Thursday, February 19, 2015

DVI-D to VGA Converters

In fact, even though digital monitors and computer systems have become affordable, some legacy software or hardware systems can only work with VGA monitors. Sometimes, the software needs to be upgraded or even be replaced. Generally speaking, the cost of upgrading the software will be rather high. 

Therefore, people are in need of finding a most affordable solution in terms of dealing with such problem. Fortunately, the DVI-D to VGA converter has been invented to help people solve this tough issue. DVI, short for digital visual interface, is the standard interface for high-performance connection between PCs and flat panel displays, CRT displays, projectors, and HDTV. 

DVI converters are designed by people in order to convert video signals from one device to another device with a non-compatible signal format. The source computer connection and target monitor connection have great influence on your choice of converter. To be honest, it won’t work if you just buy some cheap DVI to VGA adapter plug. To cope with the compatibility issue, the first step you are supposed to take is to identify what your computer uses, namely, whether it uses DVI-D, DVI-A, DVI-I, VGA or HDMI connection. Next, you should figure out the video connection type on monitor or projector.

Generally speaking, a DVI-D to VGA Converter is much more preferred by people as it is a very affordable alternative in comparison with costly software or hardware upgrades. If you don’t want to replace or upgrade operational VGA monitors and legacy systems, a DVI-D to VGA converter is an ideal solution. On the other hand, this can also help you save more money in the future for it can postpone other costly expenditures. Above, such converters really help to extend the life of your equipment and save your money to a rather large degree.

Wednesday, February 18, 2015

VGA to DVI Converter Box

Generally speaking, analog and digital signals are delivered in quite different modes. As a result, there will be some compatibility issues between electronic products. The VGA to DVI conversion is necessary when the analog signal has to be converted into digital signals.

Mixing analog and digital signals require a supporting device. We can take a VGA graphics card and a digital flat screen sign as good examples. The VGA to DVI-D converter is such a device, which is necessary equipment when you are not able to change the graphics card or the computer. People can get important information such as maps, directions or notifications from the digital center. Such display tools are very common in hospital or airport. To be honest, this is similar to a bulletin board. The only difference is that it has a screen used to present text data and images, which can make it seem like a television display. As a matter of fact, such presentation on the digital message center is changed through some program using software on a control station, typically a computer.

When the signage has to be upgraded, some change will occur in the control station. When the new signage is digital while the controlling computer has a VGA connection, the compatibility issue will emerge. Therefore, a VGA to DVI conversion is required to realize in order to make the sign to be properly received and the signal sent from the control station to be properly presented.

Here is the good news. The VGA to DVI conversion is far more readily available and affordable than upgrading the hardware on the control station. In fact, the operating system and software have to be upgraded to accommodate the new hardware under some circumstances. A VGA to DVI-D converter is much more economical and faster than upgrading hardware and software on the control station.

Tuesday, February 17, 2015

Decide Between VGA, DVI, and HDMI for Your Monitor Connection

It is of great importance for people to know exactly what type of output ports the computer supports when they are deciding to buy it. After all, what they want is just to be able easily hook up to the computer monitor, or the projector no matter where they are. Therefore, it is advisable for people to make their decisions in a careful way after serious considerations.

As a matter of fact, there is no clearcut standard for video connectors. Therefore, most projectors and even lots of displays have multiple input ports. Generally speaking, there are multiple standards of computer video cables, namely, VGA, DVI and HDMI. In effect, each of them has its own advantage and they are still in competition in order to win people’s favor.

VGA cables can only carry analog signals. As a result, the analog signal sometimes needs to be converted into digital signals, which may lead to some quality loss of the vide source. On the other hand, it’s possible to reach a relatively high range of video resolutions because of using higher frequencies.

DVI, one of VGA’s successors, is appearing more and more on computers and displays, especially on higher-end graphics card and high-resolution computer displays. However, DVI is not considered as the mainstream connector as VGA.

In addition, there are several types of DVI connectors which can handle uncompressed digital video. Therefore, the video quality does not depend on the cable very much. It is safe to say that the video quality can be better in this way.

If DVI is considered to be the successor to VGA, then HDMI is possible the successor to DVI. HDMI enjoys a better fame in comparison with DVI possibly as it often appears on high definition televisions. In effect, HDMI is compatible with newer televisions, which makes it more and more popular in the electronics market. Its compact size is more and more often showing up in computers and computer displays as well.

Monday, February 16, 2015


A variety of cables have been adopted by people in daily life and work in order to transmit sound and video quality to one another in computers and televisions. VGA and HDMI are two of those cables and video standards. They are used to hook computer up to the television, which can help people enjoy the video on the television after transmitted from their computers. Therefore, it is safe to say that they are of great use in people’s daily life. If you want to put a movie onto the TV or if you are in need of showing a PPT or slide to a group of friends or family or for a business meeting, then they will help you in many ways.

As a matter of fact, VGA and HDMI cables have two different types of video standards. The VGA is an analog standard which can be used with things like S-Video, radio frequency, D-Terminal and even component video, etc. on the other hand, HDMI is able to connect digitally with audio and video sources like Blu-Ray disc players, DVD players, HD DVD and even things like computers, video game consoles and camcorders.

VGA cables can only offer the video signal. Any other signals including audio can not be offered through VGA. On the other hand, HDMI can offer both video and audio signals. This difference has a lot of influence as you can decide whether you need other cables, connectors or even adapters under some circumstances. As a result, you are supposed to equip an adapter with audio cables when you want to watch movies on the television from your laptop with only a VGA cable. However, if you have an HDMI cable, then you have nothing to worry about when watching the movie on the television from your laptop.

