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Author Topic: "Pedro Box"
Osi Osgood
Film God

Posts: 10167
From: #399R K.O.A. Mountian Home, ID. 83647
Registered: Jul 2005


 - posted November 11, 2017 11:24 AM      Profile for Osi Osgood   Author's Homepage   Email Osi Osgood   Send New Private Message       Edit/Delete Post 
I;ve heard this thing talked about for years, but i still don't know ...

1. Who manufactured it.
2. What does it exactly do?
3. How to use it.

Though artistic, i am not the best person when it comes to high precision stuff, but I'd like to know if I'd want to sync a recording for super 8 off of a DVD or laserdisc.

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"All these moments will be lost in time, just like ... tears, in the rain. "

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1630
From: California
Registered: Aug 2007


 - posted November 17, 2017 12:13 AM      Profile for Bill Brandenstein   Email Bill Brandenstein   Send New Private Message       Edit/Delete Post 
A worthy quest, but sadly is now a tough one.

1. "Pedro" is the pseudonym of Wolfgang Thuille, who used to have a website and built these sync boxes and shipped them everywhere.

2. These made second-sound-system technologies on Elmo GS-1200s and apparently some Bauer projectors work. The European ones would read a 25Hz PAL video signal and output an ESS control pulse that would synchronize a GS-1200 to (probably and hopefully) a DVD in 5.1. The US ones lacked the ability to read a video signal because of the weird 23.976 rate our NTSC video forces us into. Instead, he had a quartz crystal speed generator that would make its own 23.976 pulse without listening to any external input. So a close guess, but technically "wild" sync. These boxes weren't cheap! He also made a simpler one that I bought that takes an audio input and converts them to the square pulse that the GS-1200 syncs to. That allows for a control track to be played from a computer or other device, making use of inexpensive existing gear.

3. Depends on the model of the Pedro Box. Operation varies greatly according to which one.

Hopefully that helps!

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted November 18, 2017 04:07 AM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
Hi, there. The most basic one (which I own) is capable to output a control signal to the ESS input socket of the Gs 1200 in order to have it run at precisely 16 & 2/3, 18, 24 and 25 fps (quartz lock): this means it can be used to sync to an American DVD runnung at 24 fps (or a Bluray for that matter),no problems whatsoever. And it does not need a video input to generate the reference signal: it generates it on its own

--------------------
Maurizio

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1630
From: California
Registered: Aug 2007


 - posted November 18, 2017 11:18 AM      Profile for Bill Brandenstein   Email Bill Brandenstein   Send New Private Message       Edit/Delete Post 
Maurizio, there is an even more basic one than what you're describing, and that's the one I have. There is NO internal quartz control; I have to feed it an external audio source with beeps at the correct frame intervals. With what I do in software, it suits me perfectly.

So I believe there are 3 levels to this product:
1) no internal oscillator or control, a simple conversion box
2) internal quartz time generation for reasonably accurate "wild" sync
3) all of the above, plus the ability to "read" a video source (PAL only, I believe)

Now that Pedro has disappeared from the scene, it would be nice if someone would begin to produce #1 again, as any computer with 2 or more audio outs could drive this. And at this point that's pretty much any run-of-the-mill desktop computer.

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Claus Harding
Phenomenal Film Handler

Posts: 1131
From: Washington DC
Registered: Oct 2006


 - posted November 18, 2017 01:26 PM      Profile for Claus Harding   Email Claus Harding   Send New Private Message       Edit/Delete Post 
Having seen the box in action, it truly is the closest to "magic" one can imagine: that a silent Super-8 200-footer can get lip-sync sound from a DVD in real-time, with decades separating the technology, is, to me at least, astounding. It would be great if someone took up the mantle and made the boxes again.

C.

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"Why are there shots of deserts in a scene that's supposed to take place in Belgium during the winter?" (Review of 'Battle of the Bulge'.)

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Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016


 - posted November 18, 2017 04:22 PM      Profile for Renzo Dal Bo   Email Renzo Dal Bo   Send New Private Message       Edit/Delete Post 
Hi everyone,
I never had any type of Pedro's box, but reading a lot about that and its marvelous features and taking inspiration from a previous project of mine (where you can read about it here), I built a prototype of a sync box with all the characteristics of the old Pedro's box.
Despite it is a home made device, it works very well and it is able to generate sync pulses of fixed frequencies (16,667 - 18 - 23.976 - 24 - 25 fps) to drive the GS1200 with high accuracy through the ESS socket.
My box is based on an Arduino board and it is programmed to start and stop the sync pulses of a frequency, choosen from the above list, pressing a button.
It is also possible to provide the box of a secondary circuitry to generate the pulses at 25 fps, from a video (PAL) analog source.

