Tracking Error (TE) and Focus Error (FE) testing

Introduction

Most "scans" in the CDFreaks forum are quality scans of discs that have already been burned, but did you know that it's possible to perform scans on blank CD and DVD media before they are burned?

This type of test is called a FE/TE or TE/FE test and is possible on some Plextor drives using PlexTools Professional or PlexTools Professional XL, it's possible on some BenQ drives using QSuite and it's possible on LiteOn 6S series drives using DVDScan. Of these only the Plextor drives can run TE/FE tests on blank CD media.

Tracking Error (TE) measures how difficult it is for the drive's pickup to follow the pre-groove on the blank disc. If the laser goes partly outside the pre-groove while burning, the marks in the dye made by the laser will be poorly defined and harder to read.

Focus Error (FE) measures how difficult it is for the drive's pickup to focus the laser at the correct depth in the disc. If the laser isn't focused properly on the dye while burning, the marks in the dye will be weaker and harder to read.

We will have a look at TE/FE tests on blank DVD media using three different drives with three different software, and we will see if the TE/FE predicts something about the final burn quality as measured by disc quality scans.

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The drives and software used

Plextor PX-712A with PlexTools Professional
This drive will perform FE/TE tests on blank CD-R and blank DVD±R media. The tests are always performed at maximum write speed for the media which is up to 12x for DVD+R and up to 8x for DVD-R. The test takes as long as a real burn except for the lead-in and lead-out time.

Newer Plextor drives such as the PX-760, PX-755 and PX-716 will also perform the FE/TE test at maximum burning speed for that media which is up to 16x.

Here's a screenshot of PlexTools Professional and the FE/TE test:

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BenQ DW1655 with QSuite
This drive will perform a QScan (TE/FE test) on blank DVD±R media. You can choose the test speed (equivalent to a burn speed) and the sampling accuracy (Normal, Full, Quick, Smart, Customize). A Normal QScan can be performed in a little over a minute.

Here's a screenshot of QSuite and a Normal QScan:


Here's a screenshot of QSuite and a Full QScan:


Here's a screenshot of QSuite and a Quick QScan:


Here's a screenshot of QSuite and a Smart QScan:

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LiteOn SHM-165P6S with DVDScan
This drive will perform a TE/FE test on blank DVD±R media. You can choose the test speed (equivalent to a burn speed) and the sampling interval. A default TE/FE test at 16x can be performed in a less than 3 minutes.

Here's a screenshot of DVDScan TE/FE test (click image for full size):


This version of DVDScan doesn't automatically set the correct endpoint for TE/FE scans on blank DVD media, so you have to enter it manually in the LBAE (h) field. The correct size can be seen in the upper right "Disc" section as LBAE (230540), so just type this number into the lower left LBAE (h) field before pressing the [Test] button.

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Comparing scans and results

Now we will compare TE/FE scans of the same four DVDs using three different drives and tools.

HP branded CMC 16x DVD-R (CMC MAG. AM3)
This DVD was scanned at 8x in all drives because the Plextor drive cannot burn this media any faster than 8x.

Plextor PX-712A with PlexTools Professional FE/TE test:


BenQ DW1655 with QSuite QScan Full TE/FE test:


LiteOn SHM-165P6S with DVDScan TE/FE test (1000h interval):


There appears to be high correlation between the TE graphs from the three drives. Now lets see how the disc will look after burning.

The DVD was then burned on the Plextor PX-712A (fw 1.08) and a Sum8 scan was performed using PlexTools to see if the PIE had any relation to the TE/FE scans.

Here's the Sum8 (PIE) scan with the TE values from the three other drives superimposed.
The same scale was not used for all TE graphs but they have the same zero baseline:


There is possibly a slight correlation between the TE scans on the blank DVD and the PIE values on the burned disc.

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Verbatim 8x DVD+R (MCC 003) Made in India
This 8x DVD was scanned at 12x in all drives with Overspeed enabled in all drives.

