External line tbc's are found as expensive shop units that require ancillary equipment. And $$$. Usually you get a hlgh-end SVHS VCR with a line tbc built-in. Those aren't cheap, either, and a real trek finding one that hasn't been used to death. The other way to get line tbc activity for $100 or often less is to use an older DVD recorder that can be used as a pass-thru unit. You don't record to a pass-thru -- connect the VCR to the DVDR input, then connect the DVDR output to the rest of the capture chain. You don't record the video, you "play thru" the device. A line tbc has to run in circuit before
the signal gets to a frame tbc. Few DVDR's can be used for pass-thru, and most that can will not perform well. The favored models are the Panasonic DMR-ES10 and DMR-ES15.
A common but rather mild example of line "wiggles" produced by typical scanline errors without a line tbc is here: http://forum.videohelp.com/threads/3...=1#post1882662
. The "fixed" version shown used a DMR-ES15 for line tbc pass-thru.
More severe examples were posted in several threads here. Below are links to 2 samples of scanline errors. The tape was played with a non-tbc VCR. While the bad demo looks like a severe case, it's not as uncommon as you'd think an often appears as less severe but similar and obvious. This sort of top-border flagging and frame slippage happens often with old tapes. Some tapes will play without this severity, some won't. All VCRs without a line tbc will have scanline errors.
is the original capture encoded to MPEG, with frame size slightly reduced to prevent TV overscan from hiding some of the problems.
is the tape played with a line tbc pass-thru device.
The "fixed" sample linked is a first-stage test repair with only basic denoising, improved afterwards with a better VCR but here addressing only specific issues. The tape is no longer available.
The sample links were last posted in digitalfaq 2 weeks ago.