07-11-2020, 11:19 AM
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Hi there
I just have a short question.
Today I connected an old Samsung flat-screen ( UE22D5003BW ) to preview some tapes. And wow: Incredible clear picture, steady as a rock.
It pains me that the cheapest flat-screen I could find ( few years ago ) is doing a great (better) job at correcting the time base, removing some of the noise and up-scaling it wonderfully. Even when there is a glitch in the tape, the tv won't budge, while the capture card is going berserk (going blank).
Somebody knows what magic these flat-screens use to get the picture that steady?
If only I could get the signal back out.
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Someday, 12:01 PM
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07-12-2020, 07:24 AM
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Basically TV designs cope with the variations in signal quality commonly found in the wild. They effectively rebuild the sync/control signals used to decode and display the image. Also, some models included auto-color correction and noise removal features. TVs could afford this at moderate price points thanks to high volume sales. Note that the automatic color correction and noise filtering may not be desirable in a capture card (unless it can be controlled).
Most capture cards, especially professional level and the low cost consumer ones were designed assuming the input signal is good and solid.
- Professional level because they assume professional gear in the chain that assures a good signal.
- Modest priced consumer gear because it costs less to design around a clean signal and price-point determines sales in what amounts to a niche market.
- In either case proc amps, TBCs, etc. may be necessary in the signal chain to ensure a good signal for capture. The professional studio just naturally does this. The consumer learns by trial and error.
(FWIW: I had an RCA set from the 1980s that did offer analog video output signals. I suspect that ended feature came to an end in part due to copy protection issues.)
Last edited by dpalomaki; 07-12-2020 at 07:35 AM.
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07-12-2020, 11:22 AM
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For whatever reason, even though there's a demand for capture dongles to capture video tapes, it seems most manufactures of video capture dongles not bothered to make ones with some TBC functionality built in or give it much thought, even though there are chips out there with this built-in. I guess whatever is sold is "good enough" for most people.
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07-12-2020, 02:21 PM
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Quote:
Originally Posted by hodgey
For whatever reason, even though there's a demand for capture dongles to capture video tapes, it seems most manufactures of video capture dongles not bothered to make ones with some TBC functionality built in or give it much thought, even though there are chips out there with this built-in. I guess whatever is sold is "good enough" for most people.
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Not good enough it's rather cheap enough. I've discussed this with the lead engineer designer at Ensemble Designs and asked him if they could revive the BE75 production in a new design by adding a USB 3.0 port instead of SDI (because the BE75 is almost an all in one device except no USB capture port) and he pretty much said that the final cost for such a product will far exceed the target's budget due to mostly chip licensing fees. That's true, the average person is looking for a $20 capture device with a stripped down design that barely carry a signal, and those companies such as easycap make money by selling large quantities, The quality is not the goal, just profit. So don't hold your breath for an all in one high quality capture card/device.
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07-12-2020, 04:03 PM
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The TV doesn't have a TBC, but rather it is more forgiving. This is due to the nature of the tech, not something merely not included in capture cards. Capture cards and TVs/HDTVs are way, way different. It's like cats vs. potatos, or dogs vs. candy canes. Just no comparison.
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07-12-2020, 06:53 PM
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Quote:
...whatever is sold is "good enough" for most people...
...Not good enough it's rather cheap enough....
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Any product brought to market must recover its costs; design, certifications, parts, product liability, licensing fees, copyright compliance, distribution, retail chain markups, profits at each step, and so on. And that is the crux of the matter. The world has moved on to HD and UHD, digital content & broadcast, streaming content, and that is where vendors see the numbers, the demand, the money and future sales. Most people at this site looks for serious high quality. They are the "1%-ers" with respect to video conversion quality. The guidance available here can help you achieve that.
Most consumers are just looking for something that they can see and hear from the old tapes. A bit of image jitter, snow, off colors, and smear is ok for them - and it hides grandpa's wrinkles .. (Consider the ever popular Rodney King videos) - Content counts more than quality. If it looks about as good as the tape played in their $39, 30-year-old VCR they are content with the conversion.
Think of it in terms of coffee. Some folks are particular about the grind, the type of filter, water temperature, roast, bean origin, and so on. Others are happy as long as it is hot and approximates dark brown to black.
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07-13-2020, 06:44 AM
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Quote:
Originally Posted by lordsmurf
The TV doesn't have a TBC, but rather it is more forgiving. This is due to the nature of the tech, not something merely not included in capture cards. Capture cards and TVs/HDTVs are way, way different. It's like cats vs. potatos, or dogs vs. candy canes. Just no comparison.
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While that hold true for old CRT, which are analog all the way, I think you might be mistaken about the modern flat-panel TV. These TV's need to convert the analog composite signal to digital, so the LCD (or LED) panel can display it.
... Or maybe you are right in some other way, that I'm going to discover soon ;-)
I did make some progress as to acquire that "digital" signal. It seems flatscreen TVs all use LVDS (Low-voltage differential signaling) as a way to "move" the picture from the main board (that digitizes/captures the signal coming from SCART) to the flat panel driver. It can be converted back to HDMI using a few components. ( Discussed on the forum at Texas Instruments / easy to google "lvds to hdmi") A fully build version is available on Aliexpress.
I'm planning to intercept and re-serialize the LVDS to HDMI (sacrificing the TV in the process I guess).
I'll keep you posted of the luck or failure when getting the video out of the LVDS. ( <-- or did someone already try? )
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07-13-2020, 12:27 PM
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HDMI really is not a capture port, It was designed to display video signal, sure you can capture from it using an expensive capture card that was designed for progressive HD video games but not interlaced digital SD. If you insist in capturing video from HDMI and have an over saturated, wrongly de-interlaced picture then you don't need to butcher a TV just get a DVD player with HDMI out and hook it up to the VCR or better yet get a combo VHS/DVD player with HDMI out, they do stabilize picture as good as any TV if not better.
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