Sunday, February 15, 2015

Difference between DVI and VGA

Generally speaking, VGA and DVI connectors are both powerful tools in terms of transmitting video from a source, fro example, a computer or tablet, to a display device, like a monitor, TV or projector. As a matter of fact, the main difference between VGA and DVI lies in how the video signal travels. In effect, VGA connectors and cables are able to carry analog signals while DVI can carry both analog and digital signals. In comparison, DVI is a newer technology which is capable of offering people better and sharper display. Fortunately, it is easy for people to distinguish DVI and VGA as they have obvious physical difference: VGA connectors and ports are blue while DVI connectors are white.

On the other hand, DVI can offer a higher quality signal than VGA. The higher the resolution is, the more noticeable the difference will be. After all, the quality of the video depends on the operation mechanism and the length and quality of the cable. 

However, the operation mechanism of VGA and DVI has no difference for users. Actually, they have no desire to understand the difference between them. For them, both connectors work in the same way: devices have female ports and the connectors have male endpoints.

In application, the operation of VGA and DVI has much difference which happens in the data transmission process. VGA connectors transmit analog signals. As a result, the digital video signal received from the source will be converted to analog signals in order to be transmitted via the cable. When the display device is an old CRT monitor, then it is able to accept the analog signal. However, the majority of display devices used today are digital. Therefore, the analog signal of the VGA connectors will be converted to digital signal in the end. In consequence, the video quality for VGA connectors will suffer some kind of degradation.

Saturday, February 14, 2015

Image Cropping

If you are starting with digital images or having trouble getting started, then there is some knowledge you need to master. To view digital images on the video screen, people are supposed to have a good understanding about how to deal with digital images. It is of great use to learn some basics about resizing digital images. In effect, it is like learning to drive. Once you have mastered the necessary knowledge, which is not difficult at all, you will benefit from it for the rest of your life. Therefore, here is the knowledge prepared for you in order to master the required basics. 

As a matter of fact, digital image size is dimensioned in Pixels. Pixels are what it is all about and digital is rather different from film. Resize is a term which seems a little vague and ambiguous. It does not have specific meaning until we tell what it means exactly. There are several ways to resize an image and each will lead to different results.

First of all, we are going to talk about how to crop an image. Image cropping refers to the way to simply cut away some at the edges and include less area in the final image. It is like the actions done by scissors on paper, so to speak, what’s different is that we will enlarge the image later. The trimmed pixels will be discarded after the image has been cropped, which makes the image dimensions smaller. As a result, it can change the scene included and the shape from time to time. Frankly speaking, a little cropping is helpful to improve the composition of many images as well as remove the uninteresting blank nothingness around the edges and concentrate the actual subject larger.

Friday, February 13, 2015

How to Scale an Image

Generally speaking, there are three main types of algorithms which can be made use of by people in the process of image scaling to increase the size of an image. First of all, the simplest method is to take each original pixel in the source image and then copy it to the corresponding position in the larger image. Some gaps between the pixels in the larger image may appear, but they can be filled by assigning to the empty pixels to the color of the source pixel to the left of the current location. As a matter of fact, such operations can multiply an image and its data into a larger area. This method, called nearest-neighbor, is very useful in terms of preventing data loss, but the image quality usually suffers some damage as the enlarged blocks of individual pixels will be clearly visible.

There are also some other image scaling algorithms called bilinear interpolation and bicubic interpolation. They work by filling in the empty spaces in an enlarged image with pixels whose color is determined by the color of the given pixels surrounding it. Under such conditions, the scaled image will be smoother than the scaled image using the nearest-neighbor method, but the image may suffer from some other problems, including becoming blurry and full of indistinct blocks of color.

The third type of image scaling algorithm makes use of pattern recognition to identify the different areas of an image being enlarged. Next, it tries to structure the missing pixels. This method will bring people a lot of benefits. However, the more times the image is scaled by this algorithm, the more visual artifacts will appear. In addition, this method requires more money than other types of scaling when scaling full-color photographic images, which makes it more computationally expensive under some circumstances.

Thursday, February 12, 2015

Image scaling

Scaling is also known as Resize. Sometimes, Resample is even called scaling, which is not entirely unreasonable. Image scaling refers to the computer graphics process which increase or decrease the size of a digital image. As a matter of fact, an image can be easily scaled by an image viewer or editing software. In addition, an image can also be scaled automatically by a program, which can greatly help the image to fit into an area of different size without efforts. People can make use of a lot of methods in order to reduce an image. However, the most popular way adopted by people is a type of sampling called undersampling, which can help to maintain the original quality. It is more complicated to enlarge an image as there is larger area to be filled with more pixels. 

Generally speaking, scaling is a non-trivial process which involves a trade-off between efficiency, smoothness and sharpness. With bitmap graphics, the pixels forming the image will become more and more visible when the size of the image is being reduced or enlarged, which can make the image seem “soft” if the pixels are averaged or jagged. 

In effect, scaling will not change the image pixels in any way. To be honest, scaling will only change the single number of dpi (ppi), a number simply stored separately in the image file in an arbitrary way. The only equipment makes use of it is the printer. What’s more, it only changes the size the image will print on paper. The images on the computer screen will not be influence by the number at all. Actually, the camera can never know how people want to print the image, and thus just makes up a number. As a result, people are supposed to fix the number before printing anything.

Wednesday, February 11, 2015

About Black Bars

Generally speaking, there are some common problems associated with aspect ratio. For example, the video seems stretched horizontally or vertically when you play it on your DVD player. Fortunately, such problem can be easily handled by tweaking hardware settings. Users just need to configure the DVD player or TV set to the correct aspect ratio in order to make the video as normal. 

In addition, there is one problem related with aspect ratio. People will encounter with it from time to time when playing video. How to remove the black bars from the edges of the video when you are playing the video? 

