REAL-TIME DUB (RTD) INFO
The procedure for dubbing is in a separate help file here.
Important: A RTD from HDD to DVD sets the DVDR default rec mode to whatever you select for the RTD. Always check your default rec mode after a RTD!
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Notes
Note on Helpful Advice from Users of Other DVDRs
Making Multigenerational Copies in Same Rec Mode - Digital Channels
Mode-Conversion Dubbing from 1-hr-HQ to ALL Other Rec Modes - Digital Channels
Mode-Conversion Dubbing from 2-hr-SP Tape to 2.5-hr-SPP DVD
Real-Time Dub Smooths Edit Points
Notes
- The reason we can fit only 4424 MB, or 4.4 GB, of info on a "4.7 GB" disc is simply the difference in figuring capacity: disc mfgrs use the decimal numbering system (K=1000) but our DVDRs and computers use the binary system (K=1024).
- High-speed dub (HSD) retains ALL chapter marks in the DVD copy (auto- and custom-set). real-time dub (RTD) strips those and sets marks only per your auto-chapter setting in the Recording menu.
- When dubbing from DVD to HDD, you have to set the HDD rec mode since the dub doesn't occur automatically at the same rec mode as the DVD. Only a high-speed dub from HDD to DVD does that.
- A dub is controlled by the machine so, once you start the dub, you can walk away... you don't have to babysit a dub.
- Caution: Don't start a dub if you have a timer rec program due to start within the time period of your dub. You'll just end up ruining your disc!
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Note on Helpful Advice from Users of Other DVDRs
Be aware that, when people with OTHER DVDRs offer advice on recording and dubbing modes, etc., they might not have digital tuners in their units, so their source PQ is not as good as your digital channels.
Also, they certainly don't have Philips new MPEG-2 encoder-decoder (CODEC), one of hundreds they've developed, which has advanced features like those mentioned in a recent magazine article about the "big four" codec producers [Zoran, ESS, LSI and Philips] and who's doing what with their DVD chips, part of which reads:
"Philips is adding to its new MPEG-2 CODEC optimized hardware blocks for running new picture improvement algorithms such as adaptive picture sharpness detection and deblocking* artifacts removal."
So, do your own tests and become familiar with YOUR unit's capabilities, and you might be surprised at how "old" advice is, well, just OLD!
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Making Multigenerational Copies in Same Rec Mode - Digital Channels
Note 1: This discussion assumes recording from digital channels... recordings from analog channels will be hard-pressed to retain PQ, much less improve it!
Note 2: These RTD multi-generation tests were all done with the INTERNAL DRIVES of a 3575. You WILL get different and lower-quality results if you introduce an outside source, like a DVD recorded in a diff. recorder, a separate DVD player, Composite or S-Video cables, etc.
High-speed dub (HSD) is ALWAYS best to use IF POSSIBLE. However, there are some occasions that you might want to or need to use real-time dub (RTD), or mode-conversion dub, like when programs run long and you don't want to Delete Scenes, or you do all your recordings at 1-hr-HQ cuz you value VIEWING quality over subsequent ability to put on a disc, etc... "special" circumstances, for the most part.
For more info on RTD and HSD, click here.
Prompted by one of the Panasonic Super-Fans who bought a 3575 to bash and posted that an HQ multigenerational dub "looked like crap," and me thinking that sounded suspiciously untrue (as usual), I decided to test the
very-worst-case scenario of making sequential dubs, from one generation to the next
with the internal drives,
ALL in RT. That's definitely "worst-case" since, in the real world, the dubs from HDD-to-DVD would
normally be made at HS for a lossless, mirror-image copy.
I started by recording 30 min. or so of an action movie at 1-hr-HQ rec mode from my excellent TNT digital channel (Gen 1), which I receive via an analog cable feed. It has lots of detail shots, fast movement, closeups of faces, C4 explosive blocks w/small writing, a detonating device with a small LED and text, helicopter flying with inside shot of heads-up display, etc. IOW, LOTS of stuff that would normally show PQ degradation.
I copied the Gen1 HQ title from HDD to a DVD+R (Gen2), back to HDD (Gen3), back to DVD (Gen4), back to HDD (Gen5), and back to DVD (Gen6)... all RT dubs from the last Gen using 1-hr-HQ rec mode.
Theoretically, there was supposed to be
some degradation, but I just couldn't see it. I've got 3 copies on DVD... representing SIX REAL-TIME GENERATIONS... and ALL look virtually the same!
I wonder how many gens I could stretch that to if my original feed were OTA or Sat HD to start with, or even true digital cable, rather than my basic analog cable feed!?
