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The application will still work, but it would likely work better if the PC’s hardware and hardware drivers was specifically designed to function for wireless projection. How to Cast From Another Windows 10 PC. To connect from another PC running Windows 10, head to Settings Display on that PC and select “Connect to a wireless display”. Recent Drivers RF HD3035 DRIVER ViewCast Osprey E Pci-e Analog Video / Audio Capture Card Full Profile Hd eBay Cannot Play Back Recorded Audio Default Output Size Out Of Stock Condition: Devices And Global Controls Reviews 0 Write a review srtxsbufbqftetvdeecyx. ViewCast Osprey 260e/460e Linux Drivers. Posted on May 31, 2012 by Steven Toth. ViewCast Osprey 260e/460e Linux drivers – Released Today!

Note

This document describes how drivers can implement a custom Miracast stack in Windows 8.1. As of Windows 10, the OS ships with a built-in Miracast stack that can work on any GPU and it is no longer recommended that drivers implement a custom Miracast stack. This documentation is therefore deprecated and Microsoft may remove support for custom Miracast stacks in a future version of Windows.

Wireless (Miracast) displays can optionally be supported by Windows Display Driver Model (WDDM) 1.3 and later drivers. This capability is new starting with Windows 8.1.

For more information on the requirements of drivers and hardware to support Miracast displays, refer to the Building best-in-class Wireless Projection solutions with Windows 10 guide and the relevant WHCK documentation at Device.Graphics.WDDM13.DisplayRender.WirelessDisplay.

Miracast design guide

These design guide sections describe how display miniport drivers and Miracast user-mode drivers support Miracast displays:

Miracast reference

These reference sections describe how to implement this capability in your drivers:

User-mode device driver interfaces (DDIs)

Wireless display callback functions called by Miracast user-mode drivers

The reference pages in this section describe wireless display (Miracast) user-mode functions that the operating system implements. Only Miracast user-mode drivers can call these functions.

Pointers to the Miracast display callback functions are returned in a MIRACAST_CALLBACKS structure.

TopicDescription
PFN_GET_NEXT_CHUNK_DATAProvides info about the next Miracast encode chunk that was reported to the Microsoft DirectX graphics kernel subsystem when the DXGK_INTERRUPT_TYPE interrupt type is DXGK_INTERRUPT_MIRACAST_CHUNK_PROCESSING_COMPLETE.
PFN_MIRACAST_IO_CONTROLCalled by the user-mode display driver to send the kernel-mode display miniport driver a synchronous I/O control request.
PFN_REGISTER_DATARATE_NOTIFICATIONSCalled by the user-mode driver to register with the operating system to receive network quality of service (QoS) notifications and the current network bandwidth of the Miracast connection.
PFN_REPORT_SESSION_STATUSCalled by the user-mode display driver to report the status of the current Miracast connected session.
PFN_REPORT_STATISTICCalled by the user-mode display driver to report the statistics of the Miracast link to the operating system.

Wireless display functions implemented by Miracast user-mode drivers

The reference pages in this section describe wireless display (Miracast) functions that a Miracast user-mode driver must implement. This type of driver runs in a standalone DLL.

In response to an operating system call to the QueryMiracastDriverInterface function, the Miracast user-mode driver must supply pointers to these functions in the MIRACAST_DRIVER_INTERFACE structure, except for pfnDataRateNotify, which is has a pointer declared in RegisterForDataRateNotifications.