As a matter of fact, black bars often happen when a widescreen video (16:9) is converted to 4:3 if the user is making use of the Letter Box resize method. To be honest, the proportions of the image have nothing uncommon, but there are black bars existing on the top and bottom of the video. If you are watching video on a widescreen TV, then this problem will lead you to feel a little bit uncomfortable and distract you to a large extent. The TV adds its own bars to the sides of the video to display it on the screen. 

On the other hand, black bars will appear on the left and right sides of the video image when a 4:3 video is converted to 16:9 using Letter Box resize method. In this case, users can make use of the Crop resize method in order to get rid of the unwanted black bars and return the video to 4:3 aspect ratio eventually. Moreover, people can also remove the unwanted black bars by adopting some professional software designed to perform some very powerful functions. In the end, the video will be displayed normally and people can enjoy watching it without being distracted by the black bars.

Tuesday, February 10, 2015

Hardware Compression vs. Software Compression

Software compression is more well-known among people when compared with hardware compression. The reason is that the majority of people do not have need to apply hardware compression in their daily life. In contrast, software compression does meet their requirements in many aspects. Generally speaking, software compression is cheaper and more easily accessible solution compared with hardware compression. On the other hand, hardware compression demands specialized equipment which is designed to deal with specific workload. Even though hardware compression costs users more, it does have its own advantages over software compression. First of all, the specialized hardware enables hardware compression to be faster than software compression to a great degree. Software compression just requires a general purpose processor in order to perform its job. Secondly, hardware compression will not cause any extra burden to the host processor because its calculations take place within its own hardware. Software compression cannot make it. Under most circumstances, software compression is likely to degrade the performance of the host during heavy use and other operations. If you are compressing a large amount of data while using your computer at the same time, then this may pose a great threat.

There is no doubt that software compression has advantages as well. First, it costs less. Second, software compression offers users a lot of options to choose from. Users are allowed to control the process of how the data is archived, compressed and formatted. In comparison, users are given very few, or no options at all with hardware compression. Users have no say in the process of how the data is compressed before being stored into the media. Everything has been pre-programmed into the hardware by the manufacturer.

In conclusion, software compression is better if you are going to store compressed data for a long time. Hardware compression is usually device specific, which may cause great problems when your device fails without anything can replace it.

Monday, February 9, 2015

Hardware Compression

Generally speaking, the hardware compression is performed on the data path level. As a matter of fact, the hardware compression is only available for the data path which directs data to tape libraries. Under this circumstance, the uncompressed data will be sent from the client computer to the media through the data path. Therefore, the data will be compressed by the tape drive hardware before being written to the media.

There is no doubt that hardware compression is faster than software compression most of the time. The reason is that hardware compression is operated by dedicated circuitry. As a result, the hardware compression is ideal for direct-connect configurations in particular where the subclient and MediaAgent are hosted by the same physical computer. In such configurations, the drives are able to compress the data at the same rate as it is sent by the subclient as there are no network bottlenecks throttling the data transmission to the media drives. On the other hand, the hardware compression can boost the virtual capacity of the tape but also the performance of the data protection thanks to the tape storing more data per unit with higher operation speed. 

However, the problem is that hardware compression is not supported by disk library. It is only applicable for tape libraries.

If the data secured by data protection operations must compete with other data for network bandwidth, then hardware compression may be not that useful. When the network is congested, the tape drives will be starved for data for the data cannot be supplied quickly enough. Under such circumstance, the drives can compress as well, but the drives are likely to stop and restart the media in order to wait for more available data. Therefore, the compression performance may not be very ideal, which may lead to some potential problems.

Sunday, February 8, 2015

Software Compression

Client Compression

The client compression is specified on the subclient level for most agents. Generally speaking, it is available for all storage media. If people adopt this way, then the data on the client computer will be compressed using the compression software. Next, the compressed data will be sent to the MediaAgent that directs it to the storage media in turn. When the client and MediaAgent reside on separate computers and the client has no choice but to send the data through a network, then client compression will be of great use and convenience for it can reduce the network load to a large extent.

Replication Compression

Replicated data can be compressed between the source and the destination computer. If the compression is enabled, then the data will be compressed on the source computer, replicated across the network to the destination computer and uncompressed on the destination computer, which can reduce the workload of the network to a rather large degree. As a matter fact, replication compression is specified on the Replication Set level and applies to all of its Replication Pairs. Therefore, people have the capability to enable or disable client compression between the source and destination machines for a given Replication.

MediaAgent Compression

The MediaAgent compression is specified on the subclient level for most clients. If the data path does not have hardware compression enabled, then people have the capability to enable or disable MediaAgent compression for a given subclient or instance as appropriate. 

Actually, MediaAgent compression is available for all storage media. The data will eb compressed on the MediaAgent using compression software in the MediaAgent. Afterwards, the compressed data will be sent from the MediaAgent to the storage media. When the MediaAgent software resides on a computer more powerful than the client computer, then the MediaAgent Compression can be of great use and convenience.

Saturday, February 7, 2015

Data Compression

Data compression options are provided for data which is secured by data protection operations. Generally speaking, compression is a very useful way to reduce the quantity of data sent to storage, which will double the effective capacity of the media in return (depending on the nature of the data). Moreover, the system will automatically decompress the data and restore it to the original state when the data is later restored or recovered.

The following data compression options are provided: software compression and hardware compression. Software compression offers users to compress data in the Client and MediaAgent while hardware compression for libraries with tape media at the individual data path. In addition, as compressed data often increases in size if it is again subjected to compression, the system will apply one type of compression for a given data protection operation. Therefore, users are able to redefine the compression type at any time without damaging the ability to restore/recover the data.