Plextor PX-712A with PlexTools Professional FE/TE test:


BenQ DW1655 with QSuite QScan Full TE/FE test:


LiteOn SHM-165P6S with DVDScan TE/FE test (1000h interval):


There appears to be high correlation between the TE graphs from the Plextor and BenQ drives and some correlation with the TE graph from the LiteOn drive.

Here are the three scans superimposed on each other. The FE graph from DVDScan has been changed to a golden colour so that it's not confused with the QScan TE graph:


Now lets see how the disc will look after burning.

The DVD was then burned on the BenQ DW1655 (fw BCIB) at 8x (not 12x) and a Sum8 scan was performed using PlexTools to see if the PIE had any relation to the TE/FE scans.

Here's the Sum8 (PIE) scan:


There doesn't seem to be much correlation between the TE scans and the Sum8 scan in this case.
The BenQ drive burned this disc without any problem at all.

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Sony AccuCORE 16x DVD+R (Sony D21) Made in Taiwan
This DVD was scanned at 12x in all drives.

Plextor PX-712A with PlexTools Professional FE/TE test:


BenQ DW1655 with QSuite QScan Full TE/FE test:


LiteOn SHM-165P6S with DVDScan TE/FE test (1000h interval):


There appears to be high correlation between the TE graphs from the Plextor and BenQ drives but little correlation with the TE graph from the LiteOn drive.

Now lets see how the disc will look after burning.

The DVD was then burned on the LiteOn SHM-165P6S (fw MV9N) at 12x and a Disc Quality scan was performed using CDSpeed in the same drive to see if the PIE/PIF had any relation to the TE/FE scans.

Here's the Disc Quality scan with the TE values from the three other drives superimposed.
The same scale was not used for all TE graphs but they have the same zero baseline:


There is no clear correlation between the TE graphs and the PIE or PIF graphs.

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Verbatim 16x DVD+R (MCC 004) Made in India
This DVD was scanned at 12x in all drives.

Plextor PX-712A with PlexTools Professional FE/TE test:


BenQ DW1655 with QSuite QScan Full TE/FE test:


LiteOn SHM-165P6S with DVDScan TE/FE test (1000h interval):


Here are the three scans superimposed on each other. The FE graph from DVDScan has been changed to a golden colour so that it's not confused with the QScan TE graph:


A slight increase in TE and FE can be seen in all three scans, but it's not big enough to cause any problems.

This disc didn't have an interesting enough TE/FE scan to make further tests.

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An extreme example

The tests above are inconclusive as to whether you can predict anything about the burn from a TE/FE scan of the blank DVD. Sometimes however there's a very clear correlation between the TE/FE scan and PIE/PIF scans of the burned DVD.

This is one such extremely clear example.

The disc is a Fujifilm branded Taiyo Yuden 8x DVD+R (YUDEN000 T02) TG001133 scanned and burned on a Plextor PX-712A (fw 1.06).

Plextor PX-712A with PlexTools Professional FE/TE test:


Here's the Sum8 (PIE) scan with the TE graph superimposed:


Here's the Sum1 (PIF) scan with the TE graph superimposed:

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Some final words

We have seen some comparative TE/FE scans on three different drives, and noted strong correlation between the Plextor and BenQ scans and some correlation with the LiteOn scans.

Sometimes but not always the TE/FE scans will predict something about the final result after burning.

One of the things that wasn't apparent from the tests above is, that the drives will often automatically lower the burn speed for discs that have out-of-spec TE/FE values.

Since discs from the same cakebox or spindle usually have very similar TE/FE scans, it's usually enough to scan just a single disc per cakebox in order to know something about the rest of the discs in that cakebox or spindle.

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Last edited by DrageMester; 10-09-2006 at 01:11. Reason: Added info on DVDScan LBAE field

So what are your own experiences with TE/FE tests?