TopicDescription
PFN_CREATE_MIRACAST_CONTEXTCalled by the operating system to create a user-mode Miracast context.
PFN_DESTROY_MIRACAST_CONTEXTCalled by the operating system to destroy a user-mode Miracast context.
PFN_HANDLE_KMD_MESSAGECalled by the operating system to handle the asynchronous kernel-mode message that the Miracast user-mode driver receives when the display miniport driver calls the DxgkCbMiracastSendMessage function.
PFN_DATARATE_NOTIFICATIONCalled by the operating system to notify the Miracast user-mode driver that the bit rate of the Miracast network link has changed. This function is registered with the operating system when the RegisterForDataRateNotifications function is called.
QUERY_MIRACAST_DRIVER_INTERFACECalled by the operating system to query the Miracast user-mode driver interface, MIRACAST_DRIVER_INTERFACE.
PFN_START_MIRACAST_SESSIONCalled by the operating system to start a Miracast connected session.
PFN_STOP_MIRACAST_SESSIONCalled by the operating system to start a Miracast connected session that had earlier been started by a call to the StartMiracastSession function.

Wireless display (Miracast) structures and enumerations

All user-mode structures and enumerations that are used with Miracast display device driver interfaces (DDIs).

TopicDescription
MIRACAST_CALLBACKSContains pointers to wireless display (Miracast) runtime callback functions that the Miracast user-mode driver can call.
MIRACAST_CHUNK_DATAContains encode chunk data that is used when a user-mode driver calls the wireless display (Miracast) GetNextChunkData function.
MIRACAST_CHUNK_IDStores info that identifies a wireless display (Miracast) encode chunk.
MIRACAST_CHUNK_INFOContains info about a specified wireless display (Miracast) encode chunk.
MIRACAST_CHUNK_TYPESpecifies the types of wireless display (Miracast) chunk info that is to be processed.
MIRACAST_DATARATE_STATSContains info used in the wireless display (Miracast) pfnDataRateNotify function about the audio/video encoder bit rate and failed or retried Wi-Fi frames.
MIRACAST_DRIVER_INTERFACEContains pointers to wireless display (Miracast) functions that are implemented by the Miracast user-mode driver.
MIRACAST_PROTOCOL_EVENTSpecifies the types of wireless display (Miracast) protocol event that the user-mode display driver should report.
MIRACAST_SESSION_INFOContains info on a wireless display (Miracast) connected session.
MIRACAST_STATISTIC_DATAContains Miracast statistics data that the user-mode display driver reports to the operating system.
MIRACAST_STATISTIC_TYPESpecifies types of Miracast statistics data that the user-mode display driver generates.
MIRACAST_STATUSSpecifies status types that the user-mode display driver uses to report Miracast connection status.
MIRACAST_WFD_CONNECTION_STATSContains bit rate info on the Wi-Fi Direct connection.

These additional user-mode structures and enumerations support Miracast displays and are new or updated for Windows 8.1:

  • DISPLAYCONFIG_TARGET_BASE_TYPE (new)
  • DISPLAYCONFIG_VIDEO_SIGNAL_INFO (AdditionalSignalInfo child structure added)
  • DISPLAYCONFIG_DEVICE_INFO_TYPE (DISPLAYCONFIG_DEVICE_INFO_GET_TARGET_BASE_TYPE constant added)
  • D3DKMDT_VIDEO_SIGNAL_INFO (AdditionalSignalInfo child structure added)
  • DISPLAYCONFIG_DEVICE_INFO_TYPE (DISPLAYCONFIG_DEVICE_INFO_GET_TARGET_BASE_TYPE constant added)

Kernel-mode DDIs

Wireless display (Miracast) display callback interface

The Miracast display callback interface contains functions that are implemented by the Microsoft DirectX graphics kernel subsystem to support wireless (Miracast) displays. This interface is supported starting in Windows 8.1.

This section contains reference pages for these kernel-mode functions, which are called by Windows Display Driver Model (WDDM) 1.3 and later display miniport drivers:

TopicDescription
DXGKCB_MIRACAST_SEND_MESSAGESends an asynchronous message to the user-mode display driver.
DXGKCB_MIRACAST_SEND_MESSAGE_CALLBACKCalled in kernel mode when the message that was sent to the user-mode driver with a call to the DxgkCbMiracastSendMessage function has completed or has been canceled.
DXGKCB_MIRACAST_REPORT_CHUNK_INFOCalled by the display miniport driver to report info about an encode chunk.

