Optimizing Video Quality for Windows XP

Introduction

Video playback is one of the most innovative and compelling features of Media Center PCs running Microsoft® Windows® XP Media Center Edition. Quality video playback is essential to sales and widespread adoption of Media Center PCs; reviewers and customers tend to perceive the quality of the overall system on the basis of video playback—if video playback is poor, they tend to perceive the quality of the entire Media Center PC as poor.

Video playback on Media Center PCs is complex and depends heavily on the quality of individual components that are involved in the video playback path. These components include the following:

• TV tuner/capture/compressor device.
• MPEG-2 video decompressor.
• Graphics hardware, including graphics acceleration hardware and the display adapter.
• Display monitors, including CRT/LCD/PDP/DLP computer displays and televisions.

This paper describes the role of each component in video playback, the factors that can contribute to poor video quality, and recommends configurations and tests to obtain the best possible video quality. The paper also lists troubleshooting tips that manufacturers can offer customers who purchase Media Center PCs. This paper is intended to help system manufacturers choose components and adjust settings for the best user experience with video on PCs running Windows XP Media Center Edition. The information in this paper can also be used to guide reviewers and users who are trying to optimize video quality on Media Center PCs.

This paper assumes that readers are familiar with television features of the Media Center user interface in Windows XP Media Center Edition. It also assumes that readers are familiar with the system requirements for Media Center PCs.

System requirements are listed in the Design Guide for Windows XP Media Center Edition. For availability of this document and sources of information about video signals and video processing, see the Resources and Tools section at the end of this paper.

TV/Tuner Capture/Compressor Devise

A TV tuner/capture/compressor device combines the separate video processing stages of tuning, digitization, and compression on a single PCI-compatible add-on board, a USB 2.0, or a 1394 hot-pluggable device. These products are often marketed as personal video recorder (PVR) devices for computers. The PVR device brings compressed broadcast television to the Media Center PC.

TV Tuner

The TV tuner receives a radio frequency (RF) signal from an antenna or cable feed. When the user enters a channel number in the Media Center PC, the TV tuner is the hardware that finds the corresponding RF signal.

Signals appearing as base-band composite video, S-video, or line-level audio from a set-top box, VCR, or DVD player bypass the TV tuner component. Thus, the tuner can be removed from the video processing chain to determine its affect on video quality.

How the TV Tuner Affects Video Quality

Problems with tuning can cause video artifacts, such as ghosting, video snow, and rolling bars or distorted colors. A poor tuner can also lead to corrupted vertical blanking interval (VBI) or closed-caption (CC) data and weak or garbled audio. The most common causes of video artifacts result from the following:

• The user attached the coaxial cable to the wrong connector.
• The tuner has poor sensitivity to attenuated signals.
• The RF signal is weak or scrambled on some channels.
• The TV tuner is set to the wrong input format (antenna/cable or NTSC/PAL).

Speed Up The Windows XP Boot Process

According to a report published by Microsoft several years ago, one of the most sought-after features for PC users over the years has been a lightning fast sytem start-up. Perhaps that is just the way we expect all our gadgets to work; punch the correct button and expect an instantaneous response. While the folks over at Redmond have since then taken tangible steps in making this a rality in the beta release of the upcoming Windows 7 operating system for now, their claim of getting boot time down to under 15 seconds is still wishful thinking at best.

In general, modern systems these days take anywhere between 30 seconds to a full minutes before they are able to run a program for the user. As a matter of fact, real world telemetry data at the Engineering Windows 7 blog suggests that an overwhelming majority of computer system (approximately 75 per cent of the total) running Windows Vista SP1 take up to a minute to boot before they are actually usable and ready to carry out tasks. Unsurprisingly, Windows XP based systems fare better in this regard, though only marginally.
Getting Started
Simply put, the main factors that determine boot time are the processes, programs and drivers that load up automatically each time you start your computer. So if you have countless processes and star-up times schedule to run whenever your computer boots, it will take more time for it to start up. Unfortunately, there is no definite way to highlight the exact cause of these slowdowns using the functionality built into Windows XP. However, there are a few sure-fire ways, apart from the hackneyed defragmenting your hard drive routine, that can help you speed up your boot process substantially and thereby cut down the time it takes for the desktop to appear whenever you turn on your computer. This is where BootVis comes in.


