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05-22-2019, 10:19 PM
jwillis84 jwillis84 is offline
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We've got basically all the magnavox 5xx series tested, or a sample from each yearly group tested.

This fills in some of the gaps. Basically all of the 500 series should work now. The 800 series are not being worked on at this time.. basically leading up to a Beta release, we are almost feature freeze for now.

We've got basically all the panasonics from E100H through BS785 tested and supported.

A lot of the delays with panasonics was spent establishing a baseline for what is (normal) and not corrupt. I chased a lot of red herrings.. where we thought there were code problems, but it turned out to be bugs "supported" in the Title lister for that generation of recorder. What that means is the recorder (may) seem to be listing a recording, but its corrupt or damaged on the hard drive and it simply can't be extracted in one piece because .. well.. because its not whole anymore.. regardless of what the recorder Title lister indicates. Panasonic actually did release a lot of firmware updates and a lot of bugs never got fixed.. so leaving your recordings on a HDD that got edited on regularly was a very risky proposition. They were not "kidding" when they said "get your recordings watched or burned to DVD" as soon as possible. The recorder Title lister tends to give a "false" sense of security.. look under the covers and its pretty scary on the hard disk.

note: This should have been "intuitive" since these recorders only had a single hard drive, nothing RAID or Redundant, the slightest twitch or glitch could permanently and mysteriously delete a recording.. leaving you wondering if you did that, one of your kids.. or the dog. Or worse.. a Title list that is duplicated, branching or that hangs the recorder while trying to boot. (I had unrealistic assumptions of "quality" in these recorders until I witnessed the reality of the situation first hand.)

Basically you want to use the recorder to make recordings, then regularly delete every single recording to "Purge" the Title list and the available block list on the hard drive. So that it can untangle the string or twine that multiple fragmented recordings can become. Trying to use them for long term "Jukebox" or "Media Server" duty is ridiculous.

We're backing off adding more brands and models for now.. but I've pushed ahead slightly and (looked) at the JVC DVM700.

I am not a coder.. but IsoBuster makes probing fairly easy..

I can see the outlines of a JVC PARTITION TABLE, JVC ORIG FS Ver2 a bunch of DIR with ifo and vobs.. and its not encrypted.

Its also not based on the Polaroid / LSI - TFS2 filesystem.. which is a relief..

If or when it will be supported is kind of a guess at this point.

There are hints that the previous JVC DVM600 and perhaps the JVC DVM70 used the same filesystem. So adding support for one, may add support for them all in short order.

Peter did solve his curiosity regarding the Medion recorder, which strongly resembled some LG and Euro brands. It turned out to be a LiteOn in disguise. LiteOns tend to share a lot in common with dosFAT filesystems but some of the organization an hinting is a bit off.. but he might be able to get that in as well.

That's the news for now.

Last edited by jwillis84; 05-22-2019 at 10:30 PM.
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07-02-2019, 05:11 AM
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Any new news on the LSI recorders front?
Either Polaroid or JVC are my main focus and interest.

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07-02-2019, 09:51 AM
jwillis84 jwillis84 is offline
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Nothing coming very soon.

Less progress on the Polaroid than on the JVC.

Polaroid is based on the TFS2 format invented by LSI which is very poorly understood. I mean there are lots of known data points and overall organization. But nothing that clearly links the bitmaps to the 16 MB storage chunks in the file system. It seems it was mostly used in eastern Europe and for some consulting work in the US but its was sporadic and never very popular. I don't think anyone familar with it is still around... either left technology behind or well.. no longer on the internet.

JVC MX (no progress), JVC DVM some progress from me, but Peter (despite the name his alter ego isn't Spiderman).. had to focus on locking down support for the new file sytems discovered in the DVRs that are officially supported and produce a real official release.

The DMV file system is not as crazy as the TFS2. The names being assigned to these file systems are in plain text in the header of the volumes discovered on the hard disk. JVC apparently like Panasonic "invented their own" but it still has similarities to DVD-VR. JVC like Panasonic was a late comer to the Mt Fuji summits that Toshiba established with Pioneer and others.. that's sort of why I think JVC is on par with Panasonic for difficulty. But Panasonic made many more models and they're easier to find in garage sales and far cheaper.

With JVC its therefore harder to see "patterns" in the storage since there are far fewer samples. We've tried making recordings and varying things like time and date to figure out how recordings are assigned their time and date in the meta on the hard disk.. its not bit encoded or even encrypted.. but position and decimal digit stored.. so its like like looking at plain English.. but takes a lot of time.

MPEG2 data is huge, its like "Big Foot" huge.. it would be very hard to encrypt all that with the slow processors of those days.. so they didn't.. its just smeared all over the tracks of the hard drive.. mostly one GOP after another.. think peanut butter on toast.. its pretty hard to miss. Those hard drives are "Giganitcally" slow and lethargic.. they "had to be" to keep the noise and heat down inside those cases.. and still they were noisy and ran hot. So in a way that makes the task far easier than most people ever imagined.. its very tedious.. but not impossible.

But you have to (a) find the meta data per recording.. done (b) find recording names and data and time stamps.. done (c) figure out where a recording begins from the meta data.. [not done] (d) figure out how to accomodate fragmentation and "breakage" when they add features like timeshifting, or divide up a title.. then do it terribly, damaging the original recording.. which happens.. far too much.


I have not given up.. but I am getting more branching interests and demands on my time.

1. SONY DHG - i "think" I've found a way to emulate old fashion tvgos time and date settings with a pi-zero, which has an old fashioned Composite output.. which can feed an RF modulator and set dvr clocks.. but.. what to do with the gemstar stuff.. mostly want to avoid conflicts with that.

2. many capture devices over USB are capable of uncompressed or compressed transport of audio and video to a pc.. but its far too common the audio pin is also on the video device driver and can't be seen by most software.. the fundamental (default paradigm) back then was (don't do that).. only Virtual Dub diverged and specifically.. "did that.. default audio to video capture device". Instead they were suppose to install two device drivers for the same device, one for the video capture and one for the audio capture and make it look like two separate devices.. this was why applications like "lync" or "chat" always asked you to select a video device (then) an audio device from separate "lists".. its simply "the way things were done" right up to this day. -- There are "virtual audio" kernel drivers which can "snatch" the output from a pin on one device and make it appear as an entirely different virtual device.. which might solve this problem for a lot of old capture devices.. but right now people are calling me nuts for pursuing the idea... I get called "nuts" a lot.

3. finding more old DVRs and testing with the existing IsoBuster 2019 edition also consumes time.. and is instantly gratifying. And I get low level grumble mail (why weren't you around ten years ago..?) that sort of thing.. and its kind of depressing.. which slows me down on all fronts.. i have to take breaks.

Summary.. so yeah, JVC support is probably coming as soon as I or Peter, or we have a break through.. its not that far fetched a possiblity. A Polaroid break through is less likely. Either the interest is not there.. or the people who could have given us a clue to understanding TFS2 have simply passed away.

.. a plug for "existing" supported brands and models since March 2019, .. Toshiba, RCA/Thompson, Philips, Magnavox, Pioneer (all models), Panasonic.. total almost 60 specific models which have been physically tested and are known to be working.

Last edited by jwillis84; 07-02-2019 at 10:46 AM.
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