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| drecksoft |
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Posted: 29 Jun 2021, 14:12
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I came into this forum to basically post this exact thread.
I was hoping to find some information on the AC3 RF signal. Like the frequency it operates on, etc.
I'm an embedded firmware developer, and I wanted to look into building my own demodulator with a few cheap parts like say an AVR (Not sure if they're fast enough -- might need to go ARM) plus some RF and SPDIF modules. The problem is I just can't seem to find the required technical documentation on the AC3 RF signal itself.
In theory, I should be able to convert the RF signal into a bitstream and send it out over SPDIF relatively easily. In theory. I'll see if theory matches up with reality if I can get my hands on specs. :lol:
If I'm able to come up with a solution, I'd be happy to share the information and even source code with others who could build their own. Hopefully with just a dirt-cheap Arduino board and a couple other bits. I could utterly fail, as RF isn't one of my areas of expertise, but I'd at least like to give it a try.
$200+ on eBay just to get AC3 surround from a Laserdisc is insane.
I'm wondering if the details are too well-kept of a secret to pull this off.
If you find anything about "software decoding" AC3-RF that would also be very helpful for ld-decode. See: https://github.com/happycube/ld-decode/issues/622 |
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| drecksoft |
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Posted: 21 Jul 2021, 19:20
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| Just wanna say thanks for the instructions. I replaced C116 on a dead DVL-919 and temporarily bridged the blown P612 and it works again. I now ordered new fuses then hopefully everything will be OK again. |
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| drecksoft |
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Posted: 08 Nov 2022, 22:37
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el.pablo wrote: Does anyone have one to sell or know where I can get one? Thanks.
In the US? Not anymore. I saw one on ebay Kleinanzeigen in Germany. |
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| drecksoft |
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Posted: 09 Jan 2023, 11:59
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I found something interesting I couldn't find any information for.
Fitto Karaoke Boxes
I got two filled with various Hong Kong Karaoke discs (not only from Fitto). I don't know if those came pre-filled or could be bought separately. One came with a catalog / song list for Fitto LAV 8001 to 8030.
IMG_3164S.JPG
IMG_3163S.JPG |
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| drecksoft |
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Posted: 25 Mar 2023, 21:43
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That's not so uncommon.
Werner - Beinhart! (1990) [51397]
The first comment says, there is a second cover version. That's correct, I do have both. And this is not the only one. |
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| drecksoft |
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Posted: 27 Mar 2023, 20:59
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There are even worse things: Same cover, same catalog number but one version in full screen, one in widescreen. So different content here. The ONLY difference is a sticker on the later one.
Lethal Weapon (1987) [11709 LD]
Or here where there are two covers but to know if you have the "fixed" version of the disc, you have to look at the mint marks.
Eagles: Hell Freezes Over (1994) [ID4065GF] |
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| drecksoft |
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Posted: 06 Oct 2023, 14:54
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I had another look at the player and there are more adjustment points. I slightly increased some of the potentiometers and now have a decent image. I could also revert the three settings i previously changed to get a picture to their original state. So nothing is maxed out now.
Sound is also there now.
I don't know how good the image should look. I get some shadows on the Japanese subs but it is still a old analog medium not a Blu-Ray.
It's absolutely worth not giving up on such a well-build machine. It'll go back to storage now nevertheless. I won't keep the setup for just one disc. |
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| drecksoft |
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Posted: 13 Oct 2023, 07:56
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| drecksoft |
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Posted: 18 Feb 2024, 11:57
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It's a shame @laserdisc.ws doesn't want to provide any pictures or information. Such a rare piece should be shared with the community.
I was also following the various auctions on HD MAC and other rare discs but I won't spent a few hundred $ just to have such an item without a player. |
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| drecksoft |
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Posted: 04 Jun 2024, 12:10
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| It's a nice piece of technology but my LVR-6000 & LVS-6000P has been packed away after one test. Yeah, they are working (at least the playback, haven't tried recording) but other than being curious about it once there is not much use for it unless you have some disc you desperately want to play. |
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| drecksoft |
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Posted: 15 Sep 2024, 09:06
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I doubt that the Toshiba HD-E1KY can output DTS-HD MA and TrueHD bitstream over HDMI. This is a first gen player and the basic model. It should even have only HDMI 1.2, not 1.3
Only the higher end models could output the bitstream. Toshiba even locked out the EP30 from DD/DD+ bitstreaming even though the hardware was capable of it (no DTS-HD MA bitstream capability though).
LG BH 200 should do bitstream on later firmwares. |
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| drecksoft |
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Posted: 31 Dec 2024, 10:43
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Do you have any dropouts in the picture too? It could also be rotted discs but shouldn't be the case for all of them.