The display miniport driver must fill in pointers to these functions in the DXGK_MIRACAST_DISPLAY_CALLBACKS structure.

Wireless display (Miracast) interface

This section contains kernel-mode functions that are implemented by display miniport drivers that support wireless (Miracast) displays. This interface is supported starting in Windows 8.1.

Drivers Viewcast

Pointers to the Miracast interface functions are returned in a DXGK_MIRACAST_INTERFACE structure.

TopicDescription
DXGKCB_MIRACAST_SEND_MESSAGE_CALLBACKCalled in kernel mode when the message that was sent to the user-mode driver with a call to the DxgkCbMiracastSendMessage function has completed or has been canceled.
DXGKDDI_MIRACAST_CREATE_CONTEXTCreates a kernel-mode context for a Miracast device.
DXGKDDI_MIRACAST_DESTROY_CONTEXTDestroys an instance of a Miracast device.
DXGKDDI_MIRACAST_HANDLE_IO_CONTROLCalled by the operating system to request that the display miniport driver process a synchronous I/O control request in response to a user-mode display driver call to the MiracastIoControl function.
DXGKDDI_MIRACAST_QUERY_CAPSQueries the Miracast capabilities of the current display adapter. The operating system calls this function only when the display adapter is first started and then stores the capabilities that are returned.

These additional kernel-mode structures and enumerations support Miracast displays and are new or updated for Windows 8.1:

  • D3DKMDT_VIDEO_OUTPUT_TECHNOLOGY (D3DKMDT_VOT_MIRACAST constant added)
  • D3DKMDT_VIDEO_SIGNAL_INFO (AdditionalSignalInfo child structure added)
  • DXGK_CHILD_STATUS (Miracast child structure added)
  • DXGK_CHILD_STATUS_TYPE (StatusMiracast constant added)
  • DXGKARGCB_NOTIFY_INTERRUPT_DATA (MiracastEncodeChunkCompleted child structure added)

Originally Published: May 29th, 2012

Inthis continuing series on defining Legitimately High Fidelity Loudspeakers, wehave discussed the following topics:

Thisarticle is dedicated to the actual loudspeaker drivers themselves (ie. woofers,tweeters, midranges, etc). Let us firstdefine what a loudspeaker driver is and what its primary role is. A loudspeaker driver is an electromechanicaldevice that converts electrical waves (music is more than impulses) intomechanical vibrations which in turn produces audible soundwaves. The size of the diaphragm will determine thebandwidth in which the loudspeaker will be most efficient at reproducingsound. A bass driver (usually 8” orlarger) is designed to reproduce low frequencies (20-500Hz), a midrange driver(usually 3” to 7”) is designed to reproduce frequencies above 100Hz to 4kHz anda tweeter (typically 1” or smaller) is designed to be most efficient atreproducing high frequencies (ie. 1kHz to 20kHz).


Do Exotic Driver Materials Make Speakers Sound Better YouTube Videos Discussion?

The Basics in Loudspeaker Driver Mechanics

It’simportant to understand how a basic loudspeaker works so we’ve included a basicdiagram of a typical woofer with all the major components labeled.

LoudspeakerDiagram – Courtesy of Polk Audio

The loudspeaker isbroken into several parts:

