Help DVD Recording SP, EP, SLP Setting Question [Archive] - Audio & Video Forums

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hershon
11-26-2004, 02:50 PM
Let me preface this question, that when I recorded on my VCR, I never noticed a significant difference in picture for my taste at SP, EP & SLP recordings. Now that I've bought my DVD Stand Alone Recorder and started taping TV shows via Time Warner Digital box, I noticed that while the picture is fine at SP, if I record TV shows at SLP (the slowest speed), I get light yet slightly visible type lines in the picture. Is this what I can expect if I record TV at SLP? If I was recording from VHS to DVD on it at SLP, would these lines still show up as well? Thanks

Lensman
11-26-2004, 10:00 PM
Let me preface this question, that when I recorded on my VCR, I never noticed a significant difference in picture for my taste at SP, EP & SLP recordings. Now that I've bought my DVD Stand Alone Recorder and started taping TV shows via Time Warner Digital box, I noticed that while the picture is fine at SP, if I record TV shows at SLP (the slowest speed), I get light yet slightly visible type lines in the picture. Is this what I can expect if I record TV at SLP? If I was recording from VHS to DVD on it at SLP, would these lines still show up as well? Thanks

What you're seeing is called "artifacting," a term referring to anything that's not supposed to be in the picture. DVD video is encoded by a recording process (typically MPEG-2) that uses lossy compression (information gets thrown away) to remove redundant information, such as areas of the picture that don't change, and information that's not considered readily perceptible to the human eye. All DVD video, including new studio releases you buy are compressed.

The more you record on a disk, the more compression is required, so the more artifacts will appear. It doesn't matter whether the recording is from TV, a videotape, or anything else. Artifacts are most noticable in fast moving or complex scenes. The look takes a bit of getting used to. When you recorded something with a VCR at different speeds, the entire picture would gradually get worse, so the degradation wasn't so noticeable. But with digital recording, much of the picture stays razor sharp, but various flaws such as color banding, blurriness, blockiness, fuzzy dots, shimmering, the lines you're seeing, etc. begin to manifest themselves in different places.

DVD+Rs like you use are designed to hold about 133 minutes of video. Anything beyond this amount starts introducing noticeable artifacting. Studios get around this limitation by using higher capacity disks such as dual layer DVDs that can hold 233 or 266 minutes (which is why you have to use something like DVDShrink to back one up).

hershon
11-26-2004, 10:26 PM
Thanks for the info which is really helpful to me. Would you mind answering a couple of other related questions: 1, If I use a rerecordable DVD+RW disc, will the amount of times I use this disc affect the picture quality? What I have been doing is fully erasing the disc before I start recording it over again. 2. Is it my imagination but it seems like when I record from VHS to DVD+R(W) on my standalone recorder and then make a "clone" DVD via my computer using DVD Shrink, it seems like my "clone" is better quality than the first original. Is there a reason for this or is my mind playing tricks on me. If it is my imagination, will I get the same quality clone if I just make a direct copy with Nero software on my computer or if I do this via DVD Shrink and Nero? Thanks



What you're seeing is called "artifacting," a term referring to anything that's not supposed to be in the picture. DVD video is encoded by a recording process (typically MPEG-2) that uses lossy compression (information gets thrown away) to remove redundant information, such as areas of the picture that don't change, and information that's not considered readily perceptible to the human eye. All DVD video, including new studio releases you buy are compressed.

The more you record on a disk, the more compression is required, so the more artifacts will appear. It doesn't matter whether the recording is from TV, a videotape, or anything else. Artifacts are most noticable in fast moving or complex scenes. The look takes a bit of getting used to. When you recorded something with a VCR at different speeds, the entire picture would gradually get worse, so the degradation wasn't so noticeable. But with digital recording, much of the picture stays razor sharp, but various flaws such as color banding, blurriness, blockiness, fuzzy dots, shimmering, the lines you're seeing, etc. begin to manifest themselves in different places.

DVD+Rs like you use are designed to hold about 133 minutes of video. Anything beyond this amount starts introducing noticeable artifacting. Studios get around this limitation by using higher capacity disks such as dual layer DVDs that can hold 233 or 266 minutes (which is why you have to use something like DVDShrink to back one up).

Lensman
11-27-2004, 08:05 AM
Thanks for the info which is really helpful to me. Would you mind answering a couple of other related questions: 1, If I use a rerecordable DVD+RW disc, will the amount of times I use this disc affect the picture quality? What I have been doing is fully erasing the disc before I start recording it over again. 2. Is it my imagination but it seems like when I record from VHS to DVD+R(W) on my standalone recorder and then make a "clone" DVD via my computer using DVD Shrink, it seems like my "clone" is better quality than the first original. Is there a reason for this or is my mind playing tricks on me. If it is my imagination, will I get the same quality clone if I just make a direct copy with Nero software on my computer or if I do this via DVD Shrink and Nero? Thanks

I don't mind at all:

1. No. As long as the disc material is capable of recording the signal written to it, there's no degradation from rerecording. Reusing (and playing) videotape erodes the magnetic coating from contact with the rollers and heads in the VCR, gradually degrading picture quality. DVDs use lasers to make and erase pit marks on the disc surface that's sandwiched between the layers of protective clear plastic. Rewritable DVDs work perfectly until the media can no longer take the laser marks, then they stop working. DVD+RWs are rated at 1,000 rewrites. Their storage life is rated between 30-100 years (though it can be significantly less for cheap discs). This compares with videotape's life of 15-20 years.

2. I'm not sure. DVD Shrink does use its own compression algorithms. So in theory the picture should, if anything since you're not actually needing to compress, look a little worse because you're losing some data. But the compression routine could be doing something that makes things look a little better to you. In theory a direct copy with Nero would be better.