VCD/DVD Basics Tutorial

VCD/DVD Basics Tutorial

Converting videotapes to VCD and judging VCD quality

Converting videotape to VCD: Converting videotape to VCD is to convert the information recorded on the videotape (analog signal) into a signal (digital signal) that can be recognized by the computer through a video capture compression card (acquisition card), and then burn it into a VCD disc through special burning software. This makes it very convenient to carry and store, and there is no need to worry about quality problems over time. It can be stored permanently, and the videotape can be reused.

How to judge the quality of personal VCD production:
1. Disc: The quality of the disc mainly depends on whether the coating of the disc is thick enough. Hold the disc up to the light and look at it. The less light is transmitted, the better the quality.
2. Listen to the sound. There must be no phenomenon of asynchrony between sound and image. The sound should be full, and the high, medium and low tones should be clear.
3. Look at the image. There should be no mosaic. Look at the brightness, color saturation and contrast of the image. The image should not have the phenomenon of "dropping frames" like watching animation. The main products of optical disc storage technology are optical discs and optical disc drives or optical disc machines. Optical discs can store a large amount of digital information, including text, images, graphics, sounds, etc. Optical disc drives or optical disc machines are used to read information and data from optical discs and write information and data to optical discs. Since optical discs have the advantages of high storage density and large capacity, and are easy to preserve for a long time, they provide a powerful carrier for the storage of multimedia information. Optical disc technology has become the main means and guarantee for the development of multimedia technology. Therefore, since the 1980s, the optical disc technology industry has launched different types of optical discs and corresponding reading and writing devices, such as compact disc audio (CD-DA), compact disc read-only (CD-ROM), compact disc interactive (CD-I), compact disc with extended structure (CD-ROM XA), compact disc writable (CD-R), video disc (V-CD), photo disc (Photo CD), etc., and is still continuing to research and develop erasable optical discs and DVD digital versatile discs, and is developing rapidly.

Generally speaking, a CD is composed of a glass layer, a reflective layer, a signal layer, and a protective layer. The signal layer is the main body of the CD, which contains many concentric circular tracks. The tracks have micro-pits and flat lands that record digital signals, where micro-pits represent "1" and flat lands represent "0". When the laser probe reads, due to the different reflection modes of the laser on the micro-pits and flat lands, the reflected information received by the CD player is different, and the digital signal can be distinguished as "1" and "0" and read. CDs can be divided by type, size, medium, or storage content, but based on the function of their read and write forms, they can basically be divided into three types: CD-ROM, CD-R WORM, and CD-RW.

The CD-ROM is the earliest CD to enter the market and has the most mature technology. The data stored in it is pre-written, and users can quickly retrieve and read the signal data through the CD-ROM drive, but they cannot write their own content to the CD-ROM. Most of the 7 types of CDs mentioned above are read-only CDs, such as audio CDs, which store digital audio signals; interactive CDs store text, images, sounds, computer programs and data in large-capacity read-only CDs, and connect to TVs, computers, mice, joysticks, etc. through the CD-I real-time operating system of the CD player to achieve the interaction between users and programs, so they can be used for computer-assisted teaching or home multimedia entertainment; structure expansion CDs are a combination of read-only CDs and interactive CDs. Users can choose 3 levels of sound: laser disc data audio, FM, and voice. These sounds can be combined with the moving images on the screen; video CDs use MPEG standard compression encoding technology to store images and accompanying sounds in full digitization. The image quality is better than that of videotapes, so various video programs can be recorded for home theater viewing.

Read-only CDs are easy to copy, have low manufacturing costs in large quantities, and have large storage capacity. Currently, a large amount of literature, educational programs, film and television works, computer software, electronic games, reference books, etc. are produced and distributed via read-only CDs.

