VHS Digital Transfer Expectations
- Steve Puffenberger
- Home Video
Why transfer of VHS to digital looks the way it does
Face it, we’re spoiled. Since the Digital TV revolution in 2009, we’ve all ditched our CRT “tube” TVs for big high definition and even 4K flatscreens. The pictures on air, on cable and even streaming services are breathtaking. And even home movies taken on our digital camcorders or phones are sharp and clear thanks to advancements in cameras and recording formats. So why, when you have your box of VHS tapes transferred, does the picture comparitavely look like crap?
Unfortunately, the short answer is, “it is what it is.” Here’s the short version of a very long story, and be prepared for some math:
The Video Resolution Spectrum
Modern TVs work by illuminating millions of little “tiles” of color on your screen, just like the tiles on your bathroom wall. We assess video quality by counting number of tiles (called Pixels, for Picture Elements) in the horizontal and vertical dimensions. That's called "resolution." Obviously, the more pixels there are the higher the resolution, and the higher the resolution the sharper the picture. Right now, we’ll talk about the number of rows of pixels.
With High Definition and 4K TV sets, you have a LOT of rows of pixels - see the illustration. The latest 4K TVs have 2,160 rows of pixels counting from top to bottom. The previous deluxe "Full" HD models have 1,080 rows. And before that came the 720 row standard. Currently the broadcast standard is either 720 or 1080. ABC and FOX broadcast in 720, and NBC, CBS and PBS broadcast in 1080. Cable and satellite systmes can be in either, and nobody broadcasts 4K on air...yet.
All of those numbers dwarf what came before it, "Standard Definition" (SD).
In the golden days of television (before 2009), TV sets used electron beams to draw "raster" lines on phosphors in a picture tube. That was standardized way back in the 1950s at 525 lines in the US. Some of those lines were used to communicate sync, time code and eventually closed captioning, so you wound up with only 480 raster lines of picture information. And when they transitioned to digital TV in standard definition, they converted those 480 lines to 480 rows of pixels. If you see something is in “480i” it’s SD.
To show an SD picture on an HD set, the set or the player has to “interpolate” the pixels – which is a fancy word for blowing them up so they fill the screen, taking guesses as to how the picture should be reconstructed - 30 times a second. Unlike what you see on TV crime shows when they zoom into a license plate to catch the bad guy, it’s physically impossible to convert an SD image into a clear HD image. Some TVs do a pretty good job of interpolation, as long as you don’t look too closely.
Since VHS tape is Standard Definition to start with, the digital transfers of VHS are always in SD, which is bad enough. But then we have to look at the quality of camera and recording medium itself.
Pro vs. Consumer Cameras
Broadcast cameras, like those used for Johnny Carson, could deliver a very robust analog signal, and they’d look great on tube-type TVs that could only show 480 lines. Those cameras cost hundreds of thousands. But home movies on VHS were shot on small units with primitive cameras and cheap lenses, so the signal going to the tape was not broadcast quality. We see flares with bright lights, extended grain when underexposed, and other artifacts that are just going to be amplified when shown on HD.
Tape Format Issues
The sharpness of an analog signal with 480 raster lines depended on the frequency of the signal being recorded. Broadcast videotape set the standard, again with machines costing hundreds of thousands of dollars, but to miniaturize the process, it took a lot of electronic trickery to squeeze video into those VHS cassettes. At full speed SP mode of standard VHS, you got about half the quality of broadcast. Then they slowed the tape down even more to make LP (4 hour) and SLP (6 hour) modes possible - at the cost of even lower quality. The artifacts are blocky, blurry video with colors that shift. When blown up across a modern flat screen, it's just not pretty.
Suppose you put two VHS decks together and started editing. Rather than splicing like you could with real movie film, video editing was a copying process, and every time you copy an analog signal, you get “generation loss.” The resolution decreases and artifacts compound, and before you know it the tape is a garbled mess. Blow that across a 4K screen, and you’re really in trouble.
And that's not to mention the other issues we run into, like recording when the heads were dirty, or a camcorder that had fallen out of adjustment. We've also encountered "sticky shed," where the tape itself has degraded from exposure to moisture and it gunks up the player, making the playback warble, skip, drop out, and even stop (though that can be cured - see here).
Maybe you were smart and used Betamax, or Sony's 8mm/Hi-8mm format. Those formats are marginally better, but they're still locked in SD land, and have much the same problems - especially if copied.
So what to do?
Despite all that, your family memories are locked on VHS and you want to make them viewable on a modern system. That's why Advent Digitizing can digitize them to DVD or digital files on a flash drive, preserving as much quality as possible. Because your VHS transfers are not going to look like 4K video from your iPhone on your big new flat screen, here are some viewing tips:
- Not surprisingly, the best way to watch VHS that’s been transferred to is to put it on DVD and watch on a legacy tube-type TV with a set-top DVD player that can connect to it. The pictures will look just like the tape because that's what DVD was designed for. Unfortunately, if we transfer just to digital files, I know of no way to connect a computer to an old-fashioned TV anymore. And DVD and even BluRay is soon to be obsolete.
- Obviously you can view the files on a computer screen. To see them clearly, don't run them full screen. Size the window down and you’ll find a place where you’re seeing about 480 lines and the video will look fairly sharp. Enjoy it there.
- If you’re watching on a flat screen TV set that doesn’t offer the ability to watch in a window, sit far away from the TV. Your eyes will interpolate and it’ll look sharper than it does close up.
Bottom line, when you are wondering how to convert VHS to digital, keep all this in mind to set your expectations realistically. The precious memories are still there, they just will never be in HD.
Where to go?
Are you asking where to transfer VHS to digital files or DVD? You need someone with the gear and experience to capture all the quality of your VHS without losing any more. At Advent Digitizing we do unique things not found at the "box" transfer shops.
- First we time-base correct all our transfers to get the most stable picture possible.
- Second, we can "bake" tapes that exhibit sticky-shed.
- Third, all our transfers are made to the digital camera quality “DV” format at 25Mbps – the same as if you filmed it with a professional DVCAM camcorder. These are huge files without heavy video compression, and you can use them to edit the footage or make DVDs. But we also then transcode the footage to the MP4 format, which is the format currently used by YouTube. Those files can be shared or streamed on your computer or media player devices because the file sizes are manageable. If you want both, all it takes is extra storage.
- Finally, if your tape is shorter, we charge less! Why should you pay the same for a 6 hour tape if you have only 30 minutes of program?
Trust your precious tapes to Advent Digitizing. You’ll be glad you did.
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