BootVis
Originally released by Microsoft (though no longer supported by them) for system designers and software developers to identify boot performance issues, BootVis (download) essentially is a "performance tracing and visualization tool" that can quickly determine how long a machine takes to boot up Windows XP; display all its findings graphically and then optimize the system's boot sequence, thus reducing the start-up time in the process.

A typical BootVis trace presents a complete time line of a computer's start-up sequence on easy to read graphs, displaying useful data, such as when each process starts and finishes during the entire boot up phase. This, for instance, can be used to precisely pinpoint where the slowdowns, if any, are occurring.

However, depending largely on your system configuration, you may or may not see a dramatic reduction in start-up time. To get a good estimate of the difference, record your original start-up time with stopwatch to obtain a reference reading before using BootVis.

Procedure
Assuming you have already downloaded and installed BootVis, the overall optimization procedure is as follows:

1. Once you have run the BootVis executable, the first step involves running a boot trace. From the BootVis window, click 'File', followed by 'New' and 'Next Boot + Drivers Trace'. In the subsequent 'Trace Repetitions' window that appears, accept the default values for the number of repetitions to run. Note that the more times the utility runs, the more accurate the results will be, although the trace will take aneven longer time to complete. Secondly, ensure that the 'Restart automatically after tracing' option is selected before clicking OK. After a ten-second countdown, BootVis will reboot your system to perform the trace.
2. Once the system restarts, wait a few seconds for BootVis to automatically launch and display a series of graphs on boot activity, CPU usage, driver delay, etcetera. You don't specifically need any knowledge of these graphs as the utility will automatically make the appropriate adjustments to your machine late. To proceed with the boot sequence optimization, click 'Trace', followed by 'Optimize System' and BootVis will display another ten-second countdown before rebooting.
3. After rebooting, wait a few seconds for a BootVis prompt to appear, alerting you that it's reorganizing your boot files for faster start-up. Once the alert goes away (it normally takes a couple of minutes), you can use your computer as you would normally. Reboot again and see the difference.
   
4. By default, Windows wait for a certain amount of time to display a list of available operating systems before loading. If you're not multi-booting and wish to remove this delay, right-click 'My Computer' and select 'Properties'. Click the 'Advanced' tab and, under the 'Startup and Recovery' section, click 'Settings'. In the "time to display list of operating systems" box, set the default value to 0 (zero) seconds and restart your computer.
5. One of the most effective ways of reducing boot time is to keep all Windows services in check. Every time you start up, a boatload of components or 'services' get crammed into your PC's memory. However, not all of these are essential to the normal working of your system. To do away with the ones you don't need, use the Services applet in Windows XP. To access it, go to 'Run', type 'services.msc' and press Enter. For a comprehensive list of services that can be safely disabled in Windows XP SP3, visit Black Viper's website mentioned in The Site.
   
6. Next you need to disable any unnecessary programs that automatically start at the beginning of each Windows session. To do so, click 'Run', type 'msconfig' and press Enter. Once the System Configuration Utility opens, click the Startup tab and uncheck the boxes on the left-hand side to keep items from loading. For instance, you can safely disable programs such as MSN or Yahoo Messenger, Real Player, etcetera. You will need to experiment to see what you can do without.
7. Contrary to popular belief, Windows isn't the only culprit that can slow down the boot process. Your computer's hardware, too, can put everything on hold to quite some time. This is where tweaking the BIOS utility can prove to so beneficial. Tap the F1, F2 or Del key while booting (check you documentation) to enter the BIOS and change the bot device priority by setting your hard drive as the first boot device. Additionally, ensure that the Quick Power On Self Test (POST) option is enable and that the hard disk pre-delay is set to disabled. Also, if you don't have a secondary IDE disk drive in place, configure the BIOS to not look for one on the primary and secondary channels. For instance, when set to 'Auto', your PC pauses to identify each IDE device as it boots, thereby wasting a few seconds. Set this to 'None' where applicable.

While BootVis is a powerful tool with several optimization options, it can't work miracles. This is where you need to manually tweak your system by exercising good judgment and some common sense. Not only will these tips help shave a few seconds off your boot time, they will ultimately lead to a better user experience with Microsoft's aging beast.