Quality Windows Audio/Video Experience (qWAVE)
Quality Windows Audio/Video Experience (qWAVE) is the next generation Quality of Service (QOS) platform introduced in Windows Vista.
qWAVE provides new features focused on streaming multimedia and real-time content over variable bandwidth networks. These features include the following.
- Auto-discovery of end-to-end QOS compatibility.
- End-to-end bandwidth estimation of maximum link capacity (bottleneck bandwidth) and real-time available bandwidth.
- Intelligent packet prioritization.
- Congestion notification.
- Flow shaping.
- Distributed admission control, including caching to improve performance and minimize latency.
[MS-QLPB]: Quality Windows Audio/Video Experience (qWave): Layer 3 Probing Protocol
Specifies the Quality Windows Audio/Video Experience (qWave): Layer 3 Probing (L3P) (qWave) Protocol, which operates over TCP/IP and UDP/IP. qWave enables applications to evaluate link bandwidth and quality by analyzing timestamps of probe packets transmitted between two devices.
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Quality Windows Audio Video Experience (qWave)
qWave is a collection of QoS-related software modules that run on qWave-enabled devices in non-enterprise environments, such as a home network or small-office network. qWave supports multiple audio/video streams (real-time flows requiring QoS) and data streams (best-effort flows, such as e-mail) simultaneously over the network, while providing a high-quality audio/video (A/V) user experience. The devices cooperate to ensure that data streams (for which the application has requested QoS) receive the level of quality that they were granted upon admission to the network. Because qWave is targeted for home and small-office A/V scenarios, it is typically disabled in other environments, such as enterprise networks.
qWave Overview
QoS refers to the mechanisms that are implemented to provide a desired level of network service to an application on IP-based networks. The network service parameters might include bandwidth, jitter, latency, and packet loss. The desired level of network service can be achieved by explicitly reserving bandwidth on the network for a service, or by providing preferential service to selected network traffic while providing best-effort service to all other traffic.
qWave is a collection of QoS-related software modules—first included on computers running Windows Vista®—in non-enterprise environments, such as a home network or small-office network. qWave supports multiple A/V streams (real-time flows requiring QoS), and data streams (best-effort flows, such as e-mail) simultaneously over the network, while providing a high-quality A/V user experience. The devices cooperate to ensure that data streams for which the application has requested QoS receive the level of quality that they were granted upon admission to the network. Because qWave is targeted for home and small-office A/V scenarios, it is typically disabled in other environments, such as enterprise networks.
Reservation techniques—such as RSVP—are not implemented for home A/V streaming. Bandwidth reservation guarantees are meaningless if the Wi-Fi station moves out of the broadcast range of the wireless access point (wireless AP) or if some obstruction or interference causes a drop in link bandwidth. Additionally, for price-sensitive home networking markets, reservation-based QoS features might make devices cost-prohibitive.
Instead, qWave provides preferential service for traffic prioritization and other throughput, range, and stability-enhancement mechanisms. These mechanisms are available in many wireless APs, wireless network adapters and other devices. These mechanisms include 802.1p support for switches, hubs, and network adapters, as well as Wireless Multimedia Extensions (WME) support in wireless APs.
qWave provides the best experience when both the source and the target devices are qWave-enabled, and when the network devices support traffic prioritization. However, qWave also provides an improved experience without priority support in either the network or legacy devices.
On Windows Server platforms, qWave provides only rate-of-flow and prioritization services.
Quality windows audio video experience что это за служба
Quality Windows Audio Video Experience (qWave) is a networking platform for Audio Video (AV) streaming applications on IP home networks. qWave enhances AV streaming performance and reliability by ensuring network quality-of-service (QoS) for AV applications. It provides mechanisms for admission control, run time monitoring and enforcement, application feedback, and traffic prioritization.
This service also exists in Windows 10, 8 and Vista.
Startup Type
| Windows 7 edition | without SP | SP1 |
|---|---|---|
| Starter | Manual | Manual |
| Home Basic | Manual | Manual |
| Home Premium | Manual | Manual |
| Professional | Manual | Manual |
| Ultimate | Manual | Manual |
| Enterprise | Manual | Manual |
Default Properties
Default Behavior
The Quality Windows Audio Video Experience service runs as NT AUTHORITY\LocalService in a shared process. It shares the executable file with other services. If the Quality Windows Audio Video Experience fails to load or initialize, the error is recorded into the Event Log. Windows 7 startup should proceed, but a message box is displayed informing you that the QWAVE service has failed to start.
Dependencies
Quality Windows Audio Video Experience will not start, if the following services are stopped or disabled:
- Link-Layer Topology Discovery Mapper I/O Driver
- QoS Packet Scheduler
- QWAVE driver
- Remote Procedure Call (RPC)
Restore Default Startup Type of Quality Windows Audio Video Experience
Automated Restore
1. Select your Windows 7 edition and Service Pack, and then click on the Download button below.
2. Save the RestoreQualityWindowsAudioVideoExperienceWindows7.bat file to any folder on your hard drive.
3. Right-click the downloaded batch file and select Run as administrator.
4. Restart the computer to save changes.
Note. Make sure that the qwave.dll file exists in the %windir%\system32 folder. If this file is missing you can try to restore it from your Windows 7 installation media.
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