Previously, due to the lack of logical file structure and index format standards, CD-ROMs were incompatible with each other, which affected their widespread application. Now, due to the use of common logical files, the compatibility problem has been solved. CD-ROM drives can support the various CD-ROM formats and photo CD formats mentioned above, becoming one of the standard configurations of MPC multimedia computers. In addition, CD-ROM drives have been developing towards high speed, from the single speed (150KB/S) at the time of birth to 8 times the speed, although the MPC3 standard is 4 times (600KB/S). Last year, 12 times the speed of the product entered the market.

According to statistics, the total installed base of CD-ROM drives in the world has exceeded 100 million units, and read-only CDs accounted for 90% of CD sales in 1996.

A write-once optical disc allows the user to write data once. After writing, the information recorded on the disc cannot be rewritten, but it can be written in segments until it is full (the aforementioned photo disc is one of them). A write-once optical disc can be read repeatedly in a CD-ROM drive or a write-once optical disc drive like a read-only optical disc. It is fully compatible with read-only optical discs. Write-once optical discs can be accessed randomly, and the stored information is stable and reliable, with a long life. They are mainly used for storing large amounts of data that do not need to be changed frequently and are not distributed in large quantities.

At present, we need to rely on the burning software provided by CD-R manufacturers in DOS and WINDOWS environments to use CD-R drives to read and write write-once optical discs. Therefore, the International Standardized Optical Storage Technology Association has developed the CD-UDF universal disk format. As long as the corresponding device driver software or extension software is developed for each operating system, the operating system can see the CD-R drive as a logical drive. In the future, users can write to CD-R in DOS or WINDOWS, just as conveniently as using floppy disks and hard disks.

Rewritable optical discs mainly include magneto-optical discs and phase-change discs. The former read-only discs use the result of the combined action of lasers and magnetism to record digital information, while the latter only uses optical technology to record and read information. It records and erases information based on the reversible phase change structure of the recording medium between the crystalline state and the amorphous state caused by the laser. Neither magneto-optical discs nor phase-change discs can be read by ordinary read-only optical disc drives, but the reading method of phase-change discs is the same as that of CD-R and CD-ROM discs, so it is relatively easy to realize a multifunctional phase-change optical disc drive that is compatible with CD-R and CD-ROM. Last October, five companies including Philips and Sony jointly launched a new rewritable optical disc standard, named this disc CD-RW, and began to develop new products for the market. It is compatible with read-only discs and write-once discs, and its drive allows users to read three different forms of discs, burn write-once discs, and rewrite rewritable discs. It is expected that this product will be available in 1997.

In the development of optical disc technology and among the numerous optical disc technology products, CD-ROM and its driver are undoubtedly the biggest winners. In the future, write-once and rewritable optical disc products will have a good development as they solve the compatibility and interchangeability with read-only optical disc products and other technical problems. In addition, DVD products, which are much better than read-only optical discs in capacity and interactivity and compatible with read-only optical discs, are expected to replace many read-only optical disc products in a relatively short period of time.
Whether you go to computer stores or information exhibitions, you can almost always see three Video CDs for 500 yuan. Stacks of VCDs seem to be sold by weight. The MPEG1 and Video CD that were once hotly discussed have fallen to this level. If your computer has an MPEG card installed, you might as well take advantage of this opportunity to get a bargain. If you don't have an MPEG card, I believe no one will recommend you to buy a Video CD Player. People will definitely say, wait and watch DVD!
In the past two years, whether it is the computer, audio and home theater industry, people always keep hearing people mention DVDs, but they always hear the sound of stairs, but never see DVDs. Now it has finally appeared, not only in various electronic products or audio equipment, but also on the market, and it has immediately become the focus of attention from all walks of life. What exactly is DVD, and do you need to buy a DVD player?