If the hardware compression is available and applied, then it will have some kind of priority over the other compression selections. Whenever hardware compression has been enabled for a data path, all data conducted through the data path will be compressed in the way of hardware compression automatically. Otherwise, the data will be dealt with in accordance with the software compression selection of each subclient which backs up to the data path. Under such circumstances, people are able to choose from the following options: Client compression, MediaAgent compression, or no compression.

Last but not least, bear in mind that hardware compression is not applicable for disk libraries. As a result, the software compression selection for subclient is adopted by people for data paths which are associated with disk libraries. It is advisable to have a good understanding of such knowledge before compressing data.

Friday, February 6, 2015

Different Effects for Different Parts of an Image

It seems that brightness, contrast, saturation and sharpness are the four simplest controls of image. On the surface, they are four mutually exclusive controls. However, as a matter of fact, they are related to each other and intertwined in a way to such a degree that the change of any one of them will lead to rather complicated effects in the image in terms of the other three controls. Only when users have mastered a rather good knowledge about how these four controls are related and how to make use of them in a harmonious way can users achieve the desired image effects in the end. It is wise for users to think twice about what they really want to accomplish before taking actions to change the brightness, contrast, saturation and sharpness, whether to increase or to reduce them.

Generally speaking, the overall effect of brightness, contrast, saturation and sharpness varies according to different contents in the photo. Take the increase of contrast as an example. With the increase of contrast, the shadow will be darker while the highlight will be brighter. However, if most details in the photo are very bright, for instance, an overexposed sunset, then we will end up with less contrast with the increase of its contrast. The reason is that there is no shadow in the photo at all, which means that the separation of shadows and highlights in an image containing only highlights will just compress the highlights. As a result, the image will get less contrasty. We can safely come to the conclusion that it is vital to have a good understanding about how these four simplest controls affect each other and how they work in a harmonious way. It is a bit of art to use brightness, contrast, saturation and sharpness to achieve a balance.

Thursday, February 5, 2015


Generally speaking, brightness, contrast, saturation and sharpness are thought to be the four simplest controls as they have been developed as long as the color TV was invented in the first place. However, people often turn blind eyes to the fact that all these four controls are related to each other. As a matter of fact, changing any one of these four controls will influence and change the other three. 

People may tend to define sharpness as edge contrast, in other words, the contrast along edges in a photo. It is reasonable for people to have such definition. The fact is that an increase of sharpness will lead to the increase of the contrast between only along/near edges in the photo while the smooth areas of the image will not be influenced at all.

When you have made use of the tool of unsharp mask, you will only change the sharpness of the edges. In effect, different parts of the same image will show different change of their sharpness. As a matter of fact, where the edge is thicker, the sharpness will be increased while the contrast and brightness will not have obvious change at all. If the edge is rather thin, then the contrast, brightness and saturation will be greatly increased with the increase of the sharpness. Therefore, it is safe to conclude that increasing sharpness can cause the appearance of increase saturation, contrast, and brightness in areas of the image which contain fine detail where other areas (areas with broader detail) seem less affected except for the added sharpness. In all, changing one of these four controls really affects the other three most of the time. Keep in mind that you need to strike a balance between them; otherwise, the image will make people feel uncomfortable.

Wednesday, February 4, 2015


Saturation has a lot of similarity with contrast. However, saturation will increase the separation between colors instead of increasing the separation between the shadow and highlight. As a matter of fact, if the specific part of an image has its own saturation and some parts have no saturation at all, then an increase in saturation will lead to the increase in contrast, brightness and sharpness of the part which has its own saturation as well. On the other hand, the contrast, brightness and sharpness of part having no saturation will not change at all. Similarly, a change in saturation will have a more noticeable effect on the vibrant color and less on dull color or colors that are almost neutral. The reason for such phenomenon is that color saturation can be changed only when there is color saturation to work with in the first place.

In all, changing one of these four controls really affects the other three most of the time. Keep in mind that you need to strike a balance between them; otherwise, the image will make people feel uncomfortable.

Tuesday, February 3, 2015


Generally speaking, brightness, contrast, saturation and sharpness are thought to be the four simplest controls as they have been developed as long as the color TV was invented in the first place. However, people often turn blind eyes to the fact that all these four controls are related to each other. As a matter of fact, changing any one of these four controls will influence and change the other three.

An image must have the proper contrast for easy viewing. Contrast refers to the difference in brightness between objects or regions. For example, a white rabbit running across a snowy field has poor contrast, while a black dog against the same white background has good contrast. Contrast is specifically defined as the separation between dark and bright, which means that shadows can be darker and highlights can be brighter by changing the contrast. On the other hand, you can decrease the contrast in order to bring the shadows up and the highlights down, which can make them closer to each other. As a matter of fact, adding contrast usually makes the image more popular because it seems more vibrant. In comparison, the image will look duller and boring if the contrast has been decreased to a great degree.

When you have added contrast to an image, then you will notice that some part will become darker while some parts become brighter. This can make the image look more defined. Meanwhile, you have also increased the brightness of some parts. Besides, the saturation of the brighter and darker parts will be increased, which also increases the sharpness. Therefore, it is rather obvious that the four controls do affect each other. Changing of one will also lead to the other three to have corresponding changes. Keep in mind that you need to strike a balance; otherwise, the image will be uncomfortable.

Monday, February 2, 2015


Generally speaking, brightness, contrast, saturation and sharpness are thought to be the four simplest controls as they have been developed as long as the color TV was invented in the first place. However, people often turn blind eyes to the fact that all these four controls are related to each other. As a matter of fact, changing any one of these four controls will influence and change the other three. Do you have any knowledge about how they are related and how to change the balance of brightness, contrast, saturation and sharpness by only changing one of these three parameters? Here is some knowledge you might have desire to know.

