Windows Media Center TV Pack 2008 RTM is Build 6.1.1000.18273, designed for implementation on top of Windows Media Center in Windows Vista RTM or Windows Vista Service Pack 1. The gold bits have been available since July 16, according to the Redmond company. But even so, Microsoft will only offer the first details on Windows Media Center TV Pack 2008 on September 3.

What questions do you have about the Windows Media Center TV? I can’t answer or comment on any of them until the official announcements happen at CEDIA. But I can think about the answers before then. If you have specific questions about the Windows Media Center TV Pack leave them

What’s the neatest feature in Microsoft’s Windows Vista operating system?
The answer is simple: Windows Media Center. And the good news is that the media-centric interface just got its biggest overhaul since Vista launched. The Windows Media Center TV Pack 2008 software lets PCs receive high-definition cable content without requiring specially certified systems (though CableCARDs are required for premium, encrypted content). That means high-def cable for the rest of us!

The Windows Media Center TV Pack was released on July 16, 2008. Not all computers that are shipped by hardware vendors in the retail channel have the Windows Media Center TV Pack installed. To check whether your computer has the Windows Media Center TV Pack installed, follow these steps:

1. Start Windows Media Center.
2. In the Start window, scroll to Tasks, click Settings, and then click General.
3. Click About Windows Media Center, and then click Software Version.

If the version is 6.1.1000.18273, you are running the Windows Media Center TV Pack.

If the version number is 6.0.6001.18000, you are not running the Windows Media Center TV Pack. You are running the version of Windows Media Center that is included in Windows Vista or in Windows Vista SP1.

Fiji, officially known as Windows Media Center TV Pack 2008, has Released! The input from Self Host testers has been invaluable to this product and the team would like to thank each of you for your bug reports and feedback. As the release team is taking a much needed break, our next focus will be to post the final build onto the Products servers. Please check the newsgroups for updates. Once the build is live, we will notify you.

ATSC – HD TV Standard

ATSC is a set of standards developed by the Advanced Television Systems Committee for digital television transmission that replaced much of the analog NTSC television system on June 12, 2009 in the United States .

The ATSC standard was developed in the early 1990s by the Grand Alliance, a consortium of electronics and telecommunications companies that assembled to develop a specification for what is now known as HDTV. ATSC Standard A/53, which implemented the system developed by the Grand Alliance, was published in 1995; the standard was adopted by the Federal Communications Commission in the United States in 1996.

The high definition television standards defined by the ATSC produce wide screen 16:9 images up to 1920×1080 pixels in size — more than six times the display resolution of the earlier standard. However, many different image sizes are also supported, so that up to six standard-definition “subchannels” can be broadcast on a single 6 MHz TV channel.

ATSC also boasts 5.1-channel surround sound using the Dolby Digital AC-3 format. Numerous auxiliary datacasting services can also be provided.

Resolution

The ATSC system supports a number of different display resolutions, aspect ratios, and frame rates. The formats are listed here by resolution, form of scanning (progressive or interlaced), and number of frames (or fields) per second (see also the TV resolution overview at the end of this article). The table includes formats from both A/53 Part 4 (MPEG-2 Video System Characteristics) and A/63 (Standard for Coding 25/50 Hz Video).

The different resolutions can operate in progressive scan or interlaced mode, although the highest 1080-line system cannot display progressive images at the rate of 59.94 or 60 frames per second. (Such technology was seen as too advanced at the time, plus the image quality was deemed to be too poor considering the amount of data that can be transmitted.) A terrestrial (over-the-air) transmission carries 19.39 megabits of data per second, compared to a maximum possible bitrate of 10.08 Mbit/s allowed in the DVD standard and 48 Mbit/s allowed in the Blu-ray disc standard.

There are three basic display sizes for ATSC. Basic and enhanced NTSC and PAL image sizes are at the bottom level at 480 or 576 lines. Medium-sized images have 720 scanlines and are 1280 pixels wide. The top tier has 1080 lines 1920 pixels wide. 1080-line video is actually encoded with 1920×1088 pixel frames, but the last eight lines are discarded prior to display. This is due to a restriction of the MPEG-2 video format, which requires the number of coded luma samples (i.e. pixels) to be divisible by 16.

Codecs

For transport, ATSC uses the MPEG-2 systems specification, known as transport stream, to encapsulate data, subject to certain constraints. ATSC uses 188-byte MPEG transport stream packets to carry data. Before decoding of audio and video takes place, the receiver must demodulate and apply error correction to the signal. Then, the transport stream may be demultiplexed into its constituent streams.

