LaserDisc Database
https://forum.lddb.com/

(WIP) Laserdisc software image decoder from raw signal
https://forum.lddb.com/viewtopic.php?f=32&t=2671		 Page 30 of 31
Author:  laserdisc.ws [ 22 Oct 2021, 03:58 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Forgot to ask: how many GBs is a raw captured per hour - more or less?
Author:  smally_uk [ 22 Oct 2021, 09:41 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
laserdisc.ws wrote:
Yep, my bad - I was thinking about the fact it has three video outputs, but one of them is RGB! :angel:

The RGB decoding on the 4300 is pretty bad with an analogue comb filter and is very basic.

laserdisc.ws wrote:
Sure a MUSE player with its red laser could in theory grab more info - in particular with laser rot discs; still, even if I was an experienced welder (and I'm not) I would think not twice, but dozen times, to open up a MUSE player to mod it! :shock:


There have been a few people with X9/X0 players moded and the results are a bit hit and miss.
Due to the different wavelength of the laser they are better at reading rot as you said but also with the smaller dot on the surface of the disc there is also less crosstalk. The downside to this is that it it much harder to calibrate as you can only truly calibrate the MUSE players with a MUSE calibration disc which will cost you more than an X9 anyway...
One of the moded players is in Japan and was recently serviced by Pioneer and still has difficulties playing some discs (I dont think they have the experts there any more)

If you are looking to capture rotted discs the best bet is do what we did with the BBC Domesday discs and just capture lots of them in calibrated players and then stack the results.
With a stack of 7 very rotted discs we have a signal to noise ratio better than what you could get with a MUSE player anyway AND.... there are no dropouts in the final result. Obviously if you captured 7 copies in a muse player you will probably get better results but one of out tactics is to capture the same disc in multiple calibrated players if at all possible. This removes the player from the equation.

laserdisc.ws wrote:
Forgot to ask: how many GBs is a raw captured per hour - more or less?


If you capture with the Domesday Duplicator you are looking at 180GB/hr for the capture but this can be then compressed down to 75-90GB
Author:  laserdisc.ws [ 22 Oct 2021, 10:55 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Thanks for the reply!

180GB is quite a lot, as well as 75-90GB - normal capture with HuffYUV is around 10GB/hour.

Stacking: I used this method with one of my project, and result was great - even with "only" three captures, dropouts were gone, and resolution improved a bit. I guess using the stacking method with both raw and normal capture would decrease the difference between them, in particular using so many discs and/or players, and using better players for normal capture Vs. LD-V4300D.
Author:  smally_uk [ 22 Oct 2021, 11:47 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Stacking with Laserdiscs is fully automated and can deal with frame drops as well as dropouts.
This is due to when the RF is lost due to a dropout it is automatically flagged through the entire toolchain. When stacking it does the median of the values but only where they are not dropouts.
It can also do differential dropout detection so if you have more copies then it can identify dropouts that are not detected by the RF level detection.
The automatic alignment uses the timecode and frame number that is within the VBI of the laserdisc. This information is lost when capturing using traditional methods.


Our 4300d's are in superb condition as mine had less than 200 hours on the player from new. and do actually outperform a traditional capture from the X9 on good discs.

For the 180GB / hour, that is the RF capture and not the final video output which can be in any format that ffmpg can support.
Author:  laserdisc.ws [ 22 Oct 2021, 11:49 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
smally_uk wrote:
Our 4300d's are in superb condition as mine had less than 200 hours on the player from new. and do actually outperform a traditional capture from the X9 on good discs.


:shock:
Author:  rein-o [ 22 Oct 2021, 14:28 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
laserdisc.ws wrote:
smally_uk wrote:
Our 4300d's are in superb condition as mine had less than 200 hours on the player from new. and do actually outperform a traditional capture from the X9 on good discs.


:shock:



This one made my laugh :clap: :clap: :clap:
Off to painting my house today, wish me luck, maybe it will look as clean as an old house can :crazy:
Author:  lonerangerface [ 22 Oct 2021, 14:35 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
smally_uk wrote:
If you capture with the Domesday Duplicator you are looking at 180GB/hr for the capture but this can be then compressed down to 75-90GB


When I capture LD's with the ADVC-110 and a software like Premiere Pro or WinDV, I get around 13GB/hr. Either that or it depends on the quality of the source. Anyway, for capturing US releases, I toggle the NTSC Setup Level to 7.5 IRE, whereas for capturing JP releases, I toggle to 0 IRE.
Author:  laserdisc.ws [ 22 Oct 2021, 16:59 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
smally_uk wrote:
For the 180GB / hour, that is the RF capture and not the final video output which can be in any format that ffmpg can support.