  • TheDiaphragm (aka cone or dome) - the actual physical surface area of the driverthat moves up and down from the voice coil interaction with the permanentmagnet, thus producing sound by compressing and rarefying air, thus creatingsound waves. (sound is not “moving air”it is propagating pressure fluctuations.)
  • TheDustcap (optional) – located at the center of the cone and covers the voicecoil and can increase rigidity of the diaphragm and most importantly in sealsthe diaphragm.
  • TheBasket (aka. Frame)– the physical structure that holds the entire drivertogether
  • TheVoice Coil – basically a wire coiled around a bobbin (electromagnet) atthe center of the speaker and attached to the spider. When current flows through the coil supplied by the amplifier. it produces a temporarymagnetic field when a signal is applied to interact with the permanent magnet(++ oppose ; +- attract). Whereextra bobbin strength is needed, a collar can be added to that portion of thebobbin not covered by the coil.
  • TheSpider (aka. Damper) – Two prime functions of the spider, in conjunction withthe surround, are to center the diaphragm, and force the forward and back movements of the voice coil tobe linear, so that the coil does not scrape the narrow magnetic gap. The Spider provides the primary restorative force in the suspension beingideally placed close to the motive force, the voice coil. Linearity of a drivers suspension (and hence compliance) iscritical and a lot of research has gone into designing spiders with thenecessary stiffness and linearity, and designed not to add structuralresonances of their own. The compliance of thespider & surround helps determine the low frequency limit of the driversuseful bandwidth, specified by the well-known free-air resonance (fs) parameter
  • TheSuspension (aka. Surround) – typically made of cloth, butyl rubber or foam,attaches the diaphragm to the driver basket and in conjunction with the Spider,helps to control and dampen cone movement. In some cases there may be more than one spider and in some cases(tweeters) there is no spider. Inwoofers, the surround is necessary to simply hold the edge of the cone in placeand, along with the spider, to ensure linear in and out movement of the voicecoil. It also functions as a mechanical termination for the radial travelingwaves in the cone (cones do flex!) where it can dampen standing waves that willoccur. The stiffness of the cone material is a factor in determining thefrequencies at which resonances occur - higher being better, but at leastoutside the intended operating frequency range.
  • ThePermanent Magnet – a fixed DC magnet which is part of the motor structureaffixed to the basket of the driver creating a stable magnetic flux across theannular gap which the voice coil sits in.
  • The Phase Plug (optional) – similar to the cone buttypically looks like a bullet. Itspurpose is three-fold, to reduce moving mass and on-axis beaming and also serve as a heatsink and to a smaller extent offering venting.
  • The Vented Pole Piece (optional) - this is a hole located in the center at the back of thepermanent magnet to help reduce air pressure under the dust cap and cool the voice coil.

To generalize a bit more, the magnet assembly of a loudspeaker consisting of a top plate, bottom plate and pole piece, voice coil and magnet can be considered the 'motor structure'.

ThisPolk example appears to be quite a heavy duty driver as evident by how muchventing and free air-flow they are incorporating into the design. This is the type of bass or midrange driveryou typically see in more expensive speaker systems that are able to sustainhigh output levels with low distortion and low compression. More budget-oriented designs typically won’thave vented pole pieces, which will limit how much thermal energy they are ableto dissipate at high output levels, thus potentially causing morecompression.

Check out our recently added YouTube Video discussion on Loudspeaker Driver Science with Shane Rich, Technical Director of RBH Sound to supplement this article.

YouTube Video Discussion: Loudspeaker Science: Identifying Good Speaker Design

Castvs Steel Stamped Driver Baskets

Loudspeaker driver baskets are typically constructedeither of stamped steel, plastic or cast aluminum. Plastic baskets are generally used solely for cost savings over cast, orheavy gauge stamped frames. They are fine for smaller driver applications (6” or less) but are usually notused for larger and heavier bass drivers where greater durability and rigidityis needed. Though there areexceptions. A well designed moldedplastic basket with glass fiber can provide better acoustics than both stampedand cast aluminum. The plastic can be designed by geometry and with fiber fillto have adequate rigidity, and it offers the benefit of damping any residualparasitic vibrations. Since stamped andcast baskets are more commonplace in the industry, we will focus most of thecomparisons on these two type of frame options.

the only reason to use stamped baskets is for cost savings

Here are the facts about cast aluminum vs. stamped steel frame speakers. Aluminum is paramagnetic. That means it is not entirely NON magnetic,as its permeability (let’s call it ‘desire to carry magnetic lines of force’)is about 5% higher than air. Steel onthe other hand, is hundreds of times more willing than air to carry magneticlines of force, the same way copper carries electrical currents, withease. The result is that the veryattachment of the steel to the top plate (part of the magnetic circuit intowhich the voice coil is immersed) guarantees the amount of magnetic force inthe gap will be reduced by the parasitic flow of magnetic lines of force intothe steel frame. However, much of thiscan be alleviated by moving the basket away from the frontplate by using aplastic, paper or other non-magnetic spacer. Good driver designers know and do this when dealing with stamped frames. In reality, flux leakage though the baskettypically isn’t a huge deal unless you are designing pro drivers that needevery bit of efficiency possible. But weincluded this point in this article to be as thorough as possible whencomparing various basket types.