Since July 2008, ATSC supports the ITU-T H.264 video codec. The standard is split in two parts:

• A/72 part 1: Video System Characteristics of AVC in the ATSC Digital Television System
• A/72 part 2 : AVC Video Transport Subsystem Characteristics

The earlier specification also supports MPEG-2 video as the video codec, with certain constraints.

Digital television

Digital television (DTV) is the sending and receiving of moving images and sound by discrete (digital) signals, in contrast to the analog signals used by analog TV.

Formats and bandwidth

Digital television supports many different picture formats defined by the combination of size, aspect ratio (height to width ratio) and interlacing. With terrestrial broadcasting in the USA, the range of formats can be coarsely divided into two categories: HDTV and SDTV. It should be noted that these terms by themselves are not very precise, and many subtle intermediate cases exist.

High-definition television (HDTV), one of several different formats that can be transmitted over DTV, uses one of two formats: 1280 × 720 pixels in progressive scan mode (abbreviated 720p) or 1920 × 1080 pixels in interlace mode (1080i). Each of these utilizes a 16:9 aspect ratio. (Some televisions are capable of receiving an HD resolution of 1920 × 1080 at a 60 Hz progressive scan frame rate — known as 1080p60, but this standard is not currently used for transmission.) HDTV cannot be transmitted over current analog channels.

Standard definition TV (SDTV), by comparison, may use one of several different formats taking the form of various aspect ratios depending on the technology used in the country of broadcast. For 4:3 aspect-ratio broadcasts, the 640 × 480 format is used in NTSC countries, while 720 × 576 (rescaled to 768 × 576) is used in PAL countries. For 16:9 broadcasts, the 704 × 480 (rescaled to 848 × 480) format is used in NTSC countries, while 720 × 576 (rescaled to 1024 × 576) is used in PAL countries. However, broadcasters may choose to reduce these resolutions to save bandwidth (e.g., many DVB-T channels in the United Kingdom use a horizontal resolution of 544 or 704 pixels per line). This is done through the use of interlacing, in which the effective vertical resolution is halved to 288 lines.

Limitations

The greatest DTV detail level currently available is 1080i, which is a 1920 × 1080 interlaced widescreen format. Interlacing is done to reduce the image bandwidth to one-half of full-frame quality, which gives better frame update speed for quick-changing scenes such as sports, but at the same time reduces the overall image quality and introduces image flickering and “crawling scanlines” because of the alternating field refresh.

Full-frame progressive-scan 1920 × 1080 (1080p) is part of the ATSC specification, but is rarely if ever used by broadcasters due to the increased bandwidth requirements compared to transmitting 720p/1080i video. High frame-rate 1080p may become an option in the near future, as a result of recent technology advances such as H.264/MPEG-4 AVC video coding, allowing more detail to be sent via the same channel bandwidth allocations that are used now.

The limitations of interlacing can be partially overcome through the use of advanced image processors in the consumer display device, such as the use of Faroudja DCDi and using internal frame buffers to eliminate scanline crawling.

In practice DTV is transmitted non-interlaced as can be demonstrated by the 16×16 pixellated blocks occurring in weak signal areas. If the transmission was interlaced, only the odd or even frames would be corrupted. In order to reduce bandwidth DTV transmits difference information frame to frame, with occasional full frame transmissions. The receiving decoder converts the buffered frames to suit the display device. Typically these will be interlaced but could be non-interlaced such as LCDs. Similarly at the transmitter the interlaced or non interlaced source material will be reformatted and buffered before the non-interlaced difference information is transmitted. Although a method of transmitting interlaced difference data was discussed it was believed too complicated for both transmitter and receiver.

Altogether the number of up and down scalings, convertings and deconvertings means that a well received analogue picture (no ghosting) may be more complete and pleasing to watch than digital. This difference in over all image quality shows up particularly when watching sporting events. As the camera tracks with the subject and the background moves, the result is a time delay in processing. The digital rendering can become increasingly pixellated. The degree of pixellation depends highly on the type of television in use (LCD vs. DLP vs. Plasma vs. LED) and the speed and ability of the television to process images (30 Hz, 60 Hz, 120Hz, 240 Hz).

High-definition television (or HDTV) is a digital television broadcasting system with higher resolution than traditional television systems (standard-definition TV, or SDTV). HDTV is digitally broadcast; the earliest implementations used analog broadcasting, but today digital television (DTV) signals are used, requiring less bandwidth due to digital video compression.