什么是DVD？
DVD的全名原本是 Digital Video Disk，即数位视讯光碟或数位影碟，是利用 MPEG2的压缩技术来储存影像，希望以更小的体积、更大的储存容量，取代12寸的LD影碟，有点像是使用 MPEG1的Vedio CD的进级产品。然而看中 DVD大储存量的电脑界和觊觎它高传真的数位声音的音乐界，对DVD亦同样寄予厚望，於是有人又称DVD是Digital Versatile Disk，是数位多用途的光碟，它的用途之广，可以从已设定的五种规格用途看出，包括∶
Book A的DVD-ROM是电脑资料档唯读光碟，用途类似CD-ROM；
Book B的DVD-Video是家用的影音光碟，用途类似LD或Video CD；
Book C的DVD-Audio是音乐碟片，用途类似音乐CD；
Book D的DVD-R（或称 DVD-Write-Once)是限录一次的DVD，用途类似CD-R；
Book E的DVD-RAM(或称 DVD-Rewritable)是可多次读写的光碟，用途类似MO。
从它的多用途（注1）， 你可以想见何以它所涉及的产业之广，总是为人关注的原因了。一张光碟能够具多种用途，现有的CD(Compact Disk)虽然也可以做到，但DVD的储存空间和高品质的音质，现有的CD却难项其背。DVD优於CD的特色，可以从几个方面说明∶

1.大容量和快速读取∶大多DVD与一般CD的大小相同，直径约 12公分（也有8公分的），由二个厚度各为0.6mm的基质层黏贴而成，采用多面多层的技术，即每一面光碟可以储存双层资讯，一张光碟最多可四面的储存空间，DVD 利用聚焦更集中的红光雷射提高了每单位面积的储存密度，因此可说其储存空间是空前的大，表一便将各种不同储存形式的储存容量和适用规格做一整理。此外，利用较短波长的雷射和较密集的讯坑制作，可以使单层 DVD的最大读取率达11.08 Mbit/sec，相当於八倍速的光碟机。

2. High-resolution video: DVDs that use MPEG2 standard image compression technology can achieve a resolution of 720x480, far exceeding the 352x240 of VCDs. In addition, MPEG2 has the ability to flexibly adjust the video reading rate, so it can save a lot of video storage space while maintaining the original image quality. In addition, the built-in Letterbox and Pan and Scan display modes of DVD players can also adjust the aspect ratio of 16:9 or 4:3 TV screens.

3. High-fidelity sound quality: DVD can use more precise sampling accuracy to convert analog signals and expand the traditional two-channel to 5.1 channels, allowing people to enter the world of multi-channel.

Market Analysis of DVD+/DVD-R Recording Formats

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If you want to buy a DVD recorder, you will find that there are two camps in the DVD recorder market: DVD+R, DVD+RW (collectively referred to as DVD+) and DVD-R, DVD-RW (collectively referred to as DVD-). DVD+ and DVD- have been competing against each other in the DVD market and have become the focus of discussion. Both DVD+ and DVD- are DVD recording formats. DVD+R and DVD-R can only be used for one-time recording, while DVD+RW and DVD-RW can read and write to the recording medium many times, usually about 1,000 times. The two recording methods of DVD+ and DVD- are basically incompatible with each other. They have their own supporters and their own technical advantages. In this article, we will understand these two different DVD recording formats from the user's point of view and help users choose a DVD recorder that suits them. At the beginning of this year, at the DVD Technology Conference, Ms. Harpe from the DVD+ camp, Philips, and Chairman Yoshimura from the DVD- camp, Pioneer, respectively expressed their positions and views. Why are there two formats? In the CD industry, there is only one unified recording format for rewritable CDs, while in the DVD industry, many companies do not agree on a single DVD recording format, which has resulted in two major camps: DVD+ and DVD-. As DVD technology continues to advance, the situation in these two camps has become increasingly chaotic, with supporters of DVD+ and DVD- being equally strong, with neither able to convince the other. As major players in the optical media industry, Korean and Taiwanese companies have indicated that they will not stick to a single DVD recording format, but will pursue a two-pronged approach based on market trends.