Renzo

[ November 24, 2017, 11:52 AM: Message edited by: Renzo Dal Bo ]

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted November 18, 2017 04:29 PM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
Hi Renzo. Having seen some of your achievements, I can only vouch for what you do. Could you make some of these devices for others?

--------------------
Maurizio

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Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016


 - posted November 20, 2017 05:15 AM      Profile for Renzo Dal Bo   Email Renzo Dal Bo   Send New Private Message       Edit/Delete Post 
Hi Maurizio, nice to meet you here.
Yes, of course, I could! But I don't think there is such an interest for a new sync box, as it can be easily substituted by a computer with a proper software.
My box, although full working, is still a raw project .
It would need a tester who own the original box to compare its good functioning. You could be that person!
If there is someone interested in this sync box, before to build other new boxes, I could send you the prototype for testing, if you agree.

Renzo

[ January 03, 2018, 04:32 PM: Message edited by: Renzo Dal Bo ]

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Paul Browning
Phenomenal Film Handler

Posts: 1002
From: West Midlands United Kingdom
Registered: Aug 2011


 - posted November 20, 2017 06:22 AM      Profile for Paul Browning   Email Paul Browning   Send New Private Message       Edit/Delete Post 
Hi Renzo, I have the all singing all dancing pedro box, and the other box of Pedro's to make a comparison, perhaps it might be worth finding out if there is enough interest in the box before you spend time making them, but I could also test it for you in a like for like situation if needed......

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted November 20, 2017 03:39 PM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
No problems with me Renzo. If/when you want to proceed, just drop me a line via the message service of this forum and I'll send you my home address. Cheers

--------------------
Maurizio

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Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016


 - posted November 24, 2017 11:45 AM      Profile for Renzo Dal Bo   Email Renzo Dal Bo   Send New Private Message       Edit/Delete Post 
Thank you, Paul and Maurizio, for your willingness to test my sync box for Elmo GS1200.
At the moment, my prototype is equivalent to the P1008GS-Q original sync box, but, in addition to the four original frequencies, it allows to sync the projector also to the NTSC frequency of 23,976 Hz.
As soon as I put the prototype in an appropriate "box", I will contact you to organize the comparison test.

Renzo

 -

[ November 24, 2017, 05:13 PM: Message edited by: Renzo Dal Bo ]

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted November 28, 2017 03:52 PM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
Hello, Renzo. I see you chose to use a battery as power source, instead of the power output supplied by the ESS socket. Considering aging of some components, which might lead to whimisical performance by the original box, this is a good provision.

Are you also planning (or have you planned) to include an external power supply input?

I confess I am very curious.

Later,

Maurizio

--------------------
Maurizio

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Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016


 - posted January 04, 2018 06:03 PM      Profile for Renzo Dal Bo   Email Renzo Dal Bo   Send New Private Message       Edit/Delete Post 
Finally Boxed !!!

It took a bit of time to accommodate all the electronics in a box with small dimensions. For sure more time than to build the prototype. I wanted it was well fitted and rationally arranged.

Maurizio,
at the moment the sync box is powered by a 9V battery, but it is no problem to provide it with a socket for an external 9V DC power supply.

I am sorry for the craft label, I hope it makes to understand how the sync box works. After turning on the "Power" switch, the "Speed Selection" button allows you to select the desired speed, reported by a led. The "ESS Pulse" switch allows to start and stop the ESS pulse signals to send to the GS1200, connected by the DIN plug.

The accuracy of the pulses is very high. For all the speeds, the error is lower than one frame/hour.

Ready for third parties tests!

Renzo

 -

[ January 07, 2018, 06:54 PM: Message edited by: Renzo Dal Bo ]

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Joe Taffis
Phenomenal Film Handler

Posts: 1580
From: United States
Registered: Jun 2003


 - posted January 05, 2018 09:37 AM      Profile for Joe Taffis   Email Joe Taffis   Send New Private Message       Edit/Delete Post 
Renzo, That's very good news! I'm sure many of us are looking forward to seeing the test results [Smile]

--------------------
Joe Taffis

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Osi Osgood
Film God

Posts: 10167
From: #399R K.O.A. Mountian Home, ID. 83647
Registered: Jul 2005


 - posted January 05, 2018 10:44 AM      Profile for Osi Osgood   Author's Homepage   Email Osi Osgood   Send New Private Message       Edit/Delete Post 
What an awesome invention! I'll be curious to hear the results as well! [Smile]

--------------------
"All these moments will be lost in time, just like ... tears, in the rain. "

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted January 05, 2018 12:55 PM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
Hello, Renzo.

I've just received some films to transfer to my NLE for redubbing in Italian and I will have a lot of work for this unit. The film that I will be transferring will provide a visual and time reference to edit and conform the DVD's audio. Needless to say all of this requires the utmost accuracy but I am sure your sync box will handle the task flawlessly. Are you still willing to let me test it?