An image must have the proper brightness and contrast for easy viewing. Brightness refers to the overall lightness or darkness of the image. Most people tend to think that brightness is the simplest control of image in concept. They believe that changing of the bright just means the image will be brighter or darker. In order to remove such misunderstanding, we need to distinguish brightness from “gamma” in the first place. Actually, increasing gamma by moving a mid-tone slider on a histogram is not the same as increasing brightness. We can’t but admit that increasing gamma/mid tones really makes an image look brighter, but it is non-linear because it only increases the brightness of the shadows and mid-tones instead of influencing the highlights in the image. On the other hand, traditional brightness equally brightens the entire image from the shadows to the highlight in a simple way.

As a matter of fact, if we add too much brightness, then the shadows will catch up to the highlights as they are already as bright as they can get. As a result, the contrast, saturation and sharpness of the image will be reduced accordingly. Therefore, changing one of these four controls really affects the other three. Keep in mind that you need to strike a balance; otherwise, the image will be uncomfortable.

Sunday, February 1, 2015

The Difference between Interlaced and Progressive Video (Ⅱ)

In comparison, progressive video is made up of consecutively displayed video frames. All the horizontal lines consisting of the image being shown are contained. Therefore, progressive video has some advantages over interlaced video. For example, images will be smoother, fast-motion sequences are sharper and artifacts are much less prevalent.

Nonetheless, progressive video has some drawbacks as well. People have found that progressive video demands higher bandwidth, which may lead to some problems if this requirement cannot be satisfied. With the development of science and technology, such problems cannot pose threat to the application of progressive video for a lot of more advanced technological products keep emerging. Nowadays, television systems and packaged media such as DVD are moving away from analog transmission and storage. Instead, the digital variants are becoming more and more popular. Under such circumstances, people have the opportunity to apply more efficient video compression most of the time. As a result, with the same amount of bandwidth, higher resolution images can be achieved than possible via interlaced analog video.

As a matter of fact, interlaced video will also be applied for a long time even though progressive video is more convenient and popular. The reason is that broadcasts in the US and some other countries still make use of 1080-line interlaced HD format. Nonetheless, both displays and packaged media are moving toward progressive video formats as the exclusive video at the same time, such as 720- and 1080-line progressive formats.

Actually, all digital, non-CRT displays can only display progressive video. As a result, any interlaced video cannot be displayed on them before being de-interlaced or converted. Interlaced video signals have to be deinterlaced or converted to progressive video. With time going on, it is possible that progressive video will totally take the place of interlaced video in every type of device since progressive video is more convenient and beneficial to people. 

Saturday, January 31, 2015

The Difference between Interlaced and Progressive Video (Ⅰ)

There is no denying that the interlaced format is the earliest known form of video compression. As a matter of fact, it is developed in order to address early TV technology challenges and broadcast bandwidth constraints. However, interlaced video was not perfect enough to satisfy people’s various requirements. Therefore, the progressive video was developed as a newer technology which can help meet people’s requirements under specific conditions.

As for interlaced video, each field of a video image displays every other horizontal line of the complete image. For instance, in the first field of the interlaced video, the even-numbered lines will be displayed, and then the odd-numbered lines of the same image will be shown with the second field of the same interlaced video. If this even/odd sequence is repeated frequently enough, for example, 25 to 30 times per second, then the viewer will be able to see the complete moving image with the help of the persistence of human vision.

It is well known that the interlaced video allows more detailed images to be created than would otherwise be possible within a given amount bandwidth, which is its main benefit. As a matter of fact, a doubling of image resolution is also allowed in interlaced video. However, there are also some problems which cannot be ignored. In the first place, interlaced video comes with real-world downside. On the other hand, image softening will take place during fast-motion sequences. In addition, moiré or strobing artifacts are likely to occur in the process of showing striped shirts, plaid jackets, bricks in a building or similar types of objects.

In comparison with interlaced video, progressive video has greatly gotten rid of such problems and thus enjoy more popularity among people. It is possible that progressive video will play a more important role than interlaced video in the future.

Friday, January 30, 2015

Advantages of Progressive Scan

Generally speaking, progressive scanning has its own advantages when compared with interlaced scanning. First of all, the main advantage with progressive scanning is that the motion will be smoother and more realistic. In contrast, the interlaced video of the same rate will have a lot of visual artifacts, such as interline twitter. When capturing video with progressive scan, people have no such worries. It is safe to say that there will be an absence of visual artifacts, which enables the captured image to be used as still photos.

As a result, there is no need in intentional blurring, namely, anti-aliasing, of video in order to reduce interline twitter and eye strain. As a matter of fact, in the case of most media such as DVD movies and video games, the video is automatically blurred during the authoring process itself to subdue interline twitter when played back on interlace displays. Therefore, it is entirely impossible to recover the sharpness of the original video if the vide has been viewed progressively. A feasible solution to this problem is that people are supposed to choose the display hardware and video games come equipped with options to blur the video at will or to keep it at its original sharpness. Under such circumstance, the viewer is able to achieve the desired image sharpness no matter whether he is adopting interlaced or progressive displays.

Actually, progressive video is clearer and faster for scaling to higher resolutions in comparison with its equivalent interlaced video. HDTVs not based on CRT technology cannot natively display interlaced video. Therefore, the interlaced video has to be deinterlaced before it is scaled and displayed on HDTVs. However, in the deinterlacing process, some noticeable artifacts and input lag between the video source and display device are likely to emerge.

Thursday, January 29, 2015

About Progressive Scan

Progressive scanning refers to a way of displaying, storing or transmitting moving images in which all the lines of each frame are drawn in sequence. It is also known as noninterlaced scanning alternatively. In comparison with interlaced video, progressive scanning is a way distinguished from interlaced scanning. Interlaced video is usually adopted in traditional analog television systems in which only the odd lines, then the even lines of each frame (each image called a video field) are drawn one after another. As a result, only half of the number of actual image frames are utilized to produce video.