High-definition display resolutions

Standard frame or field rates

• 23.976 Hz (film-looking frame rate compatible with NTSC clock speed standards)
• 24 Hz (international film and ATSC high definition material)
• 25 Hz (PAL, SECAM film, standard definition, and high definition material)
• 29.97 Hz (NTSC standard definition material)
• 50 Hz (PAL & SECAM high definition material))
• 60 Hz (ATSC high definition material)

At a minimum, HDTV has twice the linear resolution of standard-definition television (SDTV), thus showing greater detail than either analog television or regular DVD. The technical standards for broadcasting HDTV also handle the 16:9 aspect ratio images without using letterboxing or anamorphic stretching, thus increasing the effective image resolution.

The optimum format for a broadcast depends upon the type of videographic recording medium used and the image’s characteristics. The field and frame rate should match the source and the resolution. A very high resolution source may require more bandwidth than available in order to be transmitted without loss of fidelity. The lossy compression that is used in all digital HDTV storage and transmission systems will distort the received picture, when compared to the uncompressed source.

Recording and compression

HDTV can be recorded to D-VHS (Digital-VHS or Data-VHS), W-VHS (analog only), to an HDTV-capable digital video recorder (for example DirecTV’s high-definition Digital video recorder, Sky HD’s set-top box, Dish Network’s VIP 622 or VIP 722 high-definition Digital video recorder receivers, or TiVo’s Series 3 or HD recorders), or an HDTV-ready HTPC. Some cable boxes are capable of receiving or recording two or more broadcasts at a time in HDTV format, and HDTV programming, some free, some for a fee, can be played back with the cable company’s on-demand feature.

The massive amount of data storage required to archive uncompressed streams meant that inexpensive uncompressed storage options were not available in the consumer market until recently. In 2008 the Hauppauge 1212 Personal Video Recorder was introduced. This device accepts HD content through component video inputs and stores the content in an uncompressed MPEG transport stream (.ts) file or Blu-ray format .m2ts file on the hard drive or DVD burner of a computer connected to the PVR through a USB 2.0 interface.

Realtime MPEG-2 compression of an uncompressed digital HDTV signal is prohibitively expensive for the consumer market at this time, but should become inexpensive within several years (although this is more relevant for consumer HD camcorders than recording HDTV). Analog tape recorders with bandwidth capable of recording analog HD signals such as W-VHS recorders are no longer produced for the consumer market and are both expensive and scarce in the secondary market.

In the United States, as part of the FCC’s plug and play agreement, cable companies are required to provide customers who rent HD set-top boxes with a set-top box with "functional" Firewire (IEEE 1394) upon request. None of the direct broadcast satellite providers have offered this feature on any of their supported boxes, but some cable TV companies have. As of July 2004, boxes are not included in the FCC mandate. This content is protected by encryption known as 5C. This encryption can prevent duplication of content or simply limit the number of copies permitted, thus effectively denying most if not all fair use of the content.

Table of terrestrial HDTV transmission systems

Main characteristics of three HDTV systems

Systems	ATSC	DVB-T	ISDB-T
Source coding
Video	Main Profile syntax of ISO/IEC 13818-2 (MPEG-2 – Video)
Audio	ATSC Standard A/52 (Dolby AC-3)	As defined in ETSI DVB TS 101 154 – as H.264 AVC and/or ISO/IEC 13818-3 (MPEG-2 – Layer II Audio) and/or Dolby AC-3	ISO/IEC 13818-7 (MPEG-2 – AAC Audio)
Transmission system
Channel coding
Outer coding	R-S (207, 187, t = 10)	R-S (204, 188, t =
Outer interleaver	52 R-S block	convolutional (I=12, M=17, J=1)	12 R-S block
Inner coding	rate 2/3 Trellis code	Punctured convolution code(PCC): rate 1/2, 2/3, 3/4, 5/6, 7/8; constraint length = 7, Polynomials (octal) = 171, 133
Inner interleaver	12 to 1 Trellis code	bit-wise, frequency, selectable time
Data randomization	16-bit PRBS
Modulation	8VSB (Only used for over the air transmission) 16VSB (Designed for cable, but rejected by the cable industry, cable TV uses 64QAM or 256QAM modulation as a de facto standard)	COFDM QPSK, 16QAM and 64QAM Hierarchical modulation: multi-resolution constellation (16QAM and 64QAM) Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol Two modes: 2k and 8k FFT	BST-COFDM with 13 frequency segments DQPSK, QPSK, 16QAM and 64QAM Hierarchical modulation: choice of three different modulations on each segment Guard interval: 1/32, 1/16, 1/8 & 1/4 of OFDM symbol Three modes: 2k, 4k and 8k FFT