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:
trt-scan-dvdplusDL.jpg
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.
Verify...
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.