Testing dvd quality not worth time

vbimport

#1

I found this site and got wrapped up in scanning dvd’s I burn for quality. I gotta be honest and say I feel it’s a complete waste of time. Using the nec 3520 burner, good verbatim and taiyo yuden media, and various firmware, I’ve been scanning burned dvd’s for the last two days try to find the best speed, firmware, media combination. No matter what combo I used, I never got the ultra low error count every one is claiming to have. So I decided to take a new approach. I took the worst dvd I’ve burned according to Nero’s cd-dvd speed 4.0 and watched the worst chapter which had a PIF of 100!. I played it on a Playstation 2, Pioneer dvd player, and Initial portable dvd player. The chapter played flawlessly on all three players. This leads me to the conclusion that scanning for quality is a waste of time other than to check out how good obscure media is. Dvd players are capable of handling almost all errors without a problem even PIF’s of 100.


#2

Keep in mind that the 3520A is a pretty good quality burner.
Disc quality scanning can be more useful for people that use low quality media and/or have a burner with questionable writing quality.
You are using good stuff. :slight_smile: ( Verbatim, TY, NEC 3520A )


#3

@maxxjulie

You are creating a lot of threads that basically discuss the same subject.

Most DVD burners sold today can burn at 8x speeds to certain types of popular DVD media. CDFreaks frontpage has a poll and the result is clearly saying Taiyo Yuden is what the voting CDFreaks visitors like most. Before K-Probe was released to the public, people who used only good quality media from Ricoh, Mitsubishi, Philips, Sony, Pioneer, TDK, and some others hardly worried about writing quality.

Most people post scan images for fun and to share their experiences, not necessarily because they are concerned too much about whether those scanned disks won’t be readable in certain DVD players.


#4

maxxjulie,

dvd scanning with consumer hardware is not useless, but it is HARD WORK when done properly.

  • First of all, scans with one single drive only tell about read error rates with that drive

  • Second, not all drives are useful for scanning to begin with (because they report inconsistently or have some other issues)

  • Third, one needs to scan with multiple drives and set limits of readability using playback testing

  • Fourth, testing a problematic burn of a DVD VIDEO disc using a dvd player (by viewing at the video material) is NOT a good way to see if the dvd player coped with the errors or not. MPEG-2 compression allows for a loss of great deal of information, before it is visible in the video stream. Testing should always be performed as bit accuracy / readability test (stochastic).

  • Fifth, scanning with a pet-darling drive like LiteOn (esp. 16xx series) can give a very misleading picture of the compatibility of the disc in other drives, because LiteOn would probably read a dvd disc even if it was pressed on camel dung. They are just so good readers. The same applies to a lesser degree to PX-716.

  • Sixth, one needs to understand the limits of what kind of conclusions can be drawn from the test data. Simplified conclusions like “PIE<280 in LiteOn => dvd burn within specifications” are not only inaccurate as reasoning (due to misunderstanding the facts), but can also lead to misleading conclusions about dvd compatibility. Do note the word can which is not the same as will.

As an example of how hard scanning work can be, I’ve just scanned c. 300 scans out of 40+ discs burned by five burners (using 8 different disc types), using seven different scanners.

The reported error rate averages and variances tell a very revealing picture of the burn quality and compatibility of the discs in a variety of devices.

However, this test has taken me over 5 weeks of continuous work to accomplish.

So, like I said, dvd scanning is HARD WORK if you want it to be accurate and useful.

Then again, if you have found out that your burners with the disc types you are using play very well on your dvd players, then be happy!

No need for you to spend long times scanning dvds.

But it does not dvd scanning useless make.

regards,
halcyon


#5

Halcyon doesn’t belong to those who “post scan images for fun and to share their experiences” but to those who try to test and gather information organized and systematized well. :bigsmile:


#6

Halcyon, you said that “not all drives are useful for scanning to begin with (because they report inconsistently or have some other issues)”. Everybody says Pioneer 109 is one of those drives, and I start to agree :-), but I would like to know why. How is it possible for a DVD drive to give such innacurate results ? What is the mechanism that generates them ? Is the process of reading errors so different than the process of pure reading a DVD ? Can you help me with information on this topic ?