Still,I can imagine some of you asking, why not use stainless steel instead ofregular steel? Good question. Two reasons: 1. It is much harder to form itby pressing (stamping) and 2. It is much more expensive than soft steel.

Stampedwoofer basket (left pic); Cast basket woofer (right pic)

Asignificant advantage of aluminum over steel is the way in which it effectivelydraws off heat from those parts of the driver that surrounds the voicecoil that get heated most quickly, such as the top plate. (remember, the top plate is directly attachedto the speaker frame, so this physical coupling will result in the transmissionof heat between the parts.) Since mostcast aluminum frames are several times thicker than the steel ones, and sincealuminum is an ideal material for heat sinking (it is what most heat sinks aremade of), it will also let the speaker run cooler for a given amount of current feed into thevoice coil. In addition, it will allow a larger amount of current to be put into the voicecoil by drawing away and dissipating the heat more efficiently than steel cando. The ONLY reason to use steel instead of aluminum for a speaker frame (andit’s a legitimate reason) is cost. Withthe proper tool, a single punch can stake and swage (attach) a steel frame to asteel top plate in a second or less. Nodrilling costly threaded through holes for screws in the top plate isnecessary. There is no need to buy the screws, or make sure they are glued inplace or screwed down with the right amount of torque. Stamped steel is a far less expensive routefor a big mechanized factory than cast frames are.

Castaluminum frames, if properly designed, are always going to offer an advantageover steel frames, especially with respect to rigidity. That being said, you can still have welldesigned stamped steel frames. Thebasket material alone does not define the quality of the driver. Manufacturers building legitimatelywell-engineered stamped frames typically use thicker gauge steel than the onepictured above left. This increasesrigidity and reduces susceptibility to ringing. You will find many of the high output budget subwoofers offered in the$1k or less price range employ thick stamped steel baskets. When trying to hit a target price point,while still offering respectable output and performance, this is a designcompromise that often makes sense.

Editorial Note about Cast Aluminum vs Steel Frames by David Waratuke

Drivers Viewer

The issue of stiffness in a driver basket frame is not one of steel versus aluminum per se, it is one of geometry and manufacturing. Steel as a material is actually three times stiffer than aluminum as indicated by a property call the Modulus of Elasticity, which for steel is around 29,000,000 pounds per square inch (psi) while aluminum is only about 10,000,000 psi; a modular ratio of 2.9. The lower stiffness in a steel basket comes from using stamped manufacturing that limits thickness of resulting basket as compared to what can be cast. This difference in thickness creates an exponential differences in the geometric component of the stiffness for the resulting baskets. It all comes down to the fact that a cast aluminum basket typically contains more aluminum, with the correspondingly increased thickness, than there is steel present in a typical stamped basket and that more than makes up for the aluminum being a softer material.

AdditionalInformation about Cast Frames

Cast aluminum frames are made by pouringmolten aluminum into a block of steel that has been hollowed out using a veryprecise computer-cutting (CNC) program. This process is known as tooling, and it is a central process inall consumer products made today. Whenever you see a nicely molded, shapedpiece of plastic or metal, chances are it has been formed by some sort oftooling process. Tooling is very expensive, so much so that smallermanufacturers jokingly refer to the need to “tool” something as a four-letterword.

There are two basic types of tooling:Proprietary tooling and open tooling. Often proprietary tooling is copied, or the logo is simply ground off.

