Is a TRT test a valid way of testing the readability of a disc?

vbimport

#1

[EDIT] Some posts in this thread (including the first post) was copied from another thread so the validity of a TRT test on a data disc could be debated.

12x DVD+R DL burn with a modified firmware

Media RICOH JPN D01c
Firmware 1.05 (modified)

It’s interesting that Optiarc uses a CAV writing method. The burn time is also pretty good.

The disc is readable, but the modified writing strategy doesn’t really suit the media.


#2

[QUOTE=Dee-27;2016616][B]12x DVD+R DL burn with a modified firmware[/B]

Media RICOH JPN D01c
Firmware 1.05 (modified)

It’s interesting that Optiarc uses a CAV writing method. The burn time is also pretty good.

The disc is readable, but the modified writing strategy doesn’t really suit the media.[/QUOTE]How do you know it reads back with meaningless files on it? You cannot watch it…you have not read it back to your HDD…


#3

[quote=Bob;2016624]How do you know it reads back with meaningless files on it?[/quote] The second screenshot above is a Transfer Rate Test, proving the disc is readable in that drive. :wink:


#4

[QUOTE=DrageMester;2016627]The second screenshot above is a Transfer Rate Test, proving the disc is readable in that drive. ;)[/QUOTE]Drage TRT’s are no good :\


#5

[quote=Bob;2016628]Drage TRT’s are no good :[/quote] Yes they are. Provided that CDSpeed is set to the accuracy seting for transfer rate tests, a successful TRT proves absolutely that the disc is readable in that drive.

A failed TRT proves that there are reading problems, but there would still be a possibility that the drive might read the disc if given the chance to slow down and re-read sectors. That can be further investigated by e.g. a ScanDisc test.

Whether the files contain random data, video, or secret plans for building the Death Star, makes no difference.


#6

[QUOTE=DrageMester;2016631]Yes they are. Provided that CDSpeed is set to the accuracy seting for transfer rate tests, a successful TRT proves absolutely that the disc is readable in that drive.

A failed TRT proves that the there are reading problems, but there would still be a possibility that the drive might read the disc if given the chance to slow down and re-read sectors.

Whether the files contain random data, video, or secret plans for building the Death Star, makes no difference.[/QUOTE]Provided the disc will play so…this test is flawed as there is no way to watch it and the disc was never copied back to the hard drive.

There has to be a better way to test discs and using Nero doesn’t do it.


#7

Bob. DL media is not used just for DVD-Movies. You can’t watch a data disc. :wink:
TRT is a perfectly good way of telling if a disc is readable. It’s a much more reliable way than a DQ scan. :wink:


#8

[QUOTE=Dee-27;2016669]Bob. DL media is not used just for DVD-Movies. You can’t watch a data disc. :wink:
TRT is a perfectly good way of telling if a disc is readable. It’s a much more reliable way than a DQ scan. ;)[/QUOTE]and the disc was never copied back to the hard drive. TRT’s are no good.


#9

Let me explain my past experiences and these are within the latest hours of testing:

I burned a disc and the QS and TRT showed a bad disc. I burned an .iso file to see if it would play. Not meaningless files like you and the other reviewers do.

The disc scored zero and the TRT was afu’d so i throw it in my set top player and no problems watching the DVD video.


#10

[quote=Bob;2016678]Let me explain my past experiences and these are within the latest hours of testing:

I burned a disc and the QS and TRT showed a bad disc. I burned an .iso file to see if it would play. Not meaningless files like you and the other reviewers do.

The disc scored zero and the TRT was afu’d so i throw it in my set top player and no problems watching the DVD video.[/quote] The bad TRT in your desktop drive proves that the desktop drive has problems reading the disc at full speed.

Watching the DVD with no freezing or skipping in your standalone DVD player proves that the disc can be read without major difficulty at normal playing speed in your standalone DVD player.

These are not mutually exclusive results; in fact this happens quite often.

