Analysis
Hey, what's wrong with this DVD?
Playback quality depends on encoding, the caliber of disc and how much information is stored.
By Bob Skidmore, Special to the Times Published July 30, 2007
How many times have you attempted to play a DVD only to have it rejected, pixilate, skip or freeze? You can blame a lot of different factors and the lack of a single standard.
Let's start with the various DVD formats and standards:
DVD REPLICATED: This is a DVD that is stamped as opposed to being burned. It's generally used in high-volume duplication, such as the feature films you find in your local video store. In theory, replicated DVDs should play in most DVD players with little or no problem. But not long ago, I bought three major studios' DVDs, and two of the three were rejected by my name-brand player. The LCD readout indicated that they were blank, but when I tried another player, they worked fine. This is simply the nature of a technology that I like to refer to as A Work In Progress.
BURNED DISCS: DVD-R is the most popular and is used for video and data recording. It is also available in a camcorder version that stores 1.4 gigabytes, 30 minutes or 500 still images, and is smaller so it can easily fit in a palm-size camcorder. DVD+R also is used for data and video recording, but it is far less popular. Both of these formats are available in a RW version, which means that they can be erased and recorded up to 1,000 times. DVD-RAM is a less popular variety, and can store 2.8GB, 60 minutes or 1,000 still images. It is available in a RW version, which can be erased and rerecorded up to 100,000 times.
Well, you have your player, but some of your discs have problems playing back. What causes that?
ENCODING: Many different computer programs encode DVDs, and no two are alike. Therefore, the manufacturer of the player must incorporate these differences into their reading software. If they don't, you could have a problem. Rapid scene changes and transitions can cause drastic data-rate fluctuations, which can affect a clean playback.
COMPRESSION: Compression removes redundancies, or repetitions, in digital media to reduce the amount of recorded information so it can fit on a disc. The more you try to fit on a disc, the more compression is required and the greater chance of reproduction defects and compatibility problems with various players. A burned disc compressed for two hours or less has the best compatibility about 85 percent, while a disc that has six hours of recorded material has about a 40 percent compatibility factor.
MEDIA: No-name brand DVDs may be inexpensive, but they can contribute to playback problems. Generally, such discs have poor surface consistency, which may result in a lack of information being recorded. Also, they tend to chip easily, which will contaminate the disc and recorded material will be lost over time. Branded DVDs, such as Maxell, Sony, FUJI, Taiyo Yuden and TDK, may last a lifetime and are worth the investment.
DAMAGE: Scratches, dust, fingerprints and prolonged exposure to light may affect recorded material. Keeping DVDs in a hot environment can cause warping. I like to store my DVDs in a dark- colored case, in an upright position in a cool place. Avoid affixing labels unless you have a very good device, like CD Stomper, that properly centers them. Some DVDs have printable surfaces, and are usually identified with a "P" in the part number. They require a printer such as the Epson 960 to allow printing on the face of the DVD. But at no time should you imprint on the recorded side of the disc.
Hey, what's wrong with this DVD?
Playback quality depends on encoding, the caliber of disc and how much information is stored.
By Bob Skidmore, Special to the Times Published July 30, 2007
How many times have you attempted to play a DVD only to have it rejected, pixilate, skip or freeze? You can blame a lot of different factors and the lack of a single standard.
Let's start with the various DVD formats and standards:
DVD REPLICATED: This is a DVD that is stamped as opposed to being burned. It's generally used in high-volume duplication, such as the feature films you find in your local video store. In theory, replicated DVDs should play in most DVD players with little or no problem. But not long ago, I bought three major studios' DVDs, and two of the three were rejected by my name-brand player. The LCD readout indicated that they were blank, but when I tried another player, they worked fine. This is simply the nature of a technology that I like to refer to as A Work In Progress.
BURNED DISCS: DVD-R is the most popular and is used for video and data recording. It is also available in a camcorder version that stores 1.4 gigabytes, 30 minutes or 500 still images, and is smaller so it can easily fit in a palm-size camcorder. DVD+R also is used for data and video recording, but it is far less popular. Both of these formats are available in a RW version, which means that they can be erased and recorded up to 1,000 times. DVD-RAM is a less popular variety, and can store 2.8GB, 60 minutes or 1,000 still images. It is available in a RW version, which can be erased and rerecorded up to 100,000 times.
Well, you have your player, but some of your discs have problems playing back. What causes that?
ENCODING: Many different computer programs encode DVDs, and no two are alike. Therefore, the manufacturer of the player must incorporate these differences into their reading software. If they don't, you could have a problem. Rapid scene changes and transitions can cause drastic data-rate fluctuations, which can affect a clean playback.
COMPRESSION: Compression removes redundancies, or repetitions, in digital media to reduce the amount of recorded information so it can fit on a disc. The more you try to fit on a disc, the more compression is required and the greater chance of reproduction defects and compatibility problems with various players. A burned disc compressed for two hours or less has the best compatibility about 85 percent, while a disc that has six hours of recorded material has about a 40 percent compatibility factor.
MEDIA: No-name brand DVDs may be inexpensive, but they can contribute to playback problems. Generally, such discs have poor surface consistency, which may result in a lack of information being recorded. Also, they tend to chip easily, which will contaminate the disc and recorded material will be lost over time. Branded DVDs, such as Maxell, Sony, FUJI, Taiyo Yuden and TDK, may last a lifetime and are worth the investment.
DAMAGE: Scratches, dust, fingerprints and prolonged exposure to light may affect recorded material. Keeping DVDs in a hot environment can cause warping. I like to store my DVDs in a dark- colored case, in an upright position in a cool place. Avoid affixing labels unless you have a very good device, like CD Stomper, that properly centers them. Some DVDs have printable surfaces, and are usually identified with a "P" in the part number. They require a printer such as the Epson 960 to allow printing on the face of the DVD. But at no time should you imprint on the recorded side of the disc.
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