Do you have opinions or questions about these tests?

Do you find the tests usefull or useless?

Do you have some good or bad examples you'd like to share?

Go ahead and post in this thread!

Interesting comparison. Thank you for doing these tests. I'll have to dust off the TE/FE button on my copy of DVDScan.

FE/TE is probably most interesting for raw discs- it is after all the one test we can do on unburned media with consumer drives. Still, I'd be interested if you see differences in the reported values after burning the disc. In the one case where I managed this comparison, I didn't see great differences.

G

I haven't really performed that type of comparison (yet). If and when I make such tests, I will post the results here.

I believe I read somewhere that TE/FE tests can be misleading if used on media that have already been recorded. I'm not sure if this is true, however.

I just got some new MC 004 today and did a TE/FE test and all the other media I have tested has been a 'good' i.e. almost flat (still learning this) but this test had a lump in the centre, I then burnt the same disk and guess what...
This looks like a important test (if it works every time) and if you could back new media just opened

The few times I tried to run FE/TE testing with DVDScan that those results were the most inconclusive, and I never found it as complete of a graph as under Plextools with my 716a or my BenQ 1640. What I do find is sometimes indicative of a potential burn, but certainly not conclusive. Usually I found from FE/TE scans on my 1640 that there might be either PIE spikes at the same points where the TE spiked, PIF spikes at those occurences, or both PIE/PIF spikes at the same points. As a result, the only thing that seems slightly 'conclusive' to me is using the TE graph line, then comparing it to the PIE/PIF graph results and seeing if any spikes in PIE/PIF correspond spikes in TE values. Of course, the curious thing is that if I used VSO's CopytoDVD as the burning engine with MCC003 and used my BenQ1640 to burn it, the TE graph which indicated two major spikes in roughly the middle of the graph were matched by PIF spikes or clumping in those same areas. However, if I ran the FE/TE graph on the 1640, then burned the same MCC003 in my 165p6s with Imgburn as the burn engine, there was no PIF clumping or spikes like as burned with CopyToDVD on the 1640.

This is the second +R out of the batch I got from a computer fair on Sunday, and I see the same spikes (but not as high) in the same places (2.3 & 3~3.5 GB).

So far I have found this to be interesting, but two out of two does not mean much, so I will go thru all my other media and run this test to see if there can be a better correlation in the results, I have quite a range of TY and Verbatim media ATM because I have just got a new lot in. But I will post the scans from this MCC 004 batch in this thread, or make one of my own.

I have also been looking at the Plex PX-760A drive as it was a lot cheaper than I expected it to be and I see no real reason not to add it to my collection.

Quick post mainly for Drage (Hi ) - please bare with the telegraphic style, sorry...

I think your testing conclusions are somewhat irrelevant, from the fact you perform FE/TE tests at a given speed and then burn at a lower speed for disc #2, which is the only case without correlation from what I gather from my (extremely fast ) reading.

IMO only when the FE/TE scan is performed at the same speed as the actual burning speed can there be any relevance in a comparison between the FE/TE and a PIE/PIF scan.

In your demonstration, discs #1 and #4 (#3 = not burnt) with same speed for FE/TE and actual burning speed, DO (seem to) show a correlation...

My experience: FE/TE very useful for 16X burning speed of 16X rated discs, and for overspeeding of 4X/8X rated media, not very useful in other cases (haven't FE/TE tested low quality 16X discs, maybe this would prove interesting). (Hi Quema ) Makes total sense as a different burner will have different characteristics/performance for tracking and focusing on the same blank, and Drage's test above seem to show the Liteys cope easier with focusing and tracking (which could - could - be correlated with the fact they're so good readers).

The disc wasn't burned at a lower speed because I wanted it that way - the drive chose to do that by itself.

TE/FE scans at different speeds can be somewhat different but they are closely related, so TE/FE scans don't become totally irrelevant just because you burn at a different speed.