There is no such thing as “meaningless” files for disc quality scans and Transfer Rate Tests; the drive and the software don’t care what those files contain - only whether they can be read and how many correctable and uncorrectable errors are detected by the drive’s error correcting layer.

If you can read a DVD by performing a TRT, you can also copy the files from that DVD using the same drive (provided that your harddrive has sufficient free space); The TRT actually reads the data on the disc, it just doesn’t write the data to the harddrive.


#11

[QUOTE=DrageMester;2016693][B]There is no such thing as “meaningless” files for disc quality scans and Transfer Rate Tests; [/B]the drive and the software don’t care what those files contain - only whether they can be read and how many correctable and uncorrectable errors are detected by the drive’s error correcting layer.[/QUOTE]No such thing? Please explain. If you cannot perform a real life test how will you know. If you cannot watch it or copy the disc back to the HDD then how is that test enough to prove it actually works? I have to keep repeating myself :doh:

[QUOTE=DrageMester;2016693]If you can read a DVD by performing a TRT, you can also copy the files from that DVD using the same drive (provided that your harddrive has sufficient free space); The TRT actually reads the data on the disc, it just doesn’t write the data to the harddrive.[/QUOTE]yeah sure but if that test is not being performed then how do we (the public) know?

There has to be a better way.


#12

All the years i have read on this forum and others i dont actually really understand all this testing lark!
If i buy an NEC 7200s write to it and read it and the TRT reports back its 100% at reading and for arguments sake has zero pie,pifs and no jitter,then people on the forum would then say this drive is great!

However if i then put a disc in this,(NEC 7200S) i recorded a year earlier on a samsung,LG Benq writer whatever (that also a year earlier proved the writer what ever it happenned to be was 100% error free) showed up errors and said it was junk!

How do we then say the NEC 7200S is a good drive,if the disc i copied a year earlier was read back 100% error free (a year ago)
Hope you understand.
The majority of drives write to discs okay and are ok reading them back again.
There needs to be a more conclusive way of testing any dvd writers.

People should only scan with a certain drive ALWAYS,this would then give people a alot clearer results to think for themselves.
For example Liteon thread some use verbatim media then post there results
1.person writes with a 203AP then scans with the same drive
2.person writes with a 203AP then scans with a dw2000
3.person writes with a 203AP then scans with a 1650
4.person writes with a 20A3P then scans with a 7203S
Dont see the point of a drive being outstanding at reading something it wrote itself!(NO 1.)

Now what would happen if the 1650 scan showed very different results?
Would it mean the drive that wrote it is rubbish,or does it mean the dw 1650 is rubbish at scanning?
On the forum people ask for a good reader/writer and 9/10 The 20A1S is at the top of the list,but then why in a 20A3P thread dont they use the 20A1S if its “known” to be a good reader?

Why is it so important for dvd writers to be able to read back discs they wrote aswell(apart from putting plain old pc data on them)
I think the majority of people on here more than likely put video on them for standalone dvd players console playback etc.
Like bob said over the years i have scanned various disc and TRT showed such bad results,people here would throw it in the bin,but they play back fine a my old cheap as chips player!
A writer is a writer so shouldnt review/scans etc praise manufacturers on their dvd writers, outstanding writing performance and not sl_g a drive off because its not as good a reader!
You have 1650/55 20A1 series of drives for reading!

DVD Writers are like your own written language,
I can read my own writing(which i should be able to I wrote it)
But i cant read all my nans writing.DVD are similar i think not conclusive enough.
I think threads on DVD Writers writing performance shouldnt be able to use the drive that wrote it,only “known” good readers i.e DW 1650/55 20A1 type drives.

Hope people can understand what i am trying to say:rolleyes:


#13

Excepting certain media / drive incompatibilities, any media written on any drive should read in any other drive, preferably at full speed.

Whenever I have a piece of media the quality of which is in serious question, I don’t bother with a Disc Quality scan, instead I go right to the TRT and ScanDisc tests. I have found that both add pieces to the puzzle.