How much time would take, roughly, to decode raw capture to final video and audio tracks? I mean, are we talking about minutes or hours?
Author:  titan91 [ 20 Dec 2021, 00:07 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
I'm back for a bit. Not trying anything else with LaserDisc at the moment as I'm using vhs-decode on some tapes for a friend. That being said, I was able to borrow a few discs from someone else (Led Zeppelin concerts, etc, some barely played). The issue I had last time I tried was significant crosstalk at the end of a CLV disc, Sony's Take Two sample. Now when I first played that disc, it was warped so much that it was intermittently grazing against the top cover of my "good" player. So I flattened it with 50 pounds of books for a few weeks and immediately captured it again as soon as I took the books off.

The decoding result was more or less the same, which leads me to believe it's a laser alignment problem. The disc no longer grazes the top cover of the player when played, IIRC. So eventually I'll play a few of these other discs I just got to confirm that. If it is alignment, I'll have to painstakingly adjust the alignment pot little by little between discs (I can't access that potentiometer on my machine when playing that I know of).
Author:  cplusplus [ 21 Dec 2021, 04:04 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
titan91 wrote:
If it is alignment, I'll have to painstakingly adjust the alignment pot little by little between discs (I can't access that potentiometer on my machine when playing that I know of).

You'll need to use an 8" disc. If you are making RF captures though, you really need to check for crosstalk with test disc since this will be in the capture. Severe amounts from warp or tilt servo issues are blatantly visible, but slight amounts are hard to see without the test patterns and manifests itself as background noise that is not actually characteristic of the player.
Author:  titan91 [ 21 Dec 2021, 13:17 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
What about an audio CD and observing the eye pattern of the RF? I don't have a CD Video disc or small LaserDisc.
Author:  cplusplus [ 23 Dec 2021, 22:05 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
You should be able to set tangential looking at eye pattern, but it sounds like you are having tilt issues. The test disc gives a vertical bar pattern that moves from left, center, right across three frames. You can try seeing if you have something similar on a CAV disc.
Author:  titan91 [ 30 Jan 2022, 20:47 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Well I've got some good news, my player is fine! I captured some of Terminator 2 disc 1 side 1 chapter 28 with zero artifacts whatsoever. FM audio is also 100% perfect. This is a CLV title as well and chapter 28 is the last one on this side, the farthest out from the center of the disc. The disc also doesn't seem warped when I look at it and doesn't make any noises when spinning in the player. FLAC compressed capture and decoded MP4 are below. This is 40MPSPS 8-bit. You'll have to change the extension to .ldf to decode it.

As for that Sony sample disc, I know someone else who has the same disc. I will ask him to capture and send me his copy.

https://www.mediafire.com/file/k75vdd8s ... .flac/file
https://www.mediafire.com/file/fgsnks1p ... t.mp4/file

Image
Image
Image
Image
Author:  titan91 [ 27 May 2022, 17:54 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Has anyone tried ld-decode on an M1 Mac running Asahi Linux? I'm curious about the performance. These processors are very competitive to x86 running Mac OS. With Linux that performance is considerably better yet.
Author:  titan91 [ 06 Jun 2022, 20:42 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Here's a good analogy for impedence matching. If you're ever driving down the highway and roll down your driver side window, the air may oscillate inside the cabin. There is negative pressure drawing air in following by positive pressure pushing it out. This is a reflection of air pressure. But you if you roll down your passenger window the same amount, the oscillation stops.

The wind is the RF signal, and your driver and passenger side windows are the input and output impedence. If the resistance on both ends doesn't match, you will get oscillations (ringing) and reflections, and non-ideal voltage/pressure on the output end.
Author:  titan91 [ 20 Jul 2022, 14:53 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Harry posted these Apple CPU results a while back. Not really too different from my Ryzen 7 CPU.

Quote:
5fps - M1

6-7fps - M1 Max (top model 4TB NVME)

Observed under a Ubuntu 20.04 LTS VM
Author:  ld_out [ 06 May 2023, 17:00 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Hi everyone,

Hope you're all doing well!

I'm new here having just signed up, for reasons like many of you do :)

I didn't know where else to ask, especially since Domesday Duplicator and has been discussed by users to fabricate PCB (which unfortunately never came to fruition :( )

Although I am very new to the premise, I myself am interested in creating a board for myself for the project (and hopefully the VHS variant), but I came across the GitHub page:

https://github.com/simoninns/DomesdayDuplicator

and I just don't know where to start. There's so many files, documents, I just don't know which or what to use! :?:

I absolutely LOVE what these guys conceived and I really would like to try it out, thus I was wondering if anyone here can help me out on this matter??

Hope you don't mind me asking, I would be very grateful and appreciative too!
Author:  9954tony [ 06 May 2023, 18:55 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Welcome.

The conversation about this has mostly moved to Discord. As you can see there hasn't been much activity here. https://discord.com/channels/6655572671 ... 7189334049
Author:  ld_out [ 07 May 2023, 01:13 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
Thanks but I don't really have Discord.

Isn't there a tutorial around to instruct how to do this?

Which files do I use too?
Author:  9954tony [ 07 May 2023, 18:00 ]
Post subject:  Re: (WIP) Laserdisc software image decoder from raw signal
https://github.com/oyvindln/vhs-decode/wiki/
Page 30 of 31 All times are UTC [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/