Nice to see you visiting the forum BTW.

I guess you mean in terms of trends in the graph, which is of course true . My point wasn't clear I guess (no surprise -never been writing so fast ): my take on this is that under certain FE/TE values, the impact on burning quality is either negligible or not detectable in "standard" scans. The FE/TE values have to be frankly "out-of-specs" for a given speed to show an impact on burning quality (burning at the same speed as FE/TE test) in PIE/PIF tests. I'm talking about the only FE/TE tester that I know of course, the Benq 1650 (never performed such tests with my former 1640).
The idea is that of some "treshold": below treshold, no impact on PIE/PIF (or negligible, or not measurable by our drives ), over treshold, possible impact. This "treshold" would be dependent on speed, so my remarks.
Haven't experienced with possible actul treshold values (far too complicated to test because of the multiple variables), I usually consider the criterias for TE/FE in Qscan as a dead line (pure wishful thinking). Incidentally, in my experience most "premium" media (MCC/TY/Maxell) do MUCH better in FE/TE scans than other media looking good in PIE/PIF scans.
Once again (you know my views on the subject), as the reading quality is speed/tilt/focus dependant, PIE/PIF scans @4X, @5X or @8X may well be useless to catch actual correlations, mainly near the end of the burns.
I hope I'll have more time in the next weeks to collect and post some graphs about this, but I still have my degradation report that is long overdue (among other DVD stuff that are long overdue ) so FE/TE reports will have to wait...

I'm really tired so I'll just mention that my 1640 really dislikes burning most media at 4x, and that the FE/TE scans show the same trend, 4x is pretty bad, 8x showing the best results overall, and 12x and up showing increasing levels again (not that surprising really). My experience is that I can usually use the FE/TE scans to determine roughly what the optimal speed is... I allways run it when opening a new spindle.

Unfortunately I don't have shots of the FE/TE scans I think, but I'll check if I cand find some later on.

So much for just making a quick post. :/

From my point of view I found the test I did on a batch of MCC 004 to have been true for every disk I have burned from the tub. I have 5~6 left and the best (PIF's) scan I did is below.
It does show the same problem points all the way thru the batch, not to the same extent of the first few, it has got better, but the same two problem points are on almost every disk, all have the 2.7 to 3.5 GB cluster.

I will be doing this test on new media I get from now on.

I will be getting a Plextor drive so I can use that to scan the TE/FE, I just need to make my mind up as to which one but that is for another thread.

Does not seem to want to let me to upload the image so I have had to put the same one, done at 8x (without jitter) in here.

thank you DrageMester for the excellent work I'm learning more and more day by day from this forum

I found here that DVDScan's TE/FE test is not supported by 5S Lite-Ons but I've already done the tests so want to share them the media is Verbatim DVD+R 16x YUDEN000 T03 (50 cakebox, TH000020 batch) tested at 8x, 12x and 16x with Lite-On SHW-1635S YV6P FBD.

and here are Lite-On LH-20A1H LL0A FBD scans at 8x, 12x and 16x with the same media tested above. I didn't expect that 20A1H would support TE/FE test. the 20A1H tests take minutes whereas 1635S "tests" take seconds one question, is the drive and/or the burn affected by the DVDScan's TE/FE test as BenQs are??

I consider that quite unlikely. I can't say I have investigated it, however.

Two cases that *seem* to show that at least for these blanks and this burner, FE (focus errors) seem to be more correlated with burning quality than TE (tracking errors).
Both @8X burns in 1650/BCDC, SB OFF, WOPC ON.

I''d have to do more tests of course: to confirm the trend, I'd need a disc or two with higher TE and lower FE that would show OK scans....

BTW I'll take those Imation-branded MBIPG101 R04 off my "favorite discs" list, as my recent spindles are more and more problematic. Many defective discs and poor performance after 3.5GB with most discs. Bye bye sweet alternative.