Drivers Viewsonic

Proprietary tooling is tooling that thatparticular manufacturer designs and pays for themselves, and then they own thetooling and retain the rights to it forever. There are many distinctive tweeterfaceplates, woofer frames, or plastic satellite cubes which we associate with aparticular manufacturer’s look and style, and that’s because they’ve done theirown tooling. The manufacturer will often protect their tooling appearance witha design patent, in order to make their design immune to counterfeiting andunauthorized copying.

Drivers

Good examples of proprietary, patentedtooling are Boston Acoustics’ automotive Pro Series cast aluminum wooferbaskets and Bose’s famous satellite cubes.

BostonAcoustics Pro Series Woofer (left pic) ; Bose mid woofer (right pic)

The other kind of tooling is what’s known as“open tooling.” Open tooling is tooling that a vendor of raw parts undertakesthemselves in anticipation that many of its customers will order their parts,thus making their (the vendor’s) speculative investment in the toolingworthwhile in the long run. Examples of open tooling are the cast wooferbaskets that many driver vendors make for their line of general distributionwoofers, for example, or the round plastic frames for ceiling speakers offeredby many Far East vendors to “brand name” speaker companies. You can lookclosely at the metal woofer baskets or round plastic ceiling mounting framesfrom many speaker companies and find that they are identical, absolutelyidentical.

There is nothing wrong with that, of course.The frame, top plate, back plate, and magnet are known as the speaker’s “hardparts.” It’s expensive for small speaker companies to tool and manufacturethose, so they buy them pretty much “off the shelf.” The “soft parts” of aspeaker—the cone, surround, voice coil, spider—are easier to customize andchange from run to run, so that’s where a lot of differentiation comes in forthe speaker companies. Brand A and Brand B may use the same basket, top plateand back plate, all tooled by Vendor C, but they specify and customizedifferent soft parts, and the resulting woofers are completely different, eachaccording to that particular company’s engineering design goals and marketingobjectives. Again even unique customtooled motor designs do not remain proprietary. They are copied. That'sprogress.

Cast baskets are more rigid than stamped alternatives

Rigidityof Cast vs Stamped Baskets

Regarding resistance to shipping damage, thisis a real concern. In the early 1990’s when magnetic shielding was importantfor speakers in a home theater so as not to interfere with CRT televisions,many speaker manufacturers added “bucking magnets” onto their speakers’ existingmagnet structures. This was another magnet, reversed, so its external magneticfield would cancel out, and then the entire structure was typically enclosed ina shielding “can” to further reduce stray leakage.

The problem was that now these speakers’frames were being asked to carry significant added weight for which theyweren’t designed. One major company was using a plastic frame and the additional weight of the bucking magnet andshielding were causing these frames to crack and break off during shipping.Another company was using stamped steel frames on their midranges, but thestruts were not reinforced with crimped sections—they were flat and thus veryprone to bending because of the added weight. The entire first shipment ofthese new speakers went out to the dealers and the mids were all inoperative,because the weight of the magnetically-shielded structures had torqued theframes so badly in shipping that the voice coils were all frozen out ofalignment. Both of these companies redesigned their baskets with additionalreinforcing ribs and added internal cabinet supports around the drivers to keepthem from moving and being damaged in shipping. So there is no question thatthe added rigidity and precise alignment afforded by cast frames is theirbiggest advantage. Cast baskets tend to hold the parts inalignment more accurately and with greater longevity. It has been proven countless times that suchbaskets survive shipping drops better than stamped baskets.

Bottom Line on DriverBaskets

Stampedbaskets are less costly to produce than cast baskets and are at a disadvantagein some aspects (strength, cooling, etc), but respectably good performance canstill be achieved with stamped frames. You will typically find the very best loudspeaker designs on the marketwill take advantage of the properties of cast baskets and thus employ them inALL of their drivers. Plus—cast-basketdrivers look so darned cool when they’re photographed by themselves! Anyspeaker marketing department worth its salt knows that!