Film-Tech Forum ARCHIVE: SDDS digital format delay

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Posted by Antonio Marcheselli (Member # 373) on 03-07-2004, 06:12 PM:

Hi everyone

I'm working with two SDDS 3000 that have a strange behaviour. When a digital format (DD or DTS) is ready to take place of the SR the 3000 switch to DD/DTS (from SR) only AFTER 6 seconds. Results: every trailer and sound logo starts in SR and switch in DD or DTS after 6 seconds. Thinks of the DTS "flying disk" that switch in DTS during the louder scenes... Terrible! Or a DD dropout during a reel change that switch back to DD only after 6 seconds...

Is there a way to correct this setup? I'm not so familiar with the SDDS setup software.

Thanks for your help

Bye

Antonio

Posted by Brad Miller (Member # 2) on 03-07-2004, 08:03 PM:

What version of the software are you using?

Posted by Alan Haigh (Member # 1781) on 03-08-2004, 01:39 AM:

If you have the latest software, then a preset change at the the start of the trailer should stop it happening.

Alan

Posted by Antonio Marcheselli (Member # 373) on 03-08-2004, 05:15 PM:

Brad,

I'm so unfamiliar with the DFP that... I do not know how to check software version... [uhoh]

I dind't had time to learn much on that processor. How can I check it?

Thanks!

Bye
A

Posted by Robbie Hidalgo (Member # 2090) on 03-09-2004, 03:11 AM:

Antonio,

How to check DFP-D3000 Firmware:
1) From the front panel, press the Down arrow while any Preset is selected.
2) Press the Right arrow until the word MENU is flashing.
3) Press SELECT.
4) The first option which appears (already flashing) is STATUS. This is the one you want, so....
5) Press SELECT
6) Now Power and Film Run hours are displayed. Look in the upper right corner of the LCD display, and you will see the firmware version "v2.xx". The latest version is v2.92.

This can also be checked from the Setup Software, under the STATUS menu. Front panel is faster.

And Alan is right. A preset change will stop this. If the D3000 sees a burst of reversions occuring when it is operating in it's multiple-fallback mode, it may hold SR until it sees the errors subside. If you cue a preset switch, it will not apply this algorithm. Check splices, they can sometimes cause sudden error bursts if the splice is questionable, or if there is any significant handling damage around the splice points.

Posted by Antonio Marcheselli (Member # 373) on 03-09-2004, 04:52 PM:

The software version is 2.92 for both of my player.

Robbie and Alan
Do you mean that DFP works as Dolby's CP unit and when multiple SR drop occours it will stay in SR until it says a stable digital input?

I do not think that it is not my case. Let me give you an example.

Trailer 1. The trailer goes fine in SRD (say 4 error rate) up to the end. At the end the DA20 drops to Analog just at the splice. The DA20 switch immediately to SRD, without multiple dropouts. Error rate is again 4.

Well, the DFP3000 stays in SR (with DA20 in DIGITAL mode) up to 6 seconds.

The same for DTS. Let's say you play a THX trailer. DTS 6D starts to play in DIGITAL at the right point, with stable timecode.
But the DFP3000 switch to DTS only after 6 seconds. If DTS drops to analog just once, the DFP won't switch to DTS again before 6 seconds.

Is there something wrong?

Bye and thanks!

Antonio

Posted by Robb Johnston (Member # 239) on 03-09-2004, 10:17 PM:

I think I know what you are describing, but I forget how to fix it. I remember that there is a delay that you can set that is a fade between formats. For example when the show starts, I think the default was that non-sync sould shut off for 6 seconds before the SR would come on. Or maybe it stayed in non-sync until 6 seconds after the first snipe was on screen.

I don't remember how it was done, but it was a very simple thing to do, we changed the setting on all 14 processors in a matter of minutes.

I would think that if there was a 6 second delay on one format change, perhaps it can exist on all of them. Does this sound familiar to anyone else?

Posted by Michael Schaffer (Member # 1204) on 03-10-2004, 12:13 AM:

Yes, but this delay only applies to changes from/to nonsync. It can be configured with the setup software, or by pressing the down arrow button when in the nonsync preset, then there is theat setting in seconds and you can change it with the fader knob. But that is not Antonio's problem.
As was discussed recently and Mr Hidalgo reminded me, there are some problems that can be caused when the changeover delay settings are screwed up. Best to make sure they are set to 7 seconds on both projectors.

