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HDMI stands for High Definition Multimedia Interface. An HDMI cable is digital interface connector that transmits both video and audio signals. A single HDMI cable can be used to replace all of the cable connections between a high definition television and other high definition devices, such as a Blu-ray or HD DVD player.
Other methods can be used to connect home theater video components, such as component video, S-video and DVI (digital visual interface). These are legacy type connections that may not have the ability to work properly with some of the latest high definition technologies, such as 1080p resolution and Deep Color. Most HDTVs require the use of an HDMI cable to achieve 1080p resolution from Blu-ray or HD DVD players or cable boxes. It is therefore safe to assume that you should use a quality HDMI cable, at least when matching 1080p video components to any 1080p HDTV.
Are all the cables the same?
No. According to the official HDMI site, there are two types of cables. Older standard Speed cables, also called Category 1, support 720p and 1080i resolutions. Standard Speed cables are not rated for 1080p. High Speed cables, also called Category 2, are rated for all HDTV resolutions, including 1080p. A Category 1 cable has been tested for speeds up to 75 MHz, while a Category 2 cable is approved for up to 340 MHz. All version 1.3 cables are Category 2 cables.
Do I need to purchase expensive cables?
No, but you should purchase cables from a quality manufacturer. The price on many Monster cables exceeds $100 per cable, but good quality cables can be found for as little as $20. If you have a 720p or 1080i system with a short cable run, almost any cable should work. If you are working with 1080p HDTV equipment, you might want to invest more than $5 for HDMI cables. I’m using a Philips 6 foot High Speed HDMI Cable that I found at Wal-Mart for $35. The cable is certified for 1.3a and works great.
Whether you are using a $120 Monster cable or a $10 El-Cheapo cable, it is important to keep all audio and video cables away from power cords and cables. AC current can create problems with hum on audio cables and can distort video signals. A good rule of thumb is to always keep audio and video cables and speaker wires at least six inches away from power cords whenever possible–and never bundle audio or video cables together with power cords.
What are all the different versions, such as 1.0, 1.1, 1.2 and 1.3?
The HDMI standard has evolved since it was introduced in 2003. Each new version adds new capabilities. The current standard is 1.3b. The versions are more related to the capabilities that may or may not be required by your home theater components as well as the ability of the cable to deliver those features without loss of quality. All of the versions support 1080p when the cables are certified. The important part to remember is that the HDMI standards refer to the components in a home theater system and not the HDMI cables. The certification on the cable just means that the cable meets the requirements for the standard, but more important is the fact that all HDMI cables that are certified for at least the minimum 1.3 standard will work with 1.3a 1.3b components. In other words, an HDMI 1.3 cable is the same as a 1.3a or 1.3b cable. Nothing has changed with the newer cables, therefore, there is no reason to upgrade to newer cables unless an older 1.3 cable is defective. If you have an older 1.0, 1.1 or 1.2 cable, you will want to upgrade it to a newer 1.3 cable in order to achieve a 108p resolution and assure compatibility with newer audio and video components.
What is the maximum length for an HDMI cable?
The HDMI specifications do not limit cable length, but it is intuitive that long cable runs will lose signal strength. The longer the cable length, the higher the quality requirement become in order to prevent signal degradation or loss. Devices such as HDMI repeaters are available that amplify a signal when very long cable runs are required. There are also special cables with built-in signal amplifiers called active, boosted, amplified or equalized cables that are powered by the HDMI wiring and therefore do not need an external power supply.
Although I have not tried it, from what I have read it is safe to use cables without amplification for runs of up to 10 meters (32.8 feet). It is interesting to note that an AV amplifier with HDMI connectors is considered to be a repeater.
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Improving 3D Movie at Home |
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3D movies can be a special treat for anyone who loves special effects. The selection of 3D movies available on DVD and Blu-ray is very limited, because a 3D movie has to be filmed using special 3D cameras and techniques. Many people who view 3D movies are dissatisfied with the quality. Ghosting, loss of colors, strange flashes of color, and other anomalies are frequent complaints. Here is how to configure your television for the best 3D effects.
3D movies available for home viewing are currently limited to either anaglyph 3D technology or LCD shutter 3D technology. This article covers anaglyph 3D technology, which requires the use of special colored lens glasses in order to view the 3D effects. It focuses on issues with LCD and plasma HDTVs, although you can apply the techniques to other display technologies if you are experiencing problems.
You will probably experience the best 3D effects with a properly configured HDTV. Older televisions may work, but your options for configuring a special viewing mode for 3D movies are limited. Bringing out the 3D effects while limiting the negative effects of anaglyph technology can be difficult and you may have to experiment. The point is that an optimal screen configuration for viewing movies and television programs is not an optimal configuration for viewing 3D movies using anaglyph technology.
