[vcf-midatlantic] Laserdisk transfer to digital?

David Ryskalczyk david.rysk at gmail.com
Mon Jun 21 23:40:20 UTC 2021


> Of course it is out of reach for people like me who don’t have the hardware or the money to spend on something like this.

I should have mentioned: some people are using inexpensive Conexant TV AV capture boards which have a hidden "raw ADC" capture mode, but still have most of the all the capabilities of the more expensive Duplicator hardware. (driver at https://github.com/happycube/cxadc-linux3 <https://github.com/happycube/cxadc-linux3>) And others are working on improving TBC-based methods as well. So if you're doing any sort of analog capture, it might still be worth checking out the work in their Discord.


David



> On Jun 21, 2021, at 6:10 PM, Sentrytv <sentrytv at yahoo.com> wrote:
> 
> I’m glad that you sent out this email which made it much more clear to people like me, who needed this explanation.
> 
> Of course it is out of reach for people like me who don’t have the hardware or the money to spend on something like this.
> 
> I will stick to S-Video and TBC for now!
> 
> Mike 
> 
> 
> Sent from:
> My extremely complicated, hand held electronic device.
> 
>> On Jun 21, 2021, at 4:56 PM, David Ryskalczyk via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>> 
>> I'll try to address a whole bunch of emails together here:
>> 
>>>> On Jun 21, 2021, at 4:24 PM, Ethan O'Toole via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org <mailto:vcf-midatlantic at lists.vcfed.org>> wrote:
>>> 
>>> BUT... the discs I have are 3M branded "blank" laserdiscs that are not in a cart, they work in a normal consumer laser disc machine. The video on them is surgeries, some kind of doctor training. It looks like the 3M silver floppy disc boxes, but it's just a cardboard sleeve with the recorded disc inside, no caddy.
>> 
>> The Domesday Duplicator folks are very interested in getting any discs of this nature preserved! There are people on the Discord who watch eBay for such discs, to buy them to preserve them. Often such discs sell for way too much.
>> 
>>> On Jun 21, 2021, at 2:21 PM, Wil Birkmaier wrote:
>>> I had forgotten about this! I think there was some talk about using this for MAME or something to allow full emulation of Dragon's Lair and other FMV games from the arcades.
>> 
>> I believe that much of this media has already been captured, and work is being done to figure out the best way to handle these 50GB-per-side captures — just directly adding them to MAME would be problematic, in part due to size and in part due to the processing requirements of the ld-decode software!
>> 
>>> On Jun 21, 2021, at 11:21 AM, Matt Patoray via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org <mailto:vcf-midatlantic at lists.vcfed.org>> wrote:
>>> For digitizing they video nothing is better than a “broadcast quality” transcoder/TBC, running composite out of the player is the best option since LaserDisc is a composite video format and any conversion to S-Video would be late 80’s-early 90’s consumer grade. 
>> 
>> The Domesday Duplicator method is more akin to using a flux-level imager for floppy disks. It does not involve any conversion to S-Video or any other format. Instead, the signal is captured as close to the laser as possible, bypassing nearly all the filtering/processing circuitry in the player. After this archival capture is made, the data can then be processed in software using ld-decode (https://github.com/happycube/ld-decode <https://github.com/happycube/ld-decode>), which is an open-source software-defined LD decoder. Sufficient oversampling is used to capture the best signal possible, but even so, multiple captures of different "copies" of the same disc pressing can be "stacked" to obtain better results. https://mastodon.online/@simoni/104874150717929190 <https://mastodon.online/@simoni/104874150717929190> shows an example of what stacking can do.
>> 
>> Software decoding of the RF directly from the laser also allows for advanced recovery techniques such as dropout correction, and allow for the direct capture of chapter markers, frame numbers, and digital audio.
>> 
>> The Acorn and BBC Micro User Group had two fairly detailed presentations with the project leads here:
>> http://abug.org.uk/index.php/2020/07/04/domesday-86-part-1-the-project/ <http://abug.org.uk/index.php/2020/07/04/domesday-86-part-1-the-project/> (hardware)
>> http://abug.org.uk/index.php/2020/08/01/domesday-86-part-2-ld-decode-simon-inns-chad-page/ <http://abug.org.uk/index.php/2020/08/01/domesday-86-part-2-ld-decode-simon-inns-chad-page/> (software)
>> 
>> No matter what method is being used, having a calibrated player turns out to be important. Calibration requires the GGV1069 disc, and procedures that don't requite custom tools can be found at https://www.domesday86.com/?page_id=2896 <https://www.domesday86.com/?page_id=2896>.
>> 
>> 
>> Overall, I would expect a Domesday Duplicator setup to require the following (in addition to electronics tools to perform the calibration and tap the RF):
>> 
>> Working LD player (most will work, certain models are preferred based on reliability and calibration)
>> GGV1069 calibration disc (around $100)
>> Domesday Duplicators, consisting of an Altera DE0-Nano board, Cypress FX3 board, and the Domesday Duplicator board — people have been putting these together for around $300-$500
>> 
>> A computer to capture the data — USB 3.0 and 16GB of RAM is probably enough
>> A computer to process the data — this can be done offline, after the fact
>> 
>> As the Domesday Duplicator captures the RF signal before it is processed by the LaserDisc player, the player would have to be slightly modified to tap the RF.
>> 
>>> On Jun 21, 2021, at 3:45 PM, Sentrytv via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org <mailto:vcf-midatlantic at lists.vcfed.org>> wrote:
>>> As usual, there is a complicated answer and way to do things and there is a simple answer and way to do things.
>> 
>> In this case the process for LaserDisc has been very much refined, and the folks over at the Discord channel provide lots of help. So even though it might be more complicated to get started, there is plenty of support available and long term the results are much better. That said, it might not be worth the trouble for a handful of discs if someone already has a full setup!
>> 
>> 
>> 
>> This method is being extended to VHS and other tape, with some rather impressive results — See e.g. the videos on this YouTube channel for some VHS examples: https://www.youtube.com/user/swilwerth/videos <https://www.youtube.com/user/swilwerth/videos>
>> Do note however: the process for tape is nowhere near as refined and much more experimental, compared to LaserDisc!
>> 
>> David
>> 
>>> On Jun 21, 2021, at 4:24 PM, Ethan O'Toole via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
>>> 
>>> 
>>> 
>>> Woah! He has one! I remember seeing one of those at a NASA auction.
>>> 
>>> BUT... the discs I have are 3M branded "blank" laserdiscs that are not in a cart, they work in a normal consumer laser disc machine. The video on them is surgeries, some kind of doctor training. It looks like the 3M silver floppy disc boxes, but it's just a cardboard sleeve with the recorded disc inside, no caddy.
>>> 
>>>       - Ethan
>>> 
>>>> Like this: https://www.youtube.com/watch?v=KQ-yIsrOUU8
>>>> 
>>>> On 6/21/21, 4:08 PM, "vcf-midatlantic on behalf of Ethan O'Toole via vcf-midatlantic" <vcf-midatlantic-bounces at lists.vcfed.org on behalf of vcf-midatlantic at lists.vcfed.org> wrote:
>>>> 
>>>> 
>>>> Are the training laserdiscs pressed at a factory or are they the ones
>>>> recorded in a LD-R or whatever the DIY laser disc recorder machine was
>>>> called?
>>>> 
>>>> I have a few that were recorded on one of those DIY machines, neat
>>>> conversation peice. I think they're 3M. Look like giant floppy disc box on
>>>> the front :-)
>>>> 
>>>>              - Ethan
>>>> 
>>>> 
>>>> 
>> 
> 



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