In the development process of DVD recording media, DVD+ was mainly proposed and developed by Philips, HP and Dell, while DVD- was researched and promoted by Pioneer, Toshiba and Apple. Both parties are very strong, which is also the main reason for the current chaos in the DVD recording media market.

Will a war break out?
Many comments describe the two DVD recording formats as a war, but I personally think that the word "competition" is more appropriate. DVD+ and DVD-, who will be the final winner, is still undecided. In the past, in terms of video recording formats, BetaMax and VHS also had such a confrontation. The two formats were incompatible with each other, and consumers could only wait and see. Although the DVD+ and DVD- formats are different, they are still compatible with each other in most technologies. Therefore, DVD recorders that support both DVD+ and DVD- formats have appeared on the market. Of course, the price of such recorders is also quite high, and most users are currently taking a wait-and-see attitude.

Which format is more important for DVD recorders?
Consumers always want to get high-performance products at the lowest price, so when buying a DVD recorder, most users have to think over and over again. One of the most important issues is the compatibility of the two formats. If a certain DVD disc cannot be used in another DVD recorder, this is the situation that users are most reluctant to see. DVD+ and DVD- exist in this problem, but in essence, DVD+ and DVD- still have quite a lot in common, so when users choose a DVD recorder, there is such a situation: the more compatible formats a DVD is, the more expensive it is.

In most current DVD recorders, 90% of the DVD-R and DVD+R formats are compatible. However, there is only a 70% chance that DVD-RW and DVD+RW are compatible. Even if a certain DVD recorder can be compatible with two different formats, it is rare to buy discs that are compatible with both DVD formats. DVD recordable discs often perform better in one format depending on the different recorders.

Price factor?
Therefore, from the current point of view, the price factor has become the main indicator of DVD recorder performance. The higher the price, the more DVD disc formats the DVD recorder can be compatible with. DVD+ has more functions, so it takes the initiative in market strategy and promotes the recording format of DVD+ in various fields; while DVD- is mainly defensive in market strategy, but the scope of defense is also quite wide. Once DVD+ enters a field, DVD- will follow immediately. In the current market, DVD+ and DVD- each account for 50% of the market, but DVD- entered the market earlier than DVD+.

Another factor that caused the current chaos is the optical media market in South Korea and Taiwan. They are the largest users of optical media, but they have not made a clear statement of their own position, but have taken all the advantages. For example, large companies such as LG, Lite-On, Samsung, and Benq have launched DVD recorders that support both formats. The price of each recorder is between 1,000 yuan and 1,200 yuan, and the price of DVD discs that support both formats is also quite high.

Although Microsoft supports the DVD+ format, it is not up to it alone. Both DVD+ and DVD- have their own advantages and reasons for existence.

Market decision
If we give a purchase recommendation, we will also recommend both, just like Korean and Taiwanese companies, but the price of this choice is not affordable for every user. At present, there is an important point that DVD+ is supported by two major companies, Dell and HP. They are two giants in the PC manufacturing industry. Their various products have a very high market share. They have enough strength and market to promote the DVD+ format. HP has already configured DVD+ burning devices in the PCs it launched. Dell is also preparing to take this measure in the near future to add DVD+ burners to PC configurations.

The final result of their actions will be that the price of DVD+ burners will plummet. Once the price of DVD+ drops to a range acceptable to users, DVD+ will be immediately recognized by the market and accepted by users, becoming the winner of the competition. Therefore, personally, I will choose DVD+ burning equipment.

Does this mean that DVD- will fail in the market? This is not the case. DVD- is not inferior to DVD+ in performance. DVD- entered the market earlier than DVD+, so it has a large customer base. If DVD- devices can increase their speed (Pioneer's fastest DVD burning speed is 16X), they will have stronger competitive strength.

Conclusion
Although there are DVDs that support both formats on the market, after considering the price and performance factors, we think that users should choose a DVD burner that only supports one format. Based on the above analysis, we think DVD+ is a more reasonable choice, but if you have enough money, you might as well choose a DVD burner that supports both formats.