Posted by Antonio Marcheselli (Member # 373) on 03-10-2004, 05:37 AM:

Hi Michael

Thanks for your reply!

It is not a changeover system (at least one of them... One is a single V5, the other is V5+V8 used only for 70mm shows).

Are you saying that if the changeover time is different from 7 seconds this behaviour can happen?

I do not know how much seconds are set in the processors, I'll check soon.

However, I understand that this delay is not "normal" for a sony DFP, am I right?

Bye

Antonio

Posted by Alan Haigh (Member # 1781) on 03-10-2004, 09:43 AM:

This "feature" was implemented to stop the sound rapidly switching between digital and analogue, which can be annoying. It works like this.

1. Switch to any digital preset (SDDS, SRD, DTS). processor is in analogue now until it sees a digital signal.
2. digital data is recieved. 3000 goes immediately to digital with no delay.
3. There is a drop out. 3000 stays in analogue for 2 seconds - if no other drop outs occur, it goes back to digital.
4. If another drop out occurs within 2 seconds, the time in analogue is doubled to 4 seconds
5. and so on up to a maximum of (I think) 126 seconds.

This seems great, as long as the feature is playing. The problem occurs with trailers of different formats. So if you have 2 analogue trailers (or ads) and then digital, it will pick up straight away. however if you have digital-analogue-digital then the 3000 treats the analogue trailer as errors and holds the processor in analogue for 2 seconds to make sure the data is going to stay in digital reliably.

As I said, the cure for this is to program a preset change at the start of the second digital trailer (i.e. the start of the 3rd trailer in the example above). This will reset this function of the processor and the processor will be in digital the instant it switches. Remember the minimum drop out time is 2 seconds.

Alan

Posted by Michael Schaffer (Member # 1204) on 03-10-2004, 11:09 AM:

Antonio - it does not matter if the system is changeover or not. It can produce funny results, so check the settings just to make sure.
Based on what Alan said, do you have a lot of change from analog to digital trailers, or have all trailers Dolby Digital tracks? It probably doesn't matter since dropouts occur anyway. So try the solution Alan has suggested.
An alternative solution might be to simply play the trailers before the sound format logo in analog. I don't know if you also have the problem with uniform excessive trailer loudness in Italy, but if so, this will help keep them down a little.

Posted by Antonio Marcheselli (Member # 373) on 03-10-2004, 05:45 PM:

Thanks Alan and Michael

I have no problem of loudness, our automation keeps the trailers and ADV at -11dB.

Does not seem a good feature, IMHO, since all digital trailers, sound logo and (eventually if a splice is not so good or if the print is not so good) reel change has a 2/4/8 seconds of dropouts...

I will check better tomorrow now that I know how does it works.

So every DFP3000 installed worldwide is unable to show a THX trailer or a DTS trailer in its best shape? [Smile]

I found the Dolby's algorithm better than sony's. If the dropouts are multiple, THEN the processor stays in analog for a while.

Alan,
Is is possible that the Sony decide to stay in analog after many many digital dropouts? I have a damaged DD trailer in front of a movie (don't ask...) and I found the DFP in backup SR two times in the middle of the feature, where the DA20 sees a stable 4 as error rate. Is is possible that the DFP decided to switch definitively in SR? The solution was turn off and on the digital LED... Swithing to SR (preset 03) and then back to SRD (preset 04) didn't fix the problem.

Thanks for your help!

Bye
Antonio

Posted by Robbie Hidalgo (Member # 2090) on 03-10-2004, 11:20 PM:

quote:
So every DFP3000 installed worldwide is unable to show a THX trailer or a DTS trailer in its best shape?

Antonio,

The algorithm generated many interesting debates during DFP3000 development. But the DFP is flexible enough to function without any analog delays by using your automation to switch trailer formats. And actually, if you connect DD or DTS to the DFP using traditional methods (preset switching) rather than the DFP's internal multi-fallback mode, the algorithm will be completely bypassed either during trailers or feature. The positive side being, you can choose to have it function with or without the algorithm as defined by your system's integration.