There are two major issues associated with viewing movies using anaglyph technology. The first is the loss of color. That issue cannot be overcome because you are viewing a movie through special glasses with two differently colored lenses. The colored lenses filter out most of the screen colors, so you may have to get used to viewing 3D movies in what is essentially black and white with some colors.
The second issue is ghosting. Ghosting is the most distracting aspect of anaglyph 3D movie technology. Anaglyph technology uses two offset images to produce the 3D effects. The closer objects will have a greater offset (greater distance between images) in order to simulate our stereoscopic vision. One image is intended for left-eye viewing and the other for right-eye viewing. So you are basically dealing with two images on the screen. Ghosting occurs when you can see both images on the screen while using anaglyph glasses. This issue can be overcome, or at least minimized to the point of being almost unnoticeable.
In order to cure a ghosting problem you will need to configure a separate display mode for viewing 3D movies. Most HDTVs have separate display modes that can be switched. Sony display modes typically include Standard, Cinema, Custom and Vivid. The names for the display modes for different brands may be different. Standard and cinema are most commonly used for viewing standard movies. 3D anaglyph technology requires brighter colors and a slightly higher contrast in order to minimize ghosting. While you may think this would make the problem worse, it has the has the opposite effect because brighter colors are a better match for the colored filters in the anaglyph glasses.
Each display mode is configurable, so read your television’s manual to determine how to change the settings. You may have to experiment to obtain the best effect.
When changing configurations, make sure that the room lighting is the way it would normally be when you are watching movies. In other words, if you view movies in the evening in a semi-dark room, do not configure the television during the middle of the day when the room may be very bright. In general, a semi-dark room using normal room lighting will work the best for viewing 3D anaglyph movies on an LCD or plasma television.
There are three settings that need to be altered. The picture (contrast), brightness and color saturation settings all need to be increased to levels higher than a normal viewing mode. If your HDTV includes a configuration for the backlight brightness, you may want to increase that, as well. Be aware that if you increase the settings too much, you will lose the details in your 3D movies and they will begin to look like cartoons.
If your HDTV has a Vivid display mode, the configuration may already be pretty close to optimal for viewing with anaglyph glasses, because this mode normally uses higher settings for picture (contrast), backlight brightness, brightness, color and sharpness. Try that mode first. if you are not having a ghosting problem, then your task is completed.
If you are still having a ghosting problem, then try the following configuration changes until the problem is resolved. One setting can effect another, so you should write down the normal settings before you make changes.
First, increase the Brightness. If your LCD television has a Backlight setting, increase that, as well.
You will have to read your manual to find out which configuration improves the contrast. For most HDTVs, this is called the Picture setting. This needs to be increased. In Vivid mode on my HDTV, this is set to Max, which is the highest contrast setting.
The Color setting increases the color saturation (intensity). This means that reds become redder, blues bluer, etc. Increase this until ghosting disappears.
The trick for configuring optimal settings for your 3D anaglyph movies is to find the right combination of settings that produces the best results for your home theater. With growing trend towards 3D, it is good to prepare some business checks to upgrade your office or home products.
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Relationship Between HDTV Refresh Rate and Frame Rate |
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When selecting the right HDTV for your home theater, it is important to understand the relationship between film frame rates and screen refresh rates. There is an interaction between the two that plays an important role in the quality of the video displayed on your HDTV.
The refresh rate is the number of times per second that a screen image is refreshed. This is similar to the frame rate found with film. The refresh rate is expressed in hertz (Hz). Hertz simply refers to the frequency or cycles per second. Most high definition televisions have a refresh rate of 60Hz, which means that a new image is displayed 60 times per second. A few of the newer HDTVs have refresh rates of 72Hz and many high-end models have 120Hz refresh rates.
There is a mismatch between the standard refresh rate of 60Hz and the frame rate of films. Movies are still filmed with a frame rate of 24 frames per second or 24fps. From what I have read, this goes back to the days of hand crank cameras and when someone determined that 24fps was the speed at which films no longer looked choppy. Most DVDs, including Blu-ray discs are recorded at this frame rate. The problem is that the standard frame rate of film does not match the refresh rate of HDTVs.
The solution used by HDTVs is to use what is called a 3:2 pulldown, which means that one frame is displayed two times, while the next is displayed three times, and the next two times, and the next three times, etc., etc. With 60Hz this happens so fast that your eyes don’t notice it, except when there is a lot of motion on the screen, which can create a phenomenon called judder. Judder occurs when the motion appears shaky. You can sometimes really notice this in an action flick when a busy background, such as a jungle scene, is in motion. Judder was very apparent in some of the Coliseum scenes in the move Gladiator. If you wondered why some of the scenes on your TV looked like they had a strobe effect, blame it on judder.
