Cleaning Cable TV Signal en route to DVDR

[benjiii]

Esteemed Fiends,

Here is my one goal: I want to make the cleanest possible dvd recordings of the Turner Classic Movies films that I receive via cable tv. (I'm a professor of film history, so it's especially important that I have the best possible raw material for making Quicktime clips and Powerpoint slides). I have found a valuable method, using a Canopus ADVC-300 digitizer -- but it is problematic method. I hope you can offer some insights.

My current set up, in simple form, is this: coax cable into cable box => out from cable box using svhs output and into ADVC-300 => out from ADVC-300 using svhs output and into dvd recorder (I use a Pioneer DVR-520h, and also have a Panasonic DMR-100h). (The set up is actually a bit more complicated, since I use a laptop connected to the ADVC-300 to take advantage of the wider array of image enhancements available via the Canopus software control, instead of just using the hardware buttons -- but this is not pertinent to the questions at hand).

I get superb results much of the time. The image/recording quality is MUCH better than just a straight cable feed into the dvd recorder. There's so much less noise (and I can get rid of color pollution by totally desaturating the image for black and white films).

The problem I am experiencing happens when Turner Classic Movies plays an old movie that had a wobbly time of it going through the telecine (as might happen with a warped or shrunken celluloid print). If there is any sort of pronounced flutter or wobble in the original film, my digitization creates a disconcerting effect where the image shows a strange sort of undulation. Objects seem to hover, switch back and forth quickly from foreground to background, undulate in and out, detached from their actual location. None of the adjustments on the ADVC digitizer offers any improvement. I think it is simply something that happens with any sort of digitizing of a fluttering/wobbling image. It creates a kind of liquid image similar, I gather, to what happens to the surface world during an LSD trip.

The problem, I believe, is with digitizing per se. It could be from the cable company's digital feed, not just my Canopus intervention. My colleague saw the same problem when our local cable company switched the TCM feed from analog to digital a few weeks ago. The solution he learned about was to bring the coax into the dvd recorder first, and then out to the cable box and then back to dvdr via svhs. Apparently the dvd recorder converts the digital signal to analog somewhere in the process. I can't claim to understand how it works, but it does work. It solved the problem. But it's not a solution for me, because I still want to clean up the image.

So, I have two questions:

1) Does anyone know of any ways to get rid of this LSD digital effect when recording wobbly films? If not (assuming it is intrinsic to the digitizing process):

2) How else can I clean up the cable tv feed en route to the dvd recorder?

With respect to the latter question: having read this forum, I purchased a top notch Image Enhancer and Proc Amp (the SignVideo DR-1000 and PA-100 units), hoping I could keep everything in the analog realm and get rid of the digitizing altogether.

The results were very disappointing. I bought the image enhancer because I saw from the online pic that it had "Noise Reduction" knobs. But upon testing it and reading the manual, I learned that the noise reduction adjustments only pertained to NEW noise created by the unit's other sharpness and detail adjustments. It does nothing to clean up the source video signal. I can well imagine the unit helps a great deal when transfering videos, but for my application, it was disheartening to see that all of the DR-1000's adjustments made the cable input look much worse than the original unenhanced feed (and, believe me, it's not because I wasn't using it expertly). The best image by far was "unity," i.e., bypassing the instrument altogether. As for the PA-100, it certainly is a nice unit, with a helpful meter, but without noise reduction, it is moot for my purposes. If I have to go back to digital, I can do everything it can do using the ADVC-300 (which actually offers even more types of adjustment).

My question boils down to this: Will a TBC (the TBC-1000 or one of the others in the $200-300 range) make the cable signal come in cleaner, sharper, less noisy? Or does a TBC only fix problems associated with videotape transfers? I would think that things like jitter and synch are irrelevant regarding a cable feed. (Note that I'm not looking for something to correct the jitter or wobble of the old-movie telecine transfer -- I don't think that would be possible). I just want less noise -- less roughness, buzziness, etc... before going into the dvd recorder. Will a TBC help with cable? Would anything else?

Thank you very much for any help!

Ben
Madison, WI

[edDV]

Esteemed Fiends,
...

My question boils down to this: Will a TBC (the TBC-1000 or one of the others in the $200-300 range) make the cable signal come in cleaner, sharper, less noisy? Or does a TBC only fix problems associated with videotape transfers? I would think that things like jitter and synch are irrelevant regarding a cable feed. (Note that I'm not looking for something to correct the jitter or wobble of the old-movie telecine transfer -- I don't think that would be possible). I just want less noise -- less roughness, buzziness, etc... before going into the dvd recorder. Will a TBC help with cable? Would anything else?

Thank you very much for any help!

Ben
Madison, WI

I read through this and can't see much more you can do for DVD recording. There are always higher end noise reducers.

A TBC shouldn't be necessary from a cable feed and probably would harm the signal. TCM is probably playing back from a server and the source tape is most likely digital Betacam. The telecine and color correction were most likely done in a separate post house.

[gshelley61]

Digital cable streams are highly compressed MPEG2 and the channels can vary widely in picture quality. You are probably seeing digital compression artifacts and flaws (macroblocks, mosquito noise, image smearing, etc.) A TBC is not needed for digital video signals, and might actually degrade the image.

The SignVideo DR-1000 enhancer and the Proc Amp you have should be useful for mild tweaking of the image, though I don't think you can make a digital cable source much sharper than it already is. It also depends on how well the cable box converts MPEG2 to s-video. Sometimes these cable boxes do not have the best quality analog signal outputs. The Proc Amp can be used compensate the cable box NTSC s-video output black level from 7.5 IRE down to 0 IRE (necessary for a proper digital capture), keep the luma from exceeding 100 IRE, and to adjust the color if necessary. The noise reduction knobs on the DR-1000 only work when detail or sharpening is used - they help reduce noise introduced by image enhancement (from boosting detail and sharpness). They don't do anything for noise by themselves, and cannot help MPEG2 compression artifacts.

The digital cable box is converting the digital MPEG2 stream into a s-video NTSC analog signal. If there are digital compression artifacts in the image (macroblocks, smearing, etc.) that means they are part of the digital stream and can't be eliminated.

Recording the s-video signal directly with a DR-M10 JVC DVD recorder may help somewhat, because it has input video noise reduction filtering that is pretty effective, and on DVD playback applies MPEG2 compression artifact/noise suppression.