As a matter of fact, progressive scanning is known as “sequential scanning” in the first place when it was adopted in the Baird 240 line television transmissions from Alexandra Palace, United Kingdom in 1936. Nowadays, progressive scanning has been universally adopted in computing.

Progressive scanning is applied in the scanning and storing of film-based material on DVDs. It was agreed that all film transmissions by HDTV would be broadcast with progressive scan in the US. Even though the video signal is sent interlaced, an HDTV will convert it to progressive scan.

Progressive scanning has been applied on most Cathode ray tube (CRT) computer monitors, all LCD computer monitors, and most HDTVs for the display resolutions are progressive by nature. Other CRT-type displays, such as SDTVs, will only display interlaced video.

Generally speaking, some TVs and most video projectors have one or more progressive scan inputs. Before HDTV became well received, some high end displays supported 480p. Under such conditions, these displays were able to be used with devices outputting progressive scan. For instance, some progressive scan DVD players and certain video game consoles are included. HDTVs support the 480p and 720p resolutions which have been progressively scanned. Compared with lower resolution HDTV models, the 1080p displays are usually more expensive. 

Wednesday, January 28, 2015

Device Driver

Device driver is usually called driver for short. Generally speaking, driver is a more popular name among people. In computing, it refers to a computer program which operates or controls a particular type of device which is attached to the computer. As a matter of fact, a driver provides a software interface to hardware devices, which enables the operating system and other computer programs to have access to hardware functions even without needing to know the hardware being used in great details.

Typically, a driver can only communicate with the device through the computer bus or communications subsystem connected to the hardware. If the routine located in the driver is invoked by a calling program, then the driver will issue commands to the device immediately. As long as the device sends the received data back to the driver, the routines in the original calling program are likely to be invoked as well. As a matter of fact, drivers are hardware-dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface. Therefore, it is safe to say that drivers are of vital significance in computing.

Device drivers act as translators working between a hardware device and the applications or operating systems using it, which can effectively simplify programming. Moreover, programmers can write the higher-level application code regardless of the specific type of hardware being used.

For instance, a high-level application for interlacing can be rather simple. It may have only two simple functions, namely, “send data” and “receive data”. However, it is able to interact with a serial port. In comparison, a device driver at a lower level may only be able to communicate with a particular serial port controller installed on a user’s computer even though it has implemented these functions as well. 

Tuesday, January 27, 2015

Where Deinterlacing Is Performed

Deinterlacing of the interlaced video signal can be performed at different points in the TV production chain.

Progresive Media

If the broadcast format or media format is progressive, then the interlaced archive programs will need the help of deinterlacing. Generally speaking, there are two ways for people to choose from in order to achieve this.

First of all, people can convert the interlaced video material to progressive scan during program production. In this way, the best possible quality is likely to be produced for videographers are capable of manually choosing the optimal deinterlacing method for each frame since they have access to expensive and powerful deinterlacing equipment and software.

Secondly, people could convert interlaced programs to progressive scan immediately prior to broadcasting with the help of real-time deinterlacing hardware. However, the conversion may be inferior to the pre-production method for the processing time is limited by the frame rate and no human input is available.

Interlaced media

Real-time deinterlacing also plays an important role in converting the interlaced video. If the broadcast format or media format is interlaced, then it can work to help people. However, the quality may be not so satisfactory because the consumer electronics equipment is rather cheap, which means that only less processing power and simpler algorithms are available in comparison with professional deinterlacing equipment.

On the other hand, what can not be ignored is the fact that the majority of users are not trained in video production, which sometimes lead to poor quality for many people have little knowledge about deinterlacing and are no aware that the frame rate is half the field rate. Therefore, deinterlacing is a very demanding work which needs to be done in a careful and patient way. Only with these efforts can people enjoy the video with the best possible quality.

Monday, January 26, 2015

Deinterlacing Methods

Deinterlacing refers to the technique which demands the display to buffer one or more fields and recombine them into full frames. Theoretically, this technique sound as simple as capturing one field and combining it with the next field to be received and then producing a single frame. However, deinterlacing is far more form simple in actual application. Generally speaking, the originally recorded signal was produced as a series of fields. What’s more, any motion of the objects during the short period between the fields will be encoded into the display. As a result, even the slightest differences between the two field due to the motion of the objects may lead to a “combing” effect in the combination process of a single frame. Therefore, deinterlacing is a very demanding technique requiring people to be careful and patient.

Actually, there are a variety of methods for people to choose from in terms of deinterlacing video. In addition, each method will cause different problems or artifacts of its own. On the other hand, some methods are much cleaner in artifacts than other methods.

Most deinterlacing techniques can be divided into three different groups which use their own exact techniques. The first group is called field combination deinterlacers. The name comes from the fact that they are able to take the even and odd fields and combine them into frame displayed later. The second group is called field extension deinterlacers for each field is extended to the entire screen in order to make a frame. The third group is called motion compensation which uses a combination of both.

Modern deinterlacing systems are able to buffer several fields and use techniques like edge detection in order to locate the motion between the fields. Therefore, this is adopted by people to interpolate the missing lines from the original field and reducing the combining effect.

