mechanism to make use of a digital display codec using the PCI Express connector." This limitation is attributed to PCI Express defining only a fixed-frequency interface with significant packet encoding overheads, whereas "digital displays need to have variable clocking and transfer rates and need very little overhead for the transfer of video data".
The patent relates a "presence detect" mechanism to detect SDVO-type expansion cards and enable a pin-remapping of the PCI Express socket to convey SDVO signals.
As of January 2007, Intel has not publicly documented an intent to promote SDVO as an industry standard, despite its potential applicability to any PCI express platform with an Integrated Graphics Processor (IGP), or the desirability from the consumer perspective that SDVO adaptor cards be compatible and freely interchangeable among all such systems.
Instead, Intel is actively promoting the development of SDVO drivers across the broad range of operating systems which run on the Intel 9xx platform. In particular, Intel has established the website intellinuxgraphics.org to promote a fully open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
d drivers supporting all video technologies embodied in their 9xx-series platform.
The upshot is that SDVO cards are compatible with a narrow range of Intel-only hardware platforms, but a broad range of software environments within that platform.
Applications
SDVO encoders can be integrated into the motherboard or placed on a PCI expressPCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
card, allowing video connectors to be added or exchanged at low cost. SDVO adaptor cards can be designed for the following purposes (from Intel ADD2 quoted verbatim):
ADD and MEC form factors
SDVO adaptor cards are designated as ADD (advanced digital display) or MEC (media expansion card) or the equivalent ADD2+.Older ADD cards were AGP
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...
-based and did not provide a standard interface, posing difficulties for driver development. The second generation ADD2 cards are PCI express and employ a standard interface. There are, however, two distinct flavours of ADD2 cards: ADD2-N (normal) and ADD2-R (reverse). "Normal cards use the first channels on the PCI-E connector while Reverse cards use the last channels." The ADD2-N cards are reported to work without fuss under Linux with Intel chipsets ranging from the 915 through to the 965.
A different source claims that ADD2-N are for ATX
ATX
ATX is a motherboard form factor specification developed by Intel in 1995 to improve on previous de facto standards like the AT form factor. It was the first big change in computer case, motherboard, and power supply design in many years, improving standardization and interchangeability of parts...
form-factor systems while ADD2-R is for BTX
BTX (form factor)
BTX is a form factor for motherboards, originally intended to be the replacement for the aging ATX motherboard form factor in late 2004 and early 2005...
form-factor systems. However, some BTX systems require ADD2-N (e.g. HP dc5700), so you will have to consult your system documentation.
According to Reseller Advocate (RAM magazine) a Media Expansion Card (MEC) is "an x16 PCIe card with an SDVO silicon module for VGA, DVI, S-Video, composite, or component output combined with an x1 PCIe analog TV tuner" introduced as a "945G platform add-on descended from the old ADD and ADD2 cards."
The application note for the 945G describes the SDVO card interface as requiring a full x16 PCI-E slot.
Intel chipsets supporting SDVO
Intel documents SDVO as existing within the chipsets integrating an Intel Graphics Media AcceleratorIntel GMA
The Intel Graphics Media Accelerator, or GMA, is a series of Intel integrated graphics processors built into various motherboard chipsets....
(GMA 900 through 3000 families).
GMA X3000
The Intel G965 series chipsets implement the GMA X3000 graphics controller, the consumer engine of the Intel Graphics Media Accelerator 3000 family. From the Intel Desktop board DG965RY Technical Product Specification, section 1.5.1.4 "Advanced Digital Display (ADD2/ADD2+) Card Support":This chipset allows the ADD2/MEC design to support TV-out (composite video
Composite video
Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...
), TMDS
Transition Minimized Differential Signaling
Transition-minimized differential signaling is a technology for transmitting high-speed serial data and is used by the DVI and HDMI video interfaces, as well as other digital communication interfaces....
for DVI 1.0, LVDS, single device operating in dual-channel mode, VGA
Video Graphics Array
Video Graphics Array refers specifically to the display hardware first introduced with the IBM PS/2 line of computers in 1987, but through its widespread adoption has also come to mean either an analog computer display standard, the 15-pin D-subminiature VGA connector or the 640×480 resolution...
output, HDTV
High-definition television
High-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...
output, HDMI
High-Definition Multimedia Interface
HDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
/UDI support (when used with the HD Audio Link).
External links
- Intel application note that accompanied the Intel 945G chipset introduction
- Silicon Image offers an SiI1364 / SiI1362 chipset aimed at board designers who wish to implement SDVO products
- Chrontel also provides some chip level SDVO solutions
- Conexant provides chip level solutions for video encoding
- IEI http://www.ieiworld.com/en/Product_IPC.asp?model=SDVO-100DVI SDVO interface VGA/DVI graphics card
- x.org ADD2/ SDVO card notes http://www.x.org/wiki/SDVOADD2Cards