Testing issue

Rich Reilly wrote on 10/17/2007, 8:43 AM
I have a DVD-R that plays fine on 3 out of 4 hardware players and all software players we have available.
On the deck where there is a problem, it stops at the exact same spot on the segment. It happens even on different encode passes at CBR 7, AC-3 audio 192.
The deck is an old Pioneer DV-525 circa 1999 or so.
If it was a flaky machine, would it be so predictable?
Meanwhile, some $25 decks purr along without a problem. (Although I've noticed some subtitle dropouts on the cheapest.) Thoughts?


ScottW wrote on 10/17/2007, 8:54 AM
It happens. Probably a bit rate spike is bothering the player since it's at the same location every time. Anything in particular going on at that point? Fast action, transition?

One thing to do is get a bit rate analyzer to see if there is a spike at that point; as for getting rid of the spike, that's harder. Different encoder, lowering the CBR bitrate or going 2 pass VBR with a lower average and a lower maximum.

Rich Reilly wrote on 10/17/2007, 9:29 AM
A flash of video static, 2 or 3 previous to this one no problem...but it's CBR. Why would there be a spike?
ScottW wrote on 10/18/2007, 6:04 AM
CBR is not truly constant, it's a target encoders aim at and try to hit within a certain allowed deviation - its just that the deviation is much much smaller than what's allowed by VBR (usually).

Last time I ran into a player with this type of problem, it turned out to be a succession of small short spikes in a row that pushed the decoder over the edge. Switching to a different encoder resolved the issue. Changing the offending video in some fashion may also help (you might try applying a small amount of blur on that section, or slowing it down to reduce the frequency of change).

MPM wrote on 10/18/2007, 8:49 AM
@ Rich, FWIW & all...

IMHO if wouldn't hurt to try a cross-section of current players, as the average seems to be the drive mechanisms fail around 3 -4 years based on comments I've read. As to why the old unit -- besides wear I'd guess that most older players don't have as much memory as current models.

Of course media &/or burner selection can make a difference -- when something's marginal, making the task harder can cause failure.

Personally, if there's a problem with the vid I prefer to try and fix it, whether that means filtering or cutting etc... With digital it's hard to say how, when, where the effects of a bad section will show up. Not all encoders & decoders will process the stream the same way, or even consistently when there's a *hiccup*