#7

Nicely said. :bow:

Wesociety, is right. When I burn TY and Verbatim on my NECs there is no point in scanning other than to do a quality check from time to time. But guess what? If I had not scanned I would not have been aware that TYG01 burns very well at 8X. Usefull information, and worth the effort.


#8

Maybe a read test/surface scan in CD-Speed is enough to detemine quality of the disc?

I have a Princo disc with PIF Max 25. It plays back just fine in my standalone and I can even rip it to my HDD. Read test/surface scan report 100% Good.

/jegus


#9

PIF of 100? Was that a nice thick 100 PIF spike, from say 3,GB to 4GB? A grand total of 100 PIF on the average? Or an aberrant 100 PIF spike, that completely invalidates the scoring method of CD-DVD speed?

There’s all sorts of PIF of 100…


#10

Ignorance is bliss. :wink:

If you don’t care whether you are getting good quality burns, but only want to know whether they can be read in a given drive, then you shouldn’t bother scanning for read errors.

If you want your discs to be readable in a year, and readable in a wide variety of drives, then scanning is for you. Or, if you simply want to try to get the best quality burns possible in your burner, just because you can, then scan.

That said, if you don’t know what you are measuring, how it’s measured and what it means, then scanning is also of limited value. But, if you can look at 2 scans and see than one has lower error rates, and if you can reproduce the lower rates with a given media at a given speed in your burner, then why wouldn’t you want to do that?

If it’s too much bother, and you are willing to accept occasional disc failures, then don’t do it.


#11

Quality’s very subjective and relative. Like US$50 sofa vs. US$5,000 sofa. To me, I prefer US$50 one. Not much difference in quality. Big difference in quantity (of money.) Many others would say it’s worth the money to buy expensive sofa and bed.

Whether it’s a big difference between PIF Max of 1 and PIF Max of 25 is to be judged individually. That’s why many people here post individual scans rather than just to post “Good” or “Bad” without any more raw data to support their conclusions.


#12

You must be looking over my shoulder. This exactly reflects why I scan. Thanks for stating it so clearly. :bow:


#13

Rdgrimes = the grandfather of all media scanning. :bigsmile:


#14

Somebody call me an old fart? :sad:


#15

No way, that post count closing in on 10,000 has nothing to do with age. Just look, you only started here a month before I did and I am only…wait, I’m an old fart. :eek:

Never Mind.


#16

I think DVD players ignore many read errors when playing movies. The effect of that is not easily observable if at all. You can
scratch a disc with a knife and it can still play fine to your eyes, at most with a hiccup here and there.

Now data discs are different. Still if the amount of errors don’t exceed the spec limit, if it’s just barely within the limit, the disc will be readable. But high error numbers indicate low disc quality, and errors can develop over time. Maybe 5 years later and 100 rounds of reading and handling later, a file may become unreadable, or readable only at very low speed.


#17

Sometimes, the standalone DVD player can be the fussiest reader of all, even though it’s reading at an “easy” 1x.

There are several ways to test a burn:

  1. Verify: Proves that the disk is, at that moment, readable in the drive that wrote it
    1a. If you hear the drive speed-hunting, or see the verify speed dipping badly, then that casts doubt upon the quality - if you know it would normally manage full speed.

  2. Transfer rate test: If full, proves the disk can be read without failure, if without slowdowns, usually indicative of a pretty good burn.
    2a. A sampled test, that steps through at 5:1 skip, does not confirm 100% readability, and may miss bad spot slowdowns.

  3. PI/PIF scan: The hardest to read, or at least to assess mid level results with.
    While you CAN sample, a sampled test is only usable as a quck way to get the overall picture, as it will miss areas that may be troublesome