If you select analog audio on a disc with AC3 you will get one channel of noise. You then need to select analog left only, not stereo. |
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| drecksoft |
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Posted: 01 Jan 2025, 10:30
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| Other LD remotes SHOULD work, CD or DVD remotes MIGHT offer some basic functionality but likely switching audio is a specific function. You can try universal remotes, preferably older ones. |
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| drecksoft |
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Posted: 16 Jan 2025, 20:35
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There seem to be quite a few different releases with different content.
There are the (at least to me) most common versions from Software Corner
Dragon's Lair [SC 426020-1]
Thayer's Quest [SC 426020-2]
Mine came together in a box:
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With an additional picture:
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The box has room for much more, so maybe some extras are missing.
Then there are two RDI discs but it is unclear where are the differences.
590-0002 has a metal plate on the dead side. Likely for an arcade machine. Never seen a 590-0001.
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Then there is a two sided release that starts with Halcyon and RDI logos.
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_DSC7790S.JPG
The two labels are slightly different. I think, the content is the same but the sides are reversed between the two discs. I've only done a short check.
So far I haven't found any other Dragon's Lair discs.
Does anyone know more about the different Thayer's Quest versions? |
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| drecksoft |
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Posted: 23 Jan 2025, 17:26
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The rot status is completely unreliable in general. You only have a slight indicator on popular titles. For example all German and most UK rotters are listed with none or (very) low probability, even on titles where you have a 90% rot chance. Yeah, I myself only reported one rot status so no judgement here.
The other way round (like with Star Wars) is also true. High Probability does not mean most discs are gone. I think a lot report some dirt on the film print as rot or chroma noise as rot and so on. Also a speckle here and then can be caused by anything, not necessarily rot.
Maybe the rot level should be taken into account? A dead disc counts like 10 times a light rot? But that might lead to awfully complex calculations. |
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| drecksoft |
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Posted: 12 Mar 2025, 07:22
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Good luck finding one in that price range. That will sell in minutes.
No you can't use just any 8" CAV disc. You need the specific test patterns. |
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| drecksoft |
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Posted: 15 Mar 2025, 09:18
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The Panasonic UB820/824 UB9000/9004 can be region free, UOP/PUO off and several other things with a patched firmware. So I'd say currently the best choice. I don't see any reason for the overpriced UB9000.
https://www.avforums.com/threads/lets-try-again-to-put-the-free-in-regionfreedom.2441584 |
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| drecksoft |
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Posted: 22 Mar 2025, 17:08
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This was a "user too stupid" issue.
One of the replaced capacitors DID fix the issue. However, I needed to put the PSU back into the player cause even it has a physical switch, it will only enable the 5V if the front panel is connected. |
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| drecksoft |
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Posted: 27 Apr 2025, 13:01
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Plextor had a special mode in some of their CD burners to fit more data on the CDs. So the pitch length of those devices is adjustable in some way.
But judging by the specifications and tolerance a "regular" CD burner should work. We "just" need to create a raw format iso with the LD data. |
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| drecksoft |
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Posted: 28 Apr 2025, 14:03
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We "just" need to create a raw format iso with the LD data. Ah yes, the dreaded "just". Just hand that Toyota to me, OK? :)
Since the variable-length pits in the track do not correspond to digital data in any way (8-bit, 32-bit, or whatever, all data bits are of identical length within any optical disc format), we would need to create some kind of conversion algorithm such that a "digital 17" equates to an instruction to burn a pit 17 micrometers long (or 0.17 uM, or whatever is appropriate) as opposed to burning "digital 17" itself into the disc, which is 00010001 in 8-bit digital.
Also, the burner drive would have to work at 10X-12X the normal CD data speed at a minimum. How do we know this? CDs play at "1X", which is 200 RPM at their outermost point. CD Video discs play at 1800 RPM at the same point if I remember right, and 2700 RPM at the beginning of the five-minute analog content area. So, we need to burn at least as fast as the discs are read. CD-ROM drives went up to 52X if I remember right, but I forgot how fast burners are/were. An 8X DVD burner may be plenty fast, strictly considering burning-hardware speed.
Fun stuff for keeping otherwise-idle brains sharp.
No, we could burn at a slower speed as long as the data is correct. However, there were burners up to 56x speed. Most were limited to 48x. Still more than enough.
The first step would be to read a CDV in a CD drive though. This is already hard enough. The TOC the CD drive can read only shows the CDDA tracks. All software i know of just stops at that point. Some can "overread" into the lead-out but we would need to read PAST the lead-out to get the LD "data". I assume there is a separate TOC for the LD part somewhere but of course that is not recognized by the CD drive.
I'm not sure if there were protection mechanisms on CD games with manipulated TOC indicating less data than actually on the CD. Then some old copy protection bypassing burner software might read something. But I'm only aware of manipulated file sizes in the CD file system so that if you would do a file copy you would end up with Gigabytes of data. |
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Thanks list