With a TRT, a disc can have to slow down due to bad condition, still read the data and “pass” the test, but the graph will show you that the disc needs to be copied and then tossed. I once threw out a disc on the basis of a dodgy TRT result even though PI rates were not insane. This was back when my Sammy started coastering discs (and so I only use it for reading).

If I am not mistaken, the ScanDisc test does something similar, it does a Read Test, which adds another piece to the puzzle. I think that it attempts to read all sectors, showing green for perfect sectors, red for destroyed ones, and, most usefully, yellow sectors where lost bits can be corrected by the error correcting layer. (with CDs for example, 14 bits are used to represent every byte, leaving a redundancy and correction margin of 6 bits per octet). Besides if you’re watching the test unfold, you can see how fast its able to read (it tells you how fast its reading in the lower right corner), which gives you most of the benefits of a TRT.

I am most likely to toss a disc firstly based on the results of a ScanDisc test, secondly by a TRT. I would never toss a disc based soely on a Quality Scan, unless the results were crazily out of line with my expectations.

Therefore, a TRT and a ScanDisc both provide useful clues. A disc could pass a TRT at full speed but still have damaged sectors that you would only see in a ScanDisc test. But the TRT gives you a nice graph so you can review read speeds at the end.

I only use Quality Scans when I’m expecting an extreme result - when with Verbs, I expect uber-low PI rates or when a disc is unreadable (like some paper labelled discs I was unfortunate enough to recieve from friends and nooby-ass media distributors) to see just how correspondingly awful the C2/PI rates are as an indication of how bad the disc really is.

I would therefore recommend to anyone the following:

  1. If you’re prepared to sit and watch the test, do a ScanDisc test to check for data and error margin integrity, while you’re watching it you will get most of the benefits of a TRT. I.E. if the drive has to slow down to read the disc, you’ll know about it.
  2. If you need/want to do ScanDisc tests unattended, do a TRT separately.
  3. DQ scans can only really be used for more detailed examination of a disc once the other two tests given the all-clear. The lack of CU/PO Failure reporting in modern optical drives makes serious integrity checking via a Quality Scan next to impossible.

#14

[QUOTE=rob7bt;2071453]People should only scan with a certain drive ALWAYS,this would then give people a alot clearer results to think for themselves.[/quote]I don’t agree, I think just the contrary. A really good disc/burn reads back and tests well in any drive, which is to me the definition of a really good disc/burn. A disc that reads/tests great in 1 drive but poorly in the next is in my view a marginal disc/burn and not worth considering.

I’m selecting my media and burning methods this way. The resulting discs must test good in all my drives. I’ll never trust a disc showing problematic results in a given drive, and will never accept the excuse that “this drive is a crappy reader” or “this drive is not a good scanner” (unless this drive has issues reading or scanning ALL discs).

But to compare different burns of a given blank model, or to test for degradation, yes, the same drive MUST be used.

Now what would happen if the 1650 scan showed very different results?
Would it mean the drive that wrote it is rubbish,or does it mean the dw 1650 is rubbish at scanning?
You’re oversimplifying: these are not mutually exclusive, and other possibilities also exist.

  • The 1650 can be rubbish at scanning
  • The NEC drive can be rubbish at burning
  • The NEC drive can be OK as a writer but not good enough to produce a burn that would read well in all drives
  • The 1650 could be a pickier reader for this particular disc model (but could still be outstanding with other disc models)
  • … you can find other possibilities if you think about it some more (I found at least 3 more :bigsmile: )

