PROBLEM with stand-alone DVD-R home recorders?

[mrlar]

Hi all. There's a major problem I noticed trying out different home DVD recorder decks, and I'm really worried now, trying to figure out if this is a problem with the RECORDERS (ie, on the newly-made discs), or on the PLAYBACK machine.

In a nutshell, many of the home DVD recorders "write to the disk" in blocks (the Sharp and Panasonics are in about 30-second blocks, and the new Sony is in about 35-second blocks). When discs recorded on these machines are played back on some other players, there is a noticable "jitter" (looks like a missing frame) EXACTLY at the point where the data is being written to the disc. However it is visible only when playing back on certain other DVD players, and not all. But this is making me worry -- if the problem is "on the disc" or not.

Here's the details (using normal DVD-R discs):
I bought a Sharp DV-RW2U a few weeks ago, and have made over 50 discs already (mostly old VHS stuff, some off LaserDisc). The Sharp keeps the recording data in memory, then writes it to the actual disc every 30 seconds, at 0:00:30, 0:01:00, 0:01:30, 0:02:00, etc.

Taking ANY disc made on this Sharp player, and playing it on my main player (a Yamakawa 218), there is a noticable "jitter" at EACH and EVERY :30 block (EXACTLY at the point where the Sharp has "written" to the disc). If it's fast-moving video (ie, a pan) you see it stutter for a second, and if a subtitle happens to first appear exactly at a :30 block, the subtitle jitters as well.

The weird thing is, this problem occurs ONLY on the Yamakawa player, and NOT on the others I've tried it on: my computer drive, an SMC, and a friend's Sony. Yet the Yamakawa has played ALL OTHER DISCS flawlessly, and the fact that this jitter is showing up (even if only on the Yamakawa) EXACTLY at the same spots (every 30 seconds on the 30 second mark) where the Sharp unit is writing to the disc makes me worry.

So much so, that I began to search for other recorders (I'll write a comparison post later). And I found the same problem. I bought a Panasonic E50 to try, and on that machine, the stutter is there as well (it writes it in about 30 second blocks as well). I even bought the new Sony home unit, and you can see the same "glitch" on discs recorded with the Sony (though the Sony writes in 35-second blocks, not 30-second ones).
Normally you'd just say "well the Yamakawa is a cheap player, so don't worry" but yes, even though Yamakawa is a cheap brand, this Yamakawa 218 player blows away all the other players I've seen, and I'm thinking (don't laugh) that it's TOO good, and is spotting errors the others are glossing over. Because again, it's not happening at random places, but exactly at the spots where the various recorders are writing to the discs.
Also, I have three Yamakawa players between myself and a friend (same model, one older version, two newer versions), and the problem occurs on all the Yamakawas, but the Yamakawas only. Different brnads of media were also tried, same result.

I noticed this only happened on the DVD-R (not DVD+R) recorders I bought, and the jitters were only visible using the Yamakawa to play back. I wish everyone could come over and see them, because they ARE there.

Since it's very important I have good quality copies of important old VHS tapes, I don't know if I should be worrying or not.

For anyone who has these recorders (the Sharp, Panasonic E50, new Sony), has anyone carefully examined their discs when played back on other machines to see if it's visible?

Any comments anyone? For those of you who own the Sharp, Panasonic, or Sony, could you check your DVD-R (I didn't check using RWs) using various playback machines to see if you see this?

Any thoughts? Should I be worried? Is it the discs that have this problem, or just the Yamakawas? Yet if it's just the Yamakawas, why is it so accurately "picking up" on this jitter right at the point where it's being written to the disc?

MrLar

[PhilipL]

Withdrawn

[mkelley]

Wow, after an impressive writeup like that (thanks, Phillip -- I learned a lot) what I have to say doesn't sound very important -- but I thought I'd at least give the poster some feedback.

I've been recording on my Panasonic for over two years now, and played the resultant disks on a wide variety of machines (no Kawasanki's, though :>) and never had even one problem... on the machines that play DVDR (older players exhibit a wide variety of interesting problems, but they do this on any DVDR I've tried).

So I don't think it's anything for you to worry about -- just buy a name brand player <g> and you ought to be okay.

[mrlar]

Thanks Philip for your reply.
With the "problem" appearing on discs pressed with not only the Sharp, but with the Panasonics (and now the new Sony) I'm sure someone else would have noticed it if it was a problem with the discs.

I suppose it's just a shame because even though the Yamakawa player looks like a toy, it's become my primary unit because I can find (until now) no faults with it. It's easily multi-region hackable, plays all discs, has excellent video quality (lacking in the Apexs for me).

I guess I'll have to find a new hackable DVD player. Time to check out the database (as many of my bought DVDs are R2s from Japan).

As for media used, I used both CompUSA 1x DVD-Rs (so-so), and Princo 4x DVD-Rs (absolutely excellent), both from different manufacturers.

In a way, considering the amount of $$ and time I've spent making the copies I have so far (backing up my LD collection and all my home VHS stuff) I'm relieved if it IS just the player noticing this. Just strange how using this player I'm able to detect right where each unit writes to the disc.

Anyway, thanks very much for your help.
If you have any other suggestions on any patches or any way around this (or any good hackable units sold in the USA) feel free.
MrLar