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Discussion Starter · #1 ·
Here's a tip, drawn from a recent experience. Start recording from VHS after the "snow," since it might wreak havoc on a DVD recorder's encoder.


A VHS tape originally recorded on a full size Hitachi video camera had a 5 or 10-second lead-in of snow (unrecorded tape) before the recording starts. My first attempt to record this, played on a Sony SLV-N71, to my DVDR resulted in the first five minutes or so of the recording being highly pixelated, like a low-quality VCD or a WMV at about 200 kbps. After that, it clears up and looks fine.


When I saw the result, I went on the hunch that the snow at the beginning of the tape sent the DVDR's encoder into a tizzy. I had set the bitrate on the recorder to 7.2 mbps, but even so, it looked terrible right after the snow. Just a wild guess here but perhaps these machines record with Variable Bit Rate, not Constant Bit Rate, so after allocating a peak bitrate to deal with the complex and constantly changing video pattern of the snow, the encoder was tired and shagged out after a long squawk and only allocated a really low bitrate thereafter, according to the law of averages.


This preceding bit of pseudoscientific speculation does raise an interesting question, though: Do DVDRs record in VBR or CBR?


Anywhiz, I recorded the exact same tape with the exact same bitrate (7.2 mbps) again, but this time starting after the snow, and all was fine.
 

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1) This problem is mitigated through use of a DVD recorder with a HDD where you can edit this lead-in part out of the program before you commit to burning to disc. I have firsthand experience with this issue in the process of converting old VHS camcorder footage to DVD using my Panny EH-75V. (Another in the long list of advantages of using a HDD based recorder to initially digitially capture content before committing to a disc burn).


2) Most, if not all DVD recorders, record using VBR encoding (I know for a fact that all Panny recorders at least, and the few JVC/Lite-on DVD recorders I've owned all used VBR encoding - so this is the basis for my statement).
 

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Discussion Starter · #3 ·
1. The machine I used is a Toshiba RD-XS35, which does have an HDD, and that's what I recorded to first, before doing a High Speed Dub. It's not the few seconds of snow at the beginning which are a problem, since that can easily be edited out prior to burning as you point out, but the real problem is the five or so minutes of recorded footage, which is fine on the original VHS tape, that comes directly after the snow and which appears heavily pixelated, even on the HDD before any burning has taken place. So the problem seems to be in the encoding, which is discombobulated by the snow. As I mentioned, a second attempt, this time hitting the record button after the snow has passed, yielded good results.


2. VBR, you say. I would tend to agree with you; the experience described above gave me the inkling that's the case.
 

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Helps to have all the relevant information in the original post (like machine you were using and overall process) to get a better first response. In any event, perhaps an issue with the Toshiba encoder because I have not encountered that issue on my Panny, even recording entire tapes recored on VHS decks without a flying erase head (which results in glitches at start-stop transition points and garbled video for the next two-three seconds afterwards) have not caused behavior as you described on my HDD recorded segments.
 

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Discussion Starter · #5 ·
The occasional glitch and garbled video does not present a problem for the Toshiba either. It's just when I started the recording in the middle of 5 or 10 seconds of snow at the beginning of the tape.
 

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Quote:
Originally Posted by plplplpl /forum/post/14172762


The occasional glitch and garbled video does not present a problem for the Toshiba either. It's just when I started the recording in the middle of 5 or 10 seconds of snow at the beginning of the tape.

I might try some experimentation myself with snow lead-ins or similar long duration tape glitches to try to see if I can get the panny encoder to glitch. I know that when I lose the analog cable feed, it has no problem recording snow - lol!
 

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While I can see how the show might effect the initial recording, somehow calibrating settings incorrectly, I've never ran into this problem with my Pannys(ES-30 or separates). What I have ran into is if the autotracking sets wrong during the first parts of the tape it may stick for the rest of the tape. For that reason I push both CH UP and CH DWN on the remote to restart autotracking after the master tape had settled down. If you're running autotracking and tracking gets way off the autotracking will correct it, but sometimes if it's border line it may not. Also with (the ES-30 anyway) if you manually adjust the tracking it stays that way until the end of the tape. The autotracking doesn't restart unless you push the above 2 buttons to restart it.

Lots of things to consider when dubbing a tape, other than pushing a button and walking away.
 
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