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06-26-2010, 11:23 PM
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You mentioned a tft scan or something after burning - would the best way be to run verify scan after burning with imgburn?

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06-27-2010, 05:27 PM
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TFT scan was a typo. It should have read TRT scan instead.

TRT = transfer rate test
It's a test of whether or not a disc can be read by the drive its in.

Use Nero Disc Speed for testing and scanning DVDs, available here. This is the last freeware version of the program. They now charge for the next evolution of that program, Opti Drive Control. (If you do a lot of disc testing, and results matter, it's worth the $25)

This is what the TRT looks like:


This exact image is of a good scan or a DVD+R DL (MKM001 Mitsubishi-manufactured Verbatim-branded disc). Note the increase up for one layer, and the decrease down for the other. Bad discs will generally form valleys in the middle, and/or the second layer will be a mess. I don't have a bad DVD+R DL on hand right now to demonstrate.

These scans won't be fast (10-20 minutes), and you should not use your computer during that time -- not if you want reliable results.

For the most useful results, I would suggest that you need to use a different DVD burner drive than the one it was burned in -- if available.

Some would suggest that for the most accurate results, you need to use the same drive that the disc was burned in. However, I find that a silly notion. If the only drive that can successfully read the disc is the one that burned it, what good is the burned disc? True, the drive can tell if the disc is readable at all -- but that's really not as important as the general playability of the disc. How many people watch DVDs at their DVD burner? (Not many.)

Ironically, it's these same people (the "accuracy" crowd) that would also suggest it's okay to use your computer while the test is ongoing. That's just going to make the results more skewed.

Testing it twice may be the best solution, when doing archiving -- once in the burner drive that made it, and once in another drive. This way you don't subject yourself to too much DVD drive bias, and you can tell both if the burn was good (on the burner drive), as well as if the burn is readable in general (on the other drive). This assumes you know both drives are in good condition, and don't have bias against any media types/IDs. For example, I have a BTC drive that hates Taiyo Yuden DVD-R media, be it for burning or reading. The drive is no good for any TY DVD-R use whatsoever.


None of the "verify" options found in any program are reliable -- be it Nero, ImgBurn, DVD Decrypter or others. The one in Nero plain sucks, and always has. I think it gives false results more often than not.

The verify functions in ImgBurn and DVD Decrypter (as written by the programmer known as LightningUK!) are better than Nero, but still known to give off false negatives and false positives. In other words, the verify passes when it should fail, or it would fail when there's nothing wrong with the burn (or data that was burned).

LightningUK! has insisted it works correctly, and I don't doubt he's tested it thoroughly on the drives/discs he has available, but there's many instances where it's been proven to give out false data, as per user reports in forums (and from reliable/knowledgeable people, not know-nothing yahoos).

So I'd just skip a verify, it's a waste of time. You're better off with TRT and a scan disc.

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Last edited by lordsmurf; 06-27-2010 at 05:33 PM.
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06-27-2010, 06:29 PM
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thanks for the info
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06-27-2010, 07:06 PM
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This might be more information than you need, but here's some added scanning of this same disc. What I want to address here is the fact that fancy numbers/statistics tests (PIE/PIE testing) don't necessarily tell you anything more valuable than the simple graphics-based tests (TRT + scandisc).


General Information
 Drive: BENQ    DVD DD DW1620   
 Firmware: B7T9
 Disc: DVD+R DL (MKM 001)
 Selected speed: 8 X
PI errors
 Maximum: 45
 Average: 11.28
 Total: 360301
PI failures
 Maximum: 8
 Average: 0.01
 Total: 2375
PO failures: 0
 Maximum: 10.4 %
 Average: 8.06 %
Scanning Statistics
 Elapsed time: 18:29
 Number of samples: 31942
 Average scanning interval: 8.00 ECC
 Glitches removed: 0
A 4x scan was almost identical in results.

This is the type of scanning many self-described "CD/DVD freaks" like to do. Honestly, it's not a whole lot more useful than a TRT or surface test (scan disc). All of these tests essentially answer the question, "Can this disc be read without problems?" But each test does it in a different way.

You also have to remember that the drive in use can highly bias the scan results. This drive used here, a BenQ 1620, was at one time the preferred drive of the "freaks" crowd. It's now fallen out of favor. (These people change their minds about scanning techniques as often as most people change their underwear. It's hard to keep up.)

This scan doesn't really tell me anything different than the TRT, in a general sense. That is, that this disc is good.

All of the values are within norms, and there shouldn't be any playback or reading errors when the is played or read. Jitter is good, PI failures are good, PI errors are okay.

I've seen some better results. I've seen many worse results.

If I scanned this disc again, the results would be different by a slight amount. Right now it's very humid outside (and thus increased humidity inside) due to summer rains. If I scan this disc again in a week, environmental conditions will have altered the scan results. Same for scanning it this fall, this winter, next spring. This disc would still be good, but the %'s and numbers would change. The aging of the drive would also have some affects, as would any damage to the disc (including microscopic damaged caused by handling and storage). Sadly, many people would take this to mean the disc has "died" or "degraded" or some other such mythical nonsense.

If I scanned the disc on another drive entirely, the percentage/numbers results would be different. But the TRT and scan disc would generally remain the same. Hence, those tests are generally more useful.

So just in case you were curious.

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06-27-2010, 09:50 PM
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Similar discussions here:
I like this quote:
In years past many of us have often wondered if the introduction of error scanning was a mistake. There's far more "wrong" applications of this stuff than "right". I'll wager that 90% of the folks doing it have no idea what they're measuring or what it really means. For those 90%, a plain old transfer rate or scandisc test is probably more appropriate.

There's really only one legitimate use for scans, and that is to compare disc A to disc B, both of which are burned in the same drive with the only difference being the burn speed or the media type. Any other use of a scan is suspect, and probably mis-guided. With the above stated purpose, it really doesn't matter what the scanning drive is reporting, or how, only that it does so consistantly. In other words, the actual error levels or counts are NOT the main point. That disc B is "better than" disc A is the main point.

Use of error counts and averages for some sort of "benchmark" of relative burn quality is totally unsupported in the DVD specs. It can be used within the above stated example, but again only to compare disc A to disc B. And often even then it will be misleading. The exception might be where you are scanning only a set small range of blocks and comparing total counts. But this gets too technical, and far beyond the range of what the average end user would be doing.
That's basically it.

Funny how that was said more than 4 years ago, but the addiction to scans seems to persist in certain online communities.

... although I'd add that it's still more a measure of the drive's ability to read than the disc itself. You can't really use tests like these, by themselves, as the basis for statements about how different discs compare against one another (i.e., CMC vs Taiyo Yuden). All you can tell is how that particular drive interacts with that exact disc. In mass quantity, you can compare the manufacturers, but you're still isolated to that one drive (and on that one firmware). You have to burn exponentially more discs, on many drives/firmwares, and test them with multiple methods (not just PIE/PIF scanning), to have the kinds of broader conclusions people generally want to associate with single-sample or small-sample scanning. We're talking tens of thousands of discs. And for the record, that's what we've been doing here at The Digital FAQ for going on 10 years now.

That thread (where the above quote is from) turns into a bit of a pissing contest, arguing over semantics, drive choices and scanning softwares. And that's honestly how things have been for 5+ years now -- arguing over what's "best" or what's "accurate" without any acknowledgment that none of the methods are reliable (and therefore nothing can be "best"). That's the typical environment for people who overly value disc scanning in small samples.


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