--------------------
Maurizio

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1630
From: California
Registered: Aug 2007


 - posted January 05, 2018 05:22 PM      Profile for Bill Brandenstein   Email Bill Brandenstein   Send New Private Message       Edit/Delete Post 
Renzo, congratulations on a great product, and I hope you can sell a good many of them in due time!

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Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016


 - posted January 07, 2018 09:49 AM      Profile for Renzo Dal Bo   Email Renzo Dal Bo   Send New Private Message       Edit/Delete Post 
Thank you all for your positive and gratifying comments, but I am walking on eggshelds and here I wish to explain why.
I am only a passionate, just like you, that loves to experiment, above all to understand how the things work. I am not a professional, but only one who likes put his nose in different activitives. So my main target is to satisfy my curiosity and I never thought to gain money about that. When Maurizio asked me if I am willing to build the box for others, I answered positively, because it is always a pleasure to help other passionates when they are in need. To answer those who contacted me private to know if I sell this sync box, I say: "maybe, only if and when I will be sure it properly works".

I have to admit it is very hard to master all the variables of this task, maybe it is impossible. I try to explain myself despite my poor english.
In my project I can calibrate accurately the synch box in way it generates pulses taking, as reference, the crystal built in the Arduino board, so the projector is led by that. When you play separately the soundtrack, with your computer or a DVD player, and you want it to stay in sync with your projector, they take, as time reference, their own built in crystals. All the crystals produce relative time references and not absolute references. However precise, they could be a little different and drift for some reasons (one of these is the temperature). These very very small differences, sometime random, can produce in long times not acceptable differences. For example, an imperceptible lack of one thousandth of second at 24 fps, after an hour, produces an error of 86 frames.
To solve the problem, one simple and safe way is to adopt the same time reference source.
When you play concurrently by a computer the soundtrack and the track with the pulses, they will stay always in sync, because they refer to the same time reference produced by the computer itself.
So you already understand that to aspect a perfect sync for long times in a "wild" sync is almost impossible to achieve.
And, though I have never owned one, I believe also the Pedro's box is not able to keep the projector in sync for long time.
However, what I made to maintain a separate box, just like Pedro's one, and, in spite of everything, to improve its accuracy, is to "tune" my box to my computer or my DVD player. I don't want to bore you telling how, it would be complicated for me here.
Briefly, first I estimate the error and then I modify the program in the Arduino board to compensate it.
Therefore my box is very precise with my equipment, because it's tailored on it, and I always have the possibility to change its program and to adapt it to a new equipment. Usually they are tiny adjustments (some micro seconds).
So, at the moment, I cannot guarantee the same precision with other stuff. For now I would say my box is quite precise, I hope as precise as Pedro's box. This is the reason I asked someone, who have the Pedro's one, to test mine.

Maurizio, you are the man!
I already have your address, but I would like to contact you by phone, please could you send me your phone number private?

Thank you all again

Renzo

[ March 02, 2018, 04:26 AM: Message edited by: Renzo Dal Bo ]

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 976
From: Ortona, Italy
Registered: Jan 2004


 - posted January 08, 2018 03:32 PM      Profile for Maurizio Di Cintio   Email Maurizio Di Cintio   Send New Private Message       Edit/Delete Post 
Hello, Renzo.

PM sent.

--------------------
Maurizio

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1630
From: California
Registered: Aug 2007


 - posted January 09, 2018 11:18 AM      Profile for Bill Brandenstein   Email Bill Brandenstein   Send New Private Message       Edit/Delete Post 
Renzo, for doing this as an amateur, your results certainly look professional! I'm not sure Pedro's efforts are any better, with possibly one exception: accepting an external input. You're correct that "wild" sync is only trustworthy to a point. Some of Pedro's boxes accepted an external input of a PAL (standard definition) TV signal and the box would output the pulse for 25.00fps to match. Unfortunately, he never offered an NTSC version, so I'm presuming he achieved this with rudimentary electronics.

My Pedro box has no crystal oscillator nor video input. There are two audio inputs only. So it's driven by a standard line-level audio input (RCA) or connector from a Bauer camera-type system. If I create a series of short beeps and play it into this Pedro box, the projector can be adjusted to match the frame rate perfectly, and then there is no drift.

Some people have had success creating an ESS pulse directly from their computer sound card, but mine didn't work.

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Paul Browning
Phenomenal Film Handler

Posts: 1002
From: West Midlands United Kingdom
Registered: Aug 2011


 - posted January 09, 2018 12:04 PM      Profile for Paul Browning   Email Paul Browning   Send New Private Message       Edit/Delete Post 
Bill I have the more sophisticated box by pedro, and any fps can be dialled in and locked crystal sync, he has preset the common fps already including the NTSC, with this box its an added feature for you guys across the pond, and on in some cases dvds in the uk that are imports, all that said a very good addition.

