Trouble Opening, Converting Old Video "AVSEQ01.DAT"

[DB83]

With the greatest respect to your father, he really should have realised that a slide-scan to VCD would not have retained the definition of the original scan.

I 'dabbled' with slide scanning more years ago than I care to admit to. Yet the resultant slide-show video was more than acceptable way back then.


I still have the original hardware/software which cost more than a pretty penny back then. So if you are curious/interested I would be more than willing to fire this up again to show what is achievable and not cost you a fortune in hardware. Just write off the 20 bucks you paid for the VCD to {whatever} to 'experience' the reality. Just PM me in due course. (Of course I am sure that more local services will offer the same)

[Cornucopia]

Yeah, 35mm slides have a resolution when scanned of ~4000x3000 pixels, varying greatly depending on source, scan equipment, method of scanning, aspect ratio, etc.

VCD "stills" are capable of only full D1 SD resolution (704x480 NTSC or 704x576 PAL).
Standard VCD video tracks are only capable of 352x240 NTSC or 352x288 PAL. Even if the video is of stills.
Considering back when VCDs were popular, it was even then a rarity that users were savvy enough to properly create VCD stills (there were a number of threads on this site that went into it, where I was a contributor).
So, unfortunately, I doubt that the original transfer was able to take advantage of that, and that likely means your quality loss is over 100x (over 10x in each direction). Even if that is an overestimate, the loss is going to be quite noticeable.

BTW, DVD stills are no better than VCD stills, and just as difficult to create.

Easiest thing these days is to just create very high quality JPG or PNG, etc files and use a media player that supports playing them via whatever medium you decide to put them on. So, my recommendation, IF YOU STILL HAVE THE ORIGINAL SLIDES, is to rescan to high rez still picture files.


BTW, if you decide not to do that, jagabo's ffmpeg remux suggestion is really the ONLY good way to get from DAT --> MOV --> MP4 without incurring loss, on a (modern) Mac. While Quicktime purports to support MPEG1 and has listed that as a supported format since v2.x days in the '90s, the reality is that while the QT7 player "played" MPGs, it didn't play them from within MOV tracks, but using a separate plugin that only dealt with external MPEG streams (and often wouldn't pass through audio). Because the MPEG is a pre-multiplexed stream, QT wouldn't normally recognize it as a video or audio track, without that plugin. And that was QT7, a 32bit app which since Catalina is no longer supported. And, unless I'm mistaken - somebody give me a reference to contradict please - QT10.x player (and the underlying AVfoundation) doesn't appear to support that MPEG1 plugin, so native Apple support of MPEG1 appears to be dead in the water for newer Macs. Yes, the MOV file format supports multiple tracks and track types, but support for multiplexing, and especially pre-multiplexed tracks, doesn't equate to support for native playback. Even their long support for DV has always been plagued with hiccups and bugs (don't get me started - I have a couple past posts specifically about QT and DV on this site).

It is only by virtue of the flexibility of the completely 3rd party open source alternate architecture of ffmpeg that allows the conversion.
It is hard to say whether the Mireth app you mention does remuxing, though from the site documentation I highly doubt it. And reconversion (and accompanying lossy recompression) adds further quality loss, independent of the existing resolution loss issue. Is it Mireth based on QT code? AVfoundation? their own custom code? or even perhaps as a front end for Ffmpeg?

Scott

[jagabo]

I didn't realize the Mac's support of MPEG1 was so poor (or non-existent).

By the way, one can convert the DAT directly to h.264/aac in MP4 with ffmpeg:

ffmpeg -i source.dat reencode.mov

The defaults when encoding to MP4 are h.264 and aac. x264 is used at the default settings (medium preset, crf=23). I would recommend higher quality than that by specifying -crf 18 or so.

And yes , rescanning the slides is the best option.

[MEsk]

Excellent insights all, (ladies and) gentlemen. My Dad was a competent photographer and certainly appreciated a sharp, well-composed shot. In his retirement, though, I think he was so intent on converting his slides into a broadly accessible format (ha!) that he was willing to make the quality trade-off to VCD. Now that I've got the VCDs operating and have had a good look at what's stored there, there's no question...THE SLIDES MUST ALL BE RESCANNED. There's no comparison between the VCD pics and the originals. The detail loss just isn't acceptable. Remember Kodak carousel trays? There are 25-30 sitting in their boxes on my office floor. If I were a slouch, I'd rip off copies of my new MOVs, send them to family by the dozens, and call it good But I won't. Time to dust off the old scanner and put it to work.

...which brings up a whole new topic...the best way to archive digital AV files, for the LONG haul. As Arnie said, I'll be back

[lingyi]

...which brings up a whole new topic...the best way to archive digital AV files, for the LONG haul. As Arnie said, I'll be back

Only one way. Multiple copies, ideally with at least one set kept offsite in case a local catastrophe takes everything out. https://www.backblaze.com/blog/the-3-2-1-backup-strategy/#:~:text=You%20may%20have%20h...%20off%2Dsite.

What you choose to store your files on is less important than having multiple copies. n-1=0

Continually check, verify and copy to new media.

Digital is the only medium that can theoretically be perfectly duplicated ad infinitum.

[Cornucopia]

Yup. Expect a protracted schedule of periodic data migration with checksum verification.
Use media types that will expect to be recoverable/usable/readable in 5-10-15 years. This also means supporting players/readers must also be available.

Scott

[MEsk]

Did I see the admonishment "supporting players/readers" must also be available? Hmmm

lingyi: Thankfully, I was following your archiving advice last year when I began copying jpgs on to SansDisk flash drives, then sending them out to family members far and wide. Safety in numbers. You've reminded me I need to put one of those flash drives in a safety deposit box. Thanks. I've got some confidence moving ahead.

[lingyi]

Computer optical drives are sold in the tens or hundreds of millions and will be available for decades to come, probably at least our lifetime even for preteens. Yes, their mechanics may fail, but your data should be moved to new media well before then anyway. Older hard drive technology (MFM and RLL) interfaces are hard to come by today, but IDE is still available and SATA will be around for decades also. Again, all hardware availability is moot because data should be migrated to new and multiple media anyway.

Flash drives, SD cards and SSDs are not archival. Flash drives and SSDs MAY lose data when left unpowered for long periods of time, months or years. SD cards are meant for temporary use.

The bigger issue with all of these are that when they fail, they tend to fail all at once completely. And data recovery, which should never be a necessary option because you have backups, is extremely expensive, $$$$ and iffy at best.

In addition, they're multiple times more expensive per TB than HDDs.

Optical discs are an option, but again are multiple times more expensive per TB than HDDs and potentially cost effective up to low tens of TBs.

LTO can be cheaper and long lasting, up to 30 years, but the hardware cost is moderately expensive, $$$ for older drives like LTO-5 and outrageously expensive $$$$+ for LTO-8 and LTO-9

[MEsk]

For working storage, I use a WD external HDD, which has been cost effective. But purchasing flash drives in half-dozen batches as copies for others has been pricey. So...am I understanding that it's back to CDs or DVDs again for AV sharing/archiving, because they're: 1) less expensive, 2) potentially longer lived, and 3) less susceptible to wonky data loss than flash? CDs or DVDs, at least, for my FIRST mode of storage and dissemination, since one should juggle storage methods over time. (...just tripped on University Products for sleeving, etc.)