VHS: external A/D vs. capture device?

[jonfullmer]

Quest: To digitally convert a few hundred NTSC VHS tapes, ideally uncompressed

Analog Equipment: I have a VCR (Toshiba) and an AVTool AVT-8710 TBC

History: I've used several different capture devices in the past (many years). Most recently, I'd been using a BlackMagic Intensity Shuttle (USB 3.0) and a MacBook Pro (2019 16"). It would seem that upgrading the MBP to Big Sur has made the Shuttle useless to me (though I'm still waiting for the official word from BlackMagic).

Intended Destination: I'd like to keep the raw capture as an archive. Most likely, I'll make an additional compressed copy in H.264 MP4 for general consumption.

'Plan A' Question: I came across a Startech VID2HDCON2 device. I'm wondering if I might have an easier time doing VHS conversion by having an external appliance handle the Analog-to-Digital conversion, and then using an HDMI capture device. What would be the unseen "gotchas" in this approach?

'Plan B' Question: In reading other forum posts, compelling cases have been made that, if you want to transfer analog video, Mac is not the best platform. I still prefer Mac for most of my other tasks, so a potential Plan B would be to purchase a PC with the specific purpose for transferring video. If I were to buy a PC specifically for this purpose (transferring VHS), what specs/cards/OS/devices would you recommend?

Bear in mind that I have no aspirations to capture any video other than analog. Also, I've used Windows since the the 3.x days (through to Windows 10; even used ME, briefly). I've been a Mac user since System 6, and I've been a Linux user (various distributions) for almost two decades. I prefer Mac for general use and Linux for servers. I'm open to whatever may work best for this scenario.

Conclusion: Thank you in advance for any help and feedback. I really appreciate your patience and expertise.

[cygnals]

If you're shopping at Startech, the USB3HDCAP does composite and S-Video in addition to HDMI. I've been using it with Virtualdub for lossless capture and it's been working great.

[jonfullmer]

Thanks, cygnals. But alas, there's only Windows support (unless you know of something that's changed). Any recommendations on a PC setup?

[jonfullmer]

Sadly, I found one "gotcha" with Plan A that I hadn't thought about: aspect ratio. With the VID2HDCON2, if it's fed a 4:3 video, it will be stretched. That's a show-stopper.

[latreche34]

Your options are very limited under iOS, Under Win 10 is going to be a giant rabbit hole, Get a used desktop or laptop with Wind 7. Specs? people captured under PentiumIII, So I assume a single mom average dell computer from 2010's with 1.8GHz and 1 Gig of RAM should do the trick.

[jonfullmer]

Thanks, latreche34. I was thinking something along that line. Just needed confirmation.

I did confirm that BlackMagic Design stopped supporting the USB3 Intensity Shuttle. For a five year old functional device, I'm pretty disappointed in that. I can boot my MBP to MacOS 10.15 (Catalina), and it will work, but what a nuisance.

Plan B is looking imminent.

[Hushpower]

Quote:

Sadly, I found one "gotcha" with Plan A that I hadn't thought about: aspect ratio. With the VID2HDCON2, if it's fed a 4:3 video, it will be stretched. That's a show-stopper.

Correcting the aspect ratio is pretty basic; I would have thought a Mac video editing program could do that easily.

[traal]

The VID2HDCON2 upscales to 720p, losing detail and/or adding sharpness artifacts. It also deinterlaces, something it almost certainly doesn't do as well as QTGMC/IVTC and a human deciding which one to use based on content.

[jonfullmer]

I know the aspect ratio can be corrected after, but that's...after. I'm trying to archive this video, and I'd rather not capture it stretched. I'm sure we can appreciate the difference between "capturing 4:3 video" and "capturing 4:3 video that's been stretched to 16:9 and then corrected back to 4:3", right?

[dpalomaki]

Analog SD video, such as is on VHS, is an interlaced raster scan. The image is comprised of (for NTSC) 486 scan lines with about 52 microseconds of varying voltage that corresponds to the image (brightness and color).

To preserve the image in a digital form one will need to digitize the scan lines with sufficiently high sampling rate and sample depth to be able to recreate each scan line's voltage (wave forms) with sufficient accuracy.

Because the top and bottom few scan lines and line ends contain little if any useful image (a legacy of overscan standards) there is no reason to archive (NTSC SD) to a format other than the standard 480 lines. More than 480 (or 486) lines can add up-scaling artifacts, less than 480 loses data.

Because the analog SD video signal was bandwidth limited (maximum frequency image information present in the scan line analog signal on VHS is around 3.5 mHz at best, (anything present above that is likely noise) there little reason to sample the scanline much above say a 7 mHz rate. (Broadcast air signal, Hi8/S-VHS, and live cameras can do perhaps 2x better.) 8-bit sample depth gives a dynamic range of 48 dB, better than the signal-to-noise ratio of the common analog formats.

This has lead to the standard SD digital video being 480 lines of 704 pixels (non square pixels) with an 8- or 10-bit sampling at 13.5 mHz. Use a lossless, widely available, non-proprietary codec for archiving to ensure future access. Make resolution changes to the distribution copies.

The "stretching" of the image is a matter of how the display interprets the pixel aspect ratio. The pixel count (per line) and bit depth determine how accurately the scan line waveforms can be reproduced. 640x480 is adequate to accurately represent a VHS signal, but 720 (704) x 486 (480) is better and a digital video standard.

[jonfullmer]

Thanks, dpalomaki! Great discussion!

I knew that the digital video standard was 720x480 (same resolution for an SD DVD). That was the problem I discovered with the VID2HDCON2. It would take the 720x480 input (~4:3) and stretch it to 720p (1280x720; 16:9). No likey.

Do you mind if we talk a little more about this sentence:

Quote:

Use a lossless, widely available, non-proprietary codec for archiving to ensure future access.

Using the Intensity Shuttle (back when I could), I used QuickTime Uncompressed 10-bit YUV and eventually ProRes 422 for the archival copy. I recognize that both are proprietary to Apple.

I realize this might be insane, but I have several old Dell PowerEdge servers. In particular, I have an r710 that I could add a USB3 card to. BlackMagic does provide a Linux version of their software (supports Ubuntu 20.04, CentOS 7-8, etc.). I may be able to continue to use the Shuttle that way. Worst case, I might be able to install XP or Win7 on it (though their forums have complaints of driver recognition on the Windows side, too).

My point is that using QT/MOV on a Mac is admittedly convenient, but it's a little more of a pain to do on any other OS (Windows: mild; Linux: major). I know my audio codecs pretty well, but what lossless non-proprietary video codec would you recommend? Again, this would be for archival.

Thanks again for your help!

[dpalomaki]

Apple is a closed system, fewer options. Windows is more open, more options, more widely supported, lower cost - and often requires more thought on the part of users to setup and operate systems.

Others here are better positioned to recommend specific codecs for archiving; I've not done any serious examination of that subject. There are many threads on the subject.

Points to consider are the required life of the archive, who will maintain the archive once you leave the scene, and the consequences if it becomes an orphaned format? As long as someone competent is monitoring the archive to ensure the data does not decay, and to losslessly recode and rearchive as technology changes during the intended life of the archive you will have more options.

If no one else seriously cares, it may not matter much how you do it as long as you are content with the result.

An interesting point on archived information. Difficult to find a place to read an 8" or 5 1/4, or 3.5" floppy disc these days, or an 8-track cartridge audio tape. But I can still read books published hundreds of years go, and readily find gear to play 78 rpm records. Not sure I could open and read a MultiMate or Enable file if I received one.

{Well, maybe fire up an old PC with DOS 5, install an old version of Word or Word Perfect and try open it.}