G2 MSTC Time Base Corrector question

[Topsy]

Hello there,

Hoping someone might be able to help with a G2 MSTC Time Base Corrector query.

My setup is SVHS (Panasonic Fs100) > TBC > DV CAMCORDER > PC.

I've noticed that some tapes show horizontal distortion when playing back SVHS through the MSTC but not through DV directly. I carried out some tests with a PAL testcard.

https://youtu.be/DlcQ-NfLSd8

This is the recording off tape through the MSTC. You can see the horizontal distortion - particularly noticeable in the middle of the picture where the gratings are (first in VHS mode, then SVHS).

The odd thing is, I've checked the recording directly though the DV and it looks fine - even though I used the MSTC to pass the signal to the SVHS when I recorded it.

https://youtu.be/yhJZle2tIkA

Does anybody have an explanation? Are there situations where the TBC would make a picture worse from the VCR? Could the TBC be faulty somehow?

any thoughts welcome!

t

[JVRaines]

Your MSTC is most likely a frame synchronizer while your DV camcorder incorporates a true TBC. Only the latter will address line-by-line timing errors.

[johnmeyer]

Actually, the DV camcorder may not have much, if any, of a TBC. I think TBC was only found on the Sony "DV" camcorders which were called "Digital8." They used the same DV encoding, but recorded to a different tape that was an identical form factor to the 8mm and Hi8 tapes. I think those Digital8 camcorders did indeed have some sort of signal regeneration although it was never clear to me if it worked on "pass-through" video when the camcorder was used as nothing more than a digitizer. I just did a quick Google search which confirms this: the Digital8 TBC was only used when playing back from digital tapes, not from older 8mm and Hi8 tapes. Of course, I don't believe everything I find with a Google search, so others here will have to chime in.