Who to believe? (BenQ scanning vs. Lite-On scanning)

Second disc, an identical MCC 003 burned by Lite-On SHM-165P6S.

First scan by BenQ DW1620.
Second scan by Lite-On SHM-165P6S.

What the heck has happened here?

benqs don’t like reading liteon burnt discs and liteys don’t like bnq discs. the first disc looks good with both writers, the scan results are very similar.

Definitely not vice versa, as you can see in the first pair of scans. Lite-On has no problem whatsoever reading the BenQ-burned disc. In fact, it reports fewer PIEs and PIFs than DW1620.

The question is, can DW1620 [and other DW16xx drives that produce similar scans] be trusted to provide reliable results?

This is the second MCC 003 disc, burned by Lite-On SHM-165P6S, scanned and then read by BenQ DW1655.

The scan indicates a very marginal disc that should be barely readable even at 8x [the scanning speed], but the transfer rate shows a disc readable at 16x with no errors or even slowdowns.

If you look closely after the write speed bump LiteOn does something while writing that BenQ doesn’t like. The question now is… does LiteOn do something while burning that is out of the specs or does BenQ have trouble reading something that is within specs.

In such situation I always belive the drive which shows a less good scan… also this is a reason why I don’t trust LiteOn scans very much because it is a too good reader.

The transfer rate is normal as a slowdown only occures when a POF happens… If a POF doesn’t happend there is no need to slowdown (everything got corrected by the error correction).

Quikee, I agree with most of what you said, but here’s some more food for thought.

We are now looking at a TYG02 disc burned by Sony DRU-820A, scanned by BenQ DW1655 and then by Lite-On SHM-165P6S, followed by a transfer rate test by BenQ DW1655.

First, there is a power adjustment point at 120 MB where BenQ’s scanning gets thrown off by something and shows a tall PIF spike reaching up to 24, which is not present in the Lite-On scan.

Second, BenQ reports 172 POFs in 8x scanning, yet blows through the entire disc in 16x reading without slowdowns in places where you would expect them to happen.

Lite-On, on the other hand, exhibits no such unexplained phenomena.

Oh well, it’s late… maybe it will make some sense in the morning.

I have had a similar experience to agent009 with my 165P6S and DW1650. Using MCC 004 discs I had a good scan with the burner (165P6S) but a horrible one with the Benq with the PIFs and PIEs rising sharply at exactly the same point just below 1GB into the burn(scans below). Not happy with these result I then scanned the disc with my NEC 3450a (result in next post).

The conclusion has to be that the Benq is finding errors that are a “Benq thing” and that there is nothing fundamentally wrong with the burn.

nothing wrong here

I have also seen a number of media/burner combinations where the BenQ scans are way out of line with expected results. I have concluded that BenQs do not always provide reliable results with media burned on other burners. Nor do they provide reliable results with TYG02 burned on BenQ.

Trust the Liteon. Remember, scans are not a measure of burn quality as much as they are a measure of comparison between different media on the same burner or the same media on different burners. To accomplish this the scanner needs to be the constant in the equation.

Still a good burn is always a burn that gives good result on all scaning drives (and a scaning drive must not give bad(false) results on in specs problems). In this case the disc itself might be good quality (if quality is defined as longetivity)… but compatibility might suffer.

On the other hand quality in terms of longetivty can only be measured using multiple scans where disc is constant, the drive is constant and the time between 2 scans is relatively long. A single quality scan in this case is still inconclusive.

chas0039: What do you think? =) What is the type of quality we all measure today? It can’t be logetivity and it can’t be compatibility because both are inconclusive using only 1 drive, 1 disc and 1 scan IMHO.

On all the discs burned by the LiteOn, the jitter is VERY high. It’s well known that BenQs choke on high jitter when scanning. 15-16% jitter is WAY to high IMO considering DVD specs place the maximum jitter at 8 or 9%.

If I owned that LiteOn and it was producing similar results on alot of media, it would be heading straight to the trash can.

My thoughts exactly. And the upward shift in PIE/PIF in the BenQ scans happens at the exact same spot that the jitter increases sharply!

This shift in jitter (and PIE/PIF) also happens at the exact same spot as the LiteOn OPC stops and restarts, presumably with a changed laser power level.

With the evidence given I would say that the LiteOn burner is burning with sub-optimal quality, but the LiteOn and NEC drives are better at handling these somewhat problematic discs.

Scanning for jitter on another drive would help to decide whether the sharp jitter increase is “real”, if you have another BenQ or Plextor 712/716/755 drive to scan with.

Also drop your read speed in the Lite On to 4x.

I have to admit I am a newbie as far as jitter goes, but I have never seen any problems resulting from jitter. My reading on the matter indicates it is a problem related to audio only; am I correct? Also, is it possible that 8X reading increases jitter?

Some picky standalones have trouble with 13+% jitter. All I know is that DVDRs burned in BenQs, Pioneers, and Plextors usually do not produce jitter above 12%.

I am in the minority in that I believe that errors increase over time and, all things being constant, a disc with fewer errors will last longer as will a disc burned at a slower speed. I have no clue as to how long “longer” is so I don’t know if the quality I look at is meaningful or not, especially given that I will only be around for 34 years and my equipment for even less. We are all waiting for the NIST testing to finish so we can see what the real lifespan is for each media ID.

When I scan I am not concerned about whether my Liteon is a better reader than a BenQ as I am not measuring readability. I am looking for consistency and this is an area where BenQ has trouble.

When I scan, I am looking for a comparison with other scans, from the same media, so I can see if I am getting burns as close to perfect as I can. As all my burns play with no problem (RW excepted) I am measuring to achieve the lowest number of errors, both PIE and PIF. This is the basis of my rating system from a year ago. Now when I pick up a media to burn, I can go to my chart and see which drive/firmware will give me the best burn.

The forum has determined that the scan speed for 5 and 6 series drives is 8X not 4X as the two speeds return virtually the same results. My 1693 also is the same on both speeds. Some 1693s are not so I stay at 4X when I post. When my 165P6S arrives, I will post those scans at 8X to stay with the forum standard.

High jitter negatively impacts a drive’s ability to read a disc, and this gets worse the faster you try to read the disc.

If you have a disc with very high jitter you will often be able to detect this in a Read Transfer test, because the drive may slow down or re-read some sectors.

When you perform PIE/PIF scans, the level of PIE/PIF will usually increase when the jitter increases if you scan at high speed. This is clearly seen in the BenQ scans of the LiteOn burned discs above, and I see it frequently when I perform quality scans at 12x in my Plextor PX-712A drive, but I rarely see it when scanning at 2x.

I am not an expert in how this affects playback in standalone players however, but I presume that every player has a jitter level that it is “comfortable” with and if your disc has jitter above that level, the player will experience problems.

It’s true that the forum has decided on 8x scanning for this reason, but scans at 4x and 8x are not always equivalent - I have some rare cases of PIE levels increasing at the end of a disc in 8x scans but not in 4x scans on my LiteOn 1635!

I am aware there are exceptions. I didn’t mean to imply that they are identical.
Thanks for clarifying this.