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1630
From: California
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 - posted January 09, 2018 04:37 PM      Profile for Bill Brandenstein   Email Bill Brandenstein   Send New Private Message       Edit/Delete Post 
Agreed, Paul, but that is still technically "wild" sync. Which can work very, very well. But nothing beats having a pulse control track that starts, stops, and stays locked frame-accurate with the audio for the full duration. To make "wild" sync work, not only do your audio source and Pedro box need to drift very little from one another, but you also have to be a bit lucky and hit "start" manually at just the right instant - or adjust the projector later by eye.

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Paul Browning
Phenomenal Film Handler

Posts: 1002
From: West Midlands United Kingdom
Registered: Aug 2011


 - posted January 10, 2018 01:21 AM      Profile for Paul Browning   Email Paul Browning   Send New Private Message       Edit/Delete Post 
There is a disc Bill sent with the kit with the beeps on to automatically start the projector, there is also a manual giving the full details of different setups, most of them I would think, but its a little difficult to understand in parts but nothing is missed, Pedro was obviously doing this for a living or an incredibly keen amateur......

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Renzo Dal Bo
Film Handler

Posts: 70
From: Mogliano Veneto, Italy
Registered: Dec 2016


 - posted January 11, 2018 06:06 AM      Profile for Renzo Dal Bo   Email Renzo Dal Bo   Send New Private Message       Edit/Delete Post 
Hi
I have already contacted Maurizio to arrange a deep test.
I will ship my sync box to him, who will judge if it works like Pedro's one, dubbing a feature film. I know he is a master in this kind of job.
Nevertheless in order to improve my project, I am looking for any information regarding the old boxes. In particular I wish to ask you some good photos of the sync boxes you own, or any kind of instruction manual about that. I need to understand how they works, because I will try to reproduce their feautures in my project. Thank you all.

Renzo

[ January 11, 2018, 11:52 AM: Message edited by: Renzo Dal Bo ]

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Bill Brandenstein
Phenomenal Film Handler

Posts: 1630
From: California
Registered: Aug 2007


 - posted January 18, 2018 12:08 PM      Profile for Bill Brandenstein   Email Bill Brandenstein   Send New Private Message       Edit/Delete Post 
So here's what I have. This has to be the simplest of Pedro boxes:

 -

It has an input on the left side for 9V DC power and I had to supply my own "wall wart." Otherwise, it's very simple: you have audio waveform inputs either into the Bauer DIN jack, or the RCA jack. As you see, Pedro labelled it for -10dB audio with 1000Hz cue beeps, so this box has no timing ability of its own. All it does is convert an audio trigger into the square pulse read by the GS-1200.

He sent a CD with my box with 1Khz pulse tracks at various frame rates, although I know now that some of the timing wasn't perfectly correct. Any consumer line-level audio device can thus play into this device, and if the level isn't hot enough, the green LED doesn't illuminate. Under normal operation, the LED pulses once for each trigger pulse it "hears."

So I ended up making my own control tracks with 1KHz "beeps" about 10ms long, then an appropriate length of silence. At 48KHz (which is what all DVDs use) a framerate of 23.976 corresponds neatly to a beep for every 2002 audio samples. Lots of other options work also, and I have quite a few different files for different frame rates. They can be shared!!!

So you can make a control CD of a mono track with the pulse on one channel and the audio content on the other. I've "added" sound to silent prints this way. But most often I use a computer. Almost any Windows office computer now has audio on the motherboard with multiple outputs, and as long as you can set the driver to use them independently, you're good to go. Any audio software that handles more than one track and file at a time can be used. So you send a pulse file to one output hooked up to this Pedro box, and the other output to whatever you hear your sound through. It takes two pulses to bring the projector up to speed, so all of my ESS sessions have two pulses before the "Start" frame cue. As mentioned before, a Dolby Digital SPDIF-wave file will play perfectly over a digital connection in this manner while a pulse track plays out of an analog headphone jack, but it requires Windows XP and Adobe Audition 3.0 to keep the SPDIF data intact and undithered. Of all the Adobe / Cool Edit products, that's the only version that can pass an unaltered bitstream. I've not tried this with any other software.

It's also important to note that whatever speed the trigger cue file is made for is matched by the projector settings. The Elmo GS-1200 has speed and level controls for the pulse, and a little meter for the latter. If you have a pulse playing at 24 fps and the projector is set to 18, or rates match but the speed control is bumped much either way, the meter will dance around most unhappily. You can run and lock any speed within the projector's range so long as you match the projector's controls to your ESS "playback" so the Elmo "knows" what to expect. The meter sits still and stable when it's done right.

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