These issues are not apparent when video is used, rather than film. Film is still required for theaters, but video is much easier to work with for television. Many of the shows on television are video taped. Video frame rates can be 30fps or 60fps. Because 30 and 60 divide evenly into 60, there is no judder and action shots appear very smooth.
The 72Hz Refresh Rate
Pioneer has introduced a new plasma technology that uses 72Hz. I understand that it can detect the frame rate and can switch back and forth between 60Hz or 72Hz based upon the incoming signal. Why 72Hz? 24 x 3 = 72. Action therefore appears much smoother. When the frame rate is evenly divisible into the refresh rate, it is referred to as playing at a native playback. The action in native playbacks is always smoother.
120Hz Refresh Rate
120Hz high definition televisions can be found at the higher end of the market. Sony’s XBR4 LCD HDTVs use a 120Hz refresh rate. Why a 120Hz refresh rate when only 24 frames per second can be displayed? 120Hz displays all the frame rates with native playback. 24 x 5 = 120, 30 x 4 = 120, and 60 x 2 = 120. Regardless of the frame rate, the video is always displayed in a native playback.
Sony has taken this one step further and uses interpolation to smooth the actions scenes even further. Interpolation compares two adjacent frames and creates “filler” frames in between that basically averages the two and creates a new frame. Rather than displaying a movie frame for five cycles, interpolation modifies the frames so that one blends more smoothly into the next. This tends to make the wildest action scenes silky smooth.
I hope this helps you to understand the issues between frame rates and refresh rates and helps you make a better decision about your HDTV purchases.
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3D Movie Technology is Coming in 2010 |
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Sony, Samsung, Panasonic and other HDTV manufacturers appear to be positioning themselves for new 3D movie technology introductions in 2010.
Several recent articles on consumer electronics web sites and news sites indicate that major television manufacturers are getting ready to introduce new 3D movie features for home theaters in 2010. At the 2009 Consumer Electronics show, we saw several HDTVs demonstrating 3D movie technology. Sony, Samsung and Panasonic each displayed 3D movie and gaming technology, but each used prototype televisions, not actual models ready for the market.
Samsung and Panasonic displayed 3D models using LCD shutter technology, which requires an emitter that synchronizes high speed LCD shutter glasses with alternating left-eye, right-eye images on an HDTV using a 120Hz or 240Hz refresh rate. Sony’s approach was different from that of the others, and they would not talk about the technology. Rather than using shutter technology, the Sony demonstration used polarized glasses from RealD. The speculation at the show was that Sony was using a dual-layer LCD display, or perhaps was alternating the polarization of the images on the screen. Both the LCD shutter technology and Sony’s top secret approach worked very well. The images were crisp and displayed great 3D depth without the ghosting problems that are common to the anaglyph 3D movie technology currently available for home viewing. Panasonic’s and Samsung’s LCD shutter technology was particularly impressive and was every bit as good as the RealD circular polarized technology found in movie theaters.
The technology to produce high quality 3D movies for home viewing is available today. What is holding things up is a standard for 3D movie technology. The industry obviously wants to avoid a technology war similar to the Blu-ray and HD DVD battles. A lot of companies were badly burned when they supported the wrong side of that debate. Several HDTV models from Mitsubishi and Samsung that are already available boast that they are 3D-ready, but that claim is questionable because no standard has been set.
A group called the 3D@Home Consortium and Korea’s 3D Fusion Industry Consortium recently announced that they have teamed up to form a 3D DVD home viewing standard. The 3D@Home Consortium has consumer electronics manufacturing members from Asia, USA and Europe, which makes them the ideal group to form a standard. In the USA, the Society for Motion Picture and Television Engineers is working on a standard to be used in the future for broadcasts. Because 3D broadcasts would require a lot of bandwidth that is not currently available in many areas, 3D broadcasting is probably several years away and will likely follow the standards set for DVD viewing.
Everyone could win if a standard is established that will work with standard HDTVs. The difficult part will be in adapting current HDTVs to use the new standard, or at least find a way to attach an emitter to current models so that shutter technology could be used to synchronize television images with wireless shutter glasses. If the new standard requires everyone to buy a new and expensive 3D HDTV, it will take many years before 3D home movies can become successful because most people will not replace newer LCD and plasma televisions just to gain 3D capabilities. The solution has to be fairly simple and not too expensive.
I suspect that we will see new 3D television models introduced at the upcoming January 2010 Consumer Electronics Show. The difference from last year will be that this time the manufacturers will likely have actual 3D HDTVs and devices that are ready for production.
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