Sunday, January 25, 2015

Interlacing Problems

Generally speaking, interlacing is a very useful technique developed by people with the intention of capturing, storing, transmitting and displaying the interlaced video in the exactly same interlaced format. Its wide application in today’s scienece and technology field proves that interlacing is really very helpful and thus widely accepted by people. As a matter of fact, each interlaced video frame is made up of two fields which are captured at two different times. As a result, the interlaced video frame is likely to exhibit motion artifacts. Those artifacts, known as interlaced effects, or combing, will appear when the recorded object moves fast enough to be in different positions when each individual field is captured. If the interlaced video is displayed at a slower speed than it was captured or displayed in still frames, then these artifacts will be more visible. Therefore, people are supposed to try their best to avoid these motion artifacts in order to get the most satisfactory progressive frames. Only under such circumstance can people enjoy the video of the best quality.

Fortunately, there are some both simple and useful methods which can help users to produce satisfactory progressive frames from the interlaced image. For instance, users can make use of the function of doubling the lines of one field and omitting the other, namely, halving vertical resolution, or anti-aliasing the image in the vertical axis, which will be of great use for them to hide some of the interlaced effects or combing. Sometimes, these methods can help users produce progressive frames of more satisfactory quality. Therefore, users are supposed to make the fullest possible use of these functions to help themselves produce better and more satisfactory progressive frames. With these functions and adjustments, people will have the opportunity to enjoy the video of the best possible quality.

Saturday, January 24, 2015

About Deinterlacing

Generally speaking, interlaced video can be directly displayed on ALiS plasma panels and the old CRTs. However, modern computer video displays and TV sets are mostly based on LCD technology, the majority of which adopt progressive scanning. Therefore, interlaced video can not be directly displayed on such modern computer video displays and TV sets. Under this circumstance, the technique of deinterlacing is of great necessity and value in our daily life. The process of deinterlacing plays a vital role for people to display interlaced video on a progressive scan display.

As a matter of fact, deinterlacing is an imperfect technique. Most of the time, it will lower the resolution and lead to a variety of artifacts, especially in those areas with objects in motion. Only when users are equipped with some very expensive and complex devices and algorithms can they get the interlaced video with the best picture quality. For television displays, deinterlacing systems are integrated into progressive scan TV sets that accept interlaced video.

The majority of modern computer monitors do not support interlaced video. Therefore, users have to perform deinterlacing in the software in advance, which enables the interlaced video to be played back on a computer display. Actually, the deinterlacing process often adopts some vey simple methods. As a result, the interlaced video often has visible artifacts on computer systems. Interlaced video may be edited by computer systems, but the video content being edited can only be viewed properly with the help of a separate video display hardware for there the computer video display system and the interlaced television signal format have various differences. Fortunately, current manufacture TV sets has adopted a system of a system of intelligently extrapolating the extra information that would be present in a progressive signal entirely from an interlaced original.

Friday, January 23, 2015

Brief Introduction of Deinterlacing

Deinterlacing refers to the technique of converting interlaced video. For example, when you are converting the common analog television signals or 1080i format signal into a non-interlaced form, you are performing the process of deinterlacing by your own. Generally speaking, interlaced video can be directly displayed on ALiS plasma panels and the old CRTs. However, modern computer video displays and TV sets are mostly based on LCD technology, the majority of which adopt progressive scanning. Therefore, interlaced video can not be directly displayed on such modern computer video displays and TV sets. Under this circumstance, the technique of deinterlacing is of great necessity and value in our daily life. The process of deinterlacing plays a vital role for people to display interlaced video on a progressive scan display.

As a matter of fact, interlaced video is made up of two sub-fields which are taken in sequence. Generally speaking, each of the two sub-fields is sequentially scanned at odd and even lines of the image sensor separately. This technique is adopted by the analog television because less transmission bandwidth is allowed for and the perceived flicker can be eliminated to a greater degree. Displays based on CRT were able to correctly display interlaced video because of its complete analog nature. On the other hand, all of the modern displays are designed to be digital in nature because the display consists of discrete pixels. As a result, the two fields need to be combined into a single frame, which will lead to a variety of visual defects. The technique of deinterlacing should try to avoid such conditions as much as possible.

People have been dedicated to improving the technique of deinterlacing for decades. What’s more, complex processing algorithms have been adopted as well. Unfortunately, it is rather difficult to achieve consistent results. However, we should have confidence in technologists and the more and more developed science and technology. The technique of deinterlacing will be improved step by step.

Thursday, January 22, 2015

Benefits of Interlacing

There is no doubt that the signal bandwidth is one of the most important factors in analog television. The signal bandwidth is measured in megahertz. Generally speaking, the greater the bandwidth is, the more expensive and complex the entire production and broadcasting chain are. Many kinds of digital device are included: cameras, storage systems, broadcast systems and reception systems.

First of all, interlace provides a fixed bandwidth with a video signal whose frame rate is twice the display refresh rate for a given line count. With the higher frame rate, the appearance of objects motion is greatly improved for the higher rate is able to update their positions on the monitor more often. If the object is still, then human vision will combine information from multiple similar half-frames in order to produce the same perceived resolution as progressive full frames.

Secondly, interlaced video also enables a higher spatial resolution than progressive scan. For example, 1920×1080 pixel resolution interlaced HDTV with a 60 Hz field rate has a similar bandwidth to 1280×720 pixel progressive scan HDTV with a 60 Hz frame rate, but its spatial resolution is approximately twice the resolution for low-motion scenes.

Even though interlaced video have much advantages, the bandwidth benefits can only be enjoyed by analog or uncompressed digital video signal. If the digital video has already been compressed, then interlacing may lead to some additional inefficiencies no matter what current digital TV standards it is used in. On the other hand, it has been proved that even though the frame rate can reach twice the number of the progressive scan, the bandwidth savings of interlaced video over progressive video is minimal. For instance, when encoding a "sports-type" scene, 1080p50 signal almost produces the same bit rate as 1080i50 while it actually requires less bandwidth to be perceived as subjectively better than its 1080i/25 equivalent.