On the forum people ask for a good reader/writer and 9/10 The 20A1S is at the top of the list,but then why in a 20A3P thread dont they use the 20A1S if its “known” to be a good reader?
You mean to test discs? Well, it’s not very useful to test with the best readers around. On the contrary, using picky readers to test discs gives far safer results. But I’m not sure that’s what you ask.
Why is it so important for dvd writers to be able to read back discs they wrote aswell(apart from putting plain old pc data on them)
I think the majority of people on here more than likely put video on them for standalone dvd players console playback etc.
Like bob said over the years i have scanned various disc and TRT showed such bad results,people here would throw it in the bin,but they play back fine a my old cheap as chips player!
In YOUR player, maybe. Why do you assume it would read OK in another player? That’s the main point of testing. Someday, maybe tomorrow, you could well have to buy a new standalone player. What then if the borderline discs don’t read well in the new player? :stuck_out_tongue:
A writer is a writer so shouldnt review/scans etc praise manufacturers on their dvd writers, outstanding writing performance and not sl_g a drive off because its not as good a reader!
You have 1650/55 20A1 series of drives for reading!
Why do you think that everyone uses several drives? Not everyone is a CDFreak, most users out there have a single drive to write AND read. These reviews adress all users, not only people who have several drives.
I think threads on DVD Writers writing performance shouldnt be able to use the drive that wrote it,only “known” good readers i.e DW 1650/55 20A1 type drives.
No, they should use known picky readers for reading tests, and several known trustable scanners for PIE/PIF/jitter tests.

I more or less understand your line of thoughts, but you have even more thinking to do IMO. :slight_smile:


#15

[QUOTE=SeanW;2071669]Excepting certain media / drive incompatibilities, any media written on any drive should read in any other drive, preferably at full speed.[/quote]:iagree: Yep.

I am most likely to toss a disc firstly based on the results of a ScanDisc test, secondly by a TRT. I would never toss a disc based soely on a Quality Scan, unless the results were crazily out of line with my expectations.
I’ve preached that a lot. Keeper/Coaster: basically TRT, not scans. But scans are nevertheless useful, as dramatically high reported errors are often an indication that the disc will have lesser compatibility with readers. A TRT often can’t tell this, unless you use a really picky reader for TRT tests. Plus other uses of scanning of course, like detecting surface/media defects, checking media consistency, choosing best firmware/ burning speed, checking for stability…
A disc could pass a TRT at full speed but still have damaged sectors that you would only see in a ScanDisc test.
I’m willing to stand corrected if someone can provide the data, but I think this is wrong, based on my own checks. The TRT is always the pickier of the two, so any issue a scandisc* could show in a given drive will appear in the TRT in the same drive.
I would therefore recommend to anyone the following:

  1. If you’re prepared to sit and watch the test, do a ScanDisc test to check for data and error margin integrity, while you’re watching it you will get most of the benefits of a TRT. I.E. if the drive has to slow down to read the disc, you’ll know about it.
    This is so impractical that I don’t think it can be recommended. :bigsmile:

Plus I think that a scandisc* is not needed when a TRT has been performed, except for curiosity, as I’ve never seen a disc showing damaged sectors in a scandisc* AND a perfect TRT (assuming both tests are performed in the same drive of course. :slight_smile: ) - but I’ll stand corrected if you or someone else provide data showing the opposite.

EDIT - “scandisc”: I’m referring to the reading test :wink:


#16

[QUOTE=Francksoy;2072079]I’m willing to stand corrected if someone can provide the data, but I think this is wrong, based on my own checks. The TRT is always the pickier of the two, so any issue a scandisc* could show in a given drive will appear in the TRT in the same drive.[/QUOTE]

This dates back to a few of months ago when I was re-checking the integrity of all my backups, most of which were/are CDs. While watching ScanDisc (Reading tests, not C/PI rate) tests, I saw the test running over some yellow blocks at high speed. I assume therefore, that a TRT wouldn’t have caught that.

I threw out most of the discs where I saw this happen (mostly CMC MAG) so I can’t go back and get proof. But I do have some marginal case discs (where scanning on one drive showed damage but another didn’t), if I can dig those up and my new hardware also finds questionable quality, I’ll do the scans again and post the results.