If you need to do this multi-generational dubbing for a special purpose, you should, of course, use HS dub from HDD to DVD, then the Gen6 RT dub in my worst-case test would only be Gen3.
Even if you start with a
Finalized DVD in HQ mode from a good source, where the Gen1 on the DVD would have to be DIRECT DUBBED in RT to the HDD (Gen2), this test proved that a worst-case Gen5 from a Finalized HQ DVD can be virtually indistinguishable from the original, depending on the quality of the source.
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Mode-Conversion Dubbing from 1-hr-HQ to ALL Other Rec Modes - Digital Channels
Note 1: This discussion assumes recording from digital channels... recordings from analog channels will be hard-pressed to retain PQ, much less improve it!
Note 2: These RTD mode-conversion tests were all done with the INTERNAL DRIVES of a 3575. You WILL get different and lower-quality results if you introduce an outside source, like a DVD recorded in a diff. recorder, a separate DVD player, Composite or S-Video cables, etc.
Another question might be how good is this DVDR in maintaining PQ with a RTD that converts rec mode from a digital channel recording to one of the next-lower quality modes... again, in prob. the worst-case for source (other than an analog channel): my basic analog cable feed?
This is useful for someone who is primarily a "time-shifter" (record shows, watch later, then delete), but wants the highest quality recordings to VIEW. The true time-shifter seldom makes DVD copies so the 1-hr-HQ per DVD limit will only be an occasional "time-problem" that might require a real-time conversion dub to another rec mode... and even then, just for movies or special events that are over 1-hr in length.
I just completed several tests of RTD to check PQ loss from a 5-minute segment I recorded to my HDD in 1-hr-HQ. This DVDR allows you to pause a manual recording and change channels, so I did that to make sure I included sports, dramas, commercials, etc. in my test recording.
My results are summarized below with separate PQ assessments for a Drama (Las Vegas) vs Sports (BB & FB), PLUS the commercials, which were of different quality (RedLobster looked delicious at any rec mode
).
I was able to get a good assessment of the original PQ cuz I watched each RTD, looking for key areas to compare, like the effect of fast movement on edges, facial sharpness, etc. "Excellent" means I could not see a diff. from the original. "Good" means there was some visible softness but really hard to tell w/o a direct comparison to the original (i.e., I wouldn't have noticed anything "wrong" w/the pic if I hadn't seen the original.... many times!). "Fair" and "Poor" mean there was increasingly noticeable softening, mosquito noise, fuzzy edges, etc.
Mode-Conversion Dubs from 1-hr-HQ to Other Rec Modes with Internal Drives
From 1-hr-HQ rec. of digital HD channels in analog cable feed
RTD Mode | PQ Drama | PQ Sports* |
---|
2-hr-SP | Excellent | Good |
2.5-hr-SPP | Good | Good |
3-hr-LP | Good | Good>Fair |
4-hr-EP | Good | Fair |
6-hr-SLP | Good | Poor |
*See this help file for info on recording fast-action field sports where fast-moving players are teeny-weeny objects on large field.
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Mode-Conversion Dubbing from 2-hr-SP Tape to 2.5-hr-SPP DVD
Note 1: This discussion assumes recording from digital channels... recordings from analog channels will be hard-pressed to retain PQ, much less improve it!
Note 2: These RTD mode-conversion tests were all done with the INTERNAL DRIVES of a 3575. You WILL get different and lower-quality results if you introduce an outside source, like a DVD recorded in a diff. recorder, a separate DVD player, Composite or S-Video cables, etc.
I copied a 1994 commercial VHS movie from the original tape to my 3575 HDD in 2-hr-SP rec mode using COMPOSITE Y/W/R RCA CABLES, which is considered by many to be lowest quality connection. So, my reported results here should be considered as WORST-CASE since S-Video connection should produce an even better end product.
The SP HDD title turned out to be 2:22:05, so too long to fit on a DVD with HSD (2:10:00 max.), so I dubbed the movie to a DVD-R using AUTO, which selected the SPP mode (nearest, best mode for total length).
I asked my wife, who has critical nose and eyes, to see if she could tell any difference between the SP original and the SPP copy on disc. She said there was a "very minute" difference in PQ.
Based on my experience with mode-conversion dubbing of digital HD programs
using the internal drives, I believe if I had used an S-Video connection instead of composite for the original copy-to-HDD, she wouldn't have been able to detect that "minute" difference cuz the original copy on HDD would have been a better source for the SPP conversion.
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Real-Time Dub Smooths Edit Points
One other benefit to RTD is that it re-encodes the entire program, which recreates the Group of Pictures (GOP) that are disrupted when we delete scenes. This makes those edit points smooth again since the MPEG2 stream has been recreated in new GOPs.
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