Wednesday, January 21, 2015

About Interlaced Video

Interlaced video refers to the technique for doubling the frame rate of a video display without the making use of extra bandwidth. Generally speaking, the interlaced signal consists of two fields of a video frame captured at two different times. Interlaced video are powerful in function as it can enhance motion perception to the viewer and reduce flicker by making use of the phi phenomenon effect.

As a result, compared to non-interlaced footage (for frame rates equal to field rates), interlaced video doubles the time resolution (also known as temporal resolution). At the same time, interlaced video has a lot of requirements which need to be satisfied in order to make it function well. A display capable of showing the individual fields in a sequential order is necessary for interlaced signals. As a result, considering the electronic scanning and apparent fixed-resolution, there are only two kinds of displays are able to display interlaced signals: CRT displays and ALiS plasma displays.

Interlaced scan, along with progressive scan, is one of the two common methods for “painting” a video image on the electronic display screen which is realized by scanning or displaying each line or row of pixels. Under such condition, two fields are utilized to create a frame by this technique. One field contains all odd lines in the image, while the other contains all even lines.

For example, a PAL-based television set display scans 50 fields every second (25 odd and 25 even). A full frame, every 1/25 of a second (or 25 frames per second), is created by the two sets of 25 fields working together. At the same time, a new half frame every 1/50 of a second (or 50 fields per second) is created with interlacing. On the other hand, deinterlacing is applied to the video signal in order to display interlaced video on progressive scan displays in the process of playback. 

Tuesday, January 20, 2015

Different Types of Computer Cases

Traditionally, there are two basic styles when it comes to computer cases: the desktop and the tower. Desktop computer cases are flat and box-shaped. Its height is about eight inches (20 cm). From its given name we can know that the desktop computer case is designed to sit on top of the desk. The majority of desktop computer case users often place their monitors on the top of the case with the intention of saving space. On the other hand, tower computer cases are tall, deep and narrow for they are tipped up on one side. Generally speaking, tower computer cases are placed below the desk.

Users can open the desktop computer case by lifting the top off. The motherboard of the computer is installed on the bottom of the computer while the hard drive is installed in bays. One or more DVD/CD players, a floppy drive, advanced sound card interface and any kind of device made for a computer bay can be accommodated in the front of the desktop computer case at the same time. Although some computer cases feature connectivity for front USB, Firewire, microphone and headphone ports, the majority of the port lies at the rear of the case.

People design the tower computer case with the intention of saving space. The tower computer case are usually placed on the floor by the feet or to the right in a cubbyhole present on some modern computer desks in order to accomplish its mission, which can bring users much convenience and benefits. In addition, there are several ways for users to make use of when opening the tower case according to the model. Sliding away one or both sides and lifting away the top together with both sides are both feasible and useful.

It is very beneficial for users to master a good knowledge of the computer case for they can choose a model they will take most advantages of.

Monday, January 19, 2015

A Brief Introduction of Computer Cases

A computer case is also known as a computer chassis, tower, system unit, cabinet, base unit or simply case. Sometimes, people may call it the “CPU” or “hard drive”, which is totally wrong. A computer case holds the components that make up the computer system, usually excluding the monitor, mouse and keyboard for they are separate. Generally speaking, computer cases are made from steel (often SECC — Steel, electrogalvanized, cold-rolled, coil) or aluminum. Plastic is also used by the manufacturer from time to time. On the other hand, some common material may be adopted by people when making home-built cases. For example, glass, wood and even Lego blocks may be taken use of by people. Another thing people are supposed to pay attention to is that a computer case can come in various sizes and models according to the requirements of the user and many other important factors. Therefore, people will have many choices to make in order to have a better experience in terms of computing and enjoy more convenience, which can bring them a lot of benefits.

As we all know, a computer case has a variety of sizes (known as form factors). There is no doubt that the motherboard is the largest component of the majority of computers, so the motherboard plays a vital role in the determination of the size of the computer size. As a result, the size and shape of a computer case is different from each other because the form factor of the motherboard is various from each other. In addition, the form factor of the personal computer typically specifies only the internal dimensions and layout of the case. Meanwhile, the form factor for rack-mounted and blade servers may include precise external dimensions at the same time for these kinds of cases must themselves well fit in specific enclosures.

Sunday, January 18, 2015

Suggestions on Firmware

Generally speaking, firmware is at the heart of almost all popular digital devices. It is safe to say that everywhere we can see digital device that uses the firmware, for example, portable audio players, cell phones, personal digital assistants, digital cameras and gaming consoles. In electronic systems and computing, firmware is the combination of persistent memory and program code and data stored in it. The firmware contained in the above-mentioned devices provides the control program for the device. 

On the other hand, it may be very difficult for users to change the firmware of a device during its economic lifetime. There are some problems people have to deal with when upgrading the firmware. There is some firmware memory devices permanently installed, which means that people are not able to change them after manufacture. However, users always have to fix bugs or add features to the device, which demands them to upgrade the firmware. As a result, users have no choice but to replace the ROM integrated circuit or reprogram the flash memory through a specially designed procedure. 

Therefore, users should buy the electronic items that can be upgradable. Keep in mind that the product is usually advertised as being “upgradable” when shopping for electronic items. With such device, users are capable of upgrading the firmware online by connecting the device to the manufacturer’s website or a universal serial bus or FireWire port on a computer system and following the instructions given by the manufacturer. 

The firmware being upgradable can extend the life of the electronic device as well as add new functionality. However, what can not be ignored is that flashing the chips can be risky at the same time as the device will not boot when the flashing process is interrupted or become corrupted. Therefore, users cannot be more careful when upgrading the firmware when following the instructions given by the manufacturer. Besides, it is advisable to back up the important data in advance.