My assumption (and this is an assumption, I could be wrong) that “damaged” in a read test means correctable bit failures, seems to add up with a sitation where a drive can read the 14 bits per byte (CD redundency rate) at full speed making the requisite corrections as it goes.

From what I’ve seen scanning 200+ CDs with ScanDisc, most of the yellow blocks show while the disc is being scanned at full speed.

But if anyone knows for certain how CD/DVD speed ScanDisc Read testing decides a sector is “damaged” please share!

But when a disc is badly enough damaged (I tend to see this more with DVDs) that the drive has to slow down dramatically to read the data, a TRT is more useful because you finish the test and see a crazy speed graph, and a break in the line at any point of failure.


#17

I see. You’re assuming, and that’s what matters as far as I’m concerned. Not that I question your insight, rather I’m not convinced that small drops in the reading speed are detectable during a Scandisc test, because of the way the interface works. But these small speed drops will appear in the TRT… because it was designed this way. :slight_smile:

Allow me to give you a hint (no patronizing intended) about testing optical media and conclusions that one reaches: keep the assumptions as scarse as possible, and reality-check as much as you can. :wink: - I’ve also been assuming a lot when I first started testing, and this has lead me to numerous mistakes, some of which were dramatically foolish :rolleyes:.

I’m still not saying that you cannot be right about this, just that as it seems to contradict my own experience with TRTs and Scandisc, I have my doubts until I’m shown some actual graphs backing this up. :slight_smile:


#18

Here are two cases showing that there can be issues that a Transfer Rate Test will report though a Scandisc Reading Test won’t.

They don’t disprove however, that there can be issues that a a Scandisc Reading Test will report though a TRT won’t. But I haven’t met any such case. :slight_smile:

  1. Disc 1, TRT

  2. Disc 1, SRT (Scandisc Reading Test)

  3. Disc 2, TRT

  4. Disc 2, SRT (Scandisc Reading Test)






#19

The way I see it, which is based on my experience, a TRT in a fussy reader is the most sensitive test of a disc’s actual reading condition. Then comes the Scandisc, and finally the PIE/PIF scan, which often tells nothing at all about the actual reading condition of a disc, as it only reports some numbers about low-level reading errors. Useful for comparing burning quality etc…, but useless for checking actual performance.

Of course, drives that report POFs accurately during a PIE/PIF scan, turn a PIE/PIF scan into a far more useful test for real-world behaviour! Sadly, many don’t. :frowning:
Also, the fact that so many users scan at slower speeds (@4X, @8X), while being kinda backed up by scanning theory and ECMA standards, makes most PIE/PIF tests absolutely meaningless in terms of actual reading behaviour, which is nowadays expected to be flawless @12X, 16X, and even @18X in some drives. It’s easy to pass a @4X or @8X scan, (= show in-specs numbers), it’s another story to pass a @16X TRT in a picky drive without any slowdown. :stuck_out_tongue:

So the best discs/burns (in terms of current actual reading performance), are not those that show the lowest PIE/PIF figures in some end-user home scanner, but those that show a perfect reading curve in a Lite-On 16P1S or 16P9S DVD-ROM, or a NEC 4550A burner, or some other fussy reader.

On the other hand stability, consistency, low-level burning quality, are better checked with one of the usual consistent PIE/PIF scanners. TRT’s usefuleness, in this domain, is extremely limited, not to say close to none.


#20

[QUOTE=Dee-27;2016663][B][EDIT][/B] Some posts in this thread (including the first post) was copied from another thread so the validity of a TRT test on a data disc could be debated.

[B]12x DVD+R DL burn with a modified firmware[/B]

Media RICOH JPN D01c
Firmware 1.05 (modified)

It’s interesting that Optiarc uses a CAV writing method. The burn time is also pretty good.

The disc is readable, but the modified writing strategy doesn’t really suit the media.[/QUOTE]

Wohoooo!

Is that true Ricoh media? Same layer technology (not 2L) used as before?