Datavideo TBC -> Makes worse the picture quality?

[Fos]

Hi ,

I just captured a clip using my theater 550 , passing through the signal with the Datavideo TBC and without it.
I have transferred a lot of tapes and i didn't notice that the tbc makes darker and more saturated the picture than the original.
See the examples.


With Datavideo TBC



without it







I'm planning to never used it again or at least correct the contrast with the saturation always before capturing.

[BruceSD]

Funny you post this, because I found out about that today myself.

I had a tape I recorded a few years ago, a show on a third tier channel on my digital satellite (meaning it is overcompressed digitally to begin with, and then transferred to a VHS further softening the picture.)

The picture looked a little oversaturated, the material itself was dark so I figured the darkness was normal. I didn't realize it was making it too dark until I removed the TBC and tried it, in an effort to make the picture sharper. It made the picture a bit brighter, less saturated, and somehow a bit "sharper". It was not a night and day difference, but the difference was noticable and made the tape more pleasant to watch. I recapped the tape, with my Line TBC in my JVC on.

For what it is worth, I noticed the TBC-1000 "improved" the color in the way the JVC Line TBC did, but a bit more so.

I always assumed I should use the TBC-1000 always unless there was some sort of obvious playback issue. I have tapes that require the TBC-1000 or they will bounce from beginning to end, and the TBC-1000 was the only thing I tried that could eliminate the bounce so I am stuck with it in some cases. Ironically, those tapes look great with the TBC-1000, brightness color and everything.

Some of my tapes with content I recorded from my DBS actually looked ok with the TBC-1000, I used the TBC-1000 even though the tapes were a few years old, recorded in SP, recorded on high grade expensive tape and were in excellent condition with no 'need' for time base correction. But, this one tape seemed especially effected by the TBC-1000, maybe because the program was very dark, and soft to begin with?

I was going to post the question, should I only use the TBC-1000 for tapes which require it? Lordsmurf has said almost all tapes can benefit from the full frame correction the TBC-1000 offers. I was using the TBC-1000 in all cases, de facto.

[guns1inger]

I don't see your problem. Every tape requires it's own approach. Some will benefit from the TBC, some wont. If it doesn't improve the situation for one tape, don't use it for that tape. But to say "I'm never using it again" on the basis of a single tape is just childish.

[edDV]

What color space are you capturing to? Is this MPeg2 from the 550?

W/O TBC the picture shows crushed (below level 16) blacks and white overshoots (over level 235).


W/TBC the picture still shows blacker than blacks, but white is at level 235 or down about 5%.

[edDV]

Chroma is more saturated by about 8% with the TBC.

W/O TBC


w/TBC

[edDV]

Just played with the W/O TBC to set levels (split screen).

Black, set PAL blanking left edge to 0% (digital 16). A few pixels of blanking were captured left and right edges. Correction was +6%

White, set brightest point to 100% (digital 235). Correction was -4.5%.

Saturation was left alone.

[Fos]

Yes , it's MPEG2 format (cyberlink powercinema).

Thanks for you contribution edDV. I don't know why it have to change saturation and brightness values , it's worrisome !

This is a capture of the VCR menu , it's better for appreciate the difference.

with





without it

[davideck]

The picture looked a little oversaturated, the material itself was dark so I figured the darkness was normal. I didn't realize it was making it too dark until I removed the TBC and tried it, in an effort to make the picture sharper. It made the picture a bit brighter, less saturated, and somehow a bit "sharper". It was not a night and day difference, but the difference was noticable and made the tape more pleasant to watch.

I have also experienced similar behavior with the DataVideo TBC-1000 and TBC-3000. Sometimes the output is too dark. Sometimes it looks washed out.

The DataVideo TBCs are not transparent. Even on good tapes, I see deviations in brightness and contrast as well as softening. The TBC-3000 has proc amp controls that can provide adjustment of brightness and contrast to better match the output to the input. Rarely do I have them set to unity.

https://forum.videohelp.com/viewtopic.php?t=283639

These days I prefer to use my Toshiba DVD Recorder as my external TBC/Frame Synchronizer. It is more transparent and does a better job of timebase correction.