It was indeed intended that the DFP could still operate either way for those who have situational problems with one method or another. I, like Alan and you, also have mixed feelings about some of the parameters of the algorithm...you are not alone. But, the DFP can nevertheless be made to work as you wish it to.

Regarding your experience with the DD not recovering until you switch the DD Reader LED off/on, it is important to isolate the incoming logic from DD from the algorithm inside the DFP. In DFP v2.92, manually re-selecting a preset (as you tried) always resets the internal algorithm by design, and DD should have immediately started playing. However, DFP needs to see the proper incoming logic from DD or DTS before playing it. Based on your info, this should be a low-level logic state from DA-20 to DFP's Pin 34(AUX1) or 35(AUX2). If that logic state is correct, then when you reselect DD's preset (out to SR, back to DD for example), DFP will play DD immediately with no delay. If DD is not sending the proper logic state to the DFP, then the DFP will revert back to SR until DD pulls the logic low, no matter what is showing on the DA-20 error display.

Double check that your DA-20 is configured for CP-200 mode (latching logic) rather than it's default CP-65 mode. (Switch position 3 on Cat. 611 = CP-200 mode). If it is already on Switch position 3, something may be fishy in the DA-20 or the interface. If it is not in switch position 3, be careful before setting it there. It is mandatory that the interface wiring be exactly as illustrated in the Tech Note before setting the DA-20 to CP-200 mode. (The doc is of course available here at F-T).

Posted by Alan Haigh (Member # 1781) on 03-12-2004, 04:20 PM:

Hello Antonio

The 3000 definitely won't just stay in analogue if it has had bad data in the past. After 2 minutes of good data it will go back to digital. I think the DA20 does give up "forever" though, but it should have the orange analogue light on if that's the case.

As Robbie says there are 2 ways of setting up the switching. There is preset switching, just like DTS and DA20s with a CP65 - here the processors will actually switch presets. However this can be confusing. The 3000 can have multiple fallbacks. If there is no SDDS it plays DTS, if not then SRD, if not then SR (you can set this up in any order) You can imagine the chaos if all these processors were switching presets at the same time, as well as the automation system! The "level logic" (which come to think of it I think Robbie himself thought of originally!) uses a constant "high" or "low" voltage at 2 pins, one for aux 1 and one for aux 2. Low means digital. In the DA20/DTS this line was originally designed to switch the gain of the subwoofer in the CP200, hence CP200 mode.

Just a bit of additional info

Alan

Posted by Antonio Marcheselli (Member # 373) on 03-12-2004, 06:36 PM:

Alan and Robbie

Thanks for your replies.
I really know nothing on these processors, I still have to read the manuals!

Correct me if I'm wrong: If the DFP is connected in a traditional "pulse" mode the unit works as a DTS6D connected to a CP500. When the DTS is ready it switch the CP in Format 11 and back to Format 05 when not ready anymore.

This may cause some problems with a DTS and DA20 pulsing and switching in and out.
In this way the format change is with NO delay.

Otherwise the DFP can be configured to see what format is active and choose from them basing on the list configured during installation. So, DTS for main format, SRD as first fallback and SR as third.

In this way the DFP uses its internal logic switching between formats with its delay. However the logic is bypassed when I manually call a format.

I think that our DFP are configured as the second way since when the DTS kiks has "SRD" as backup format and not SR.

I tried to switch on and off the dolby digital LED during a trailer to better understand the behaviour of the processor but I really miss the point...
The processor has always 2/3 seconds of delay between SR to DD (counting after the DIGITAL led is turned on on DA20) regardless the dropouts. If I turn off the LED, then ON and then OFF few times (so that the DFP sees multiple dropouts during its delay time) the processor go back to SRD always after 2/3 seconds. No bigger delays.

And If I Re-Select the same preset during the SR-delay I noted no immediate selecting of the digital format.

Our automation calls for Preset 4 at the start of the trailers... I cannot have the automation call for Preset 4 at the beginning of each trailers!

The strange situation I found the processor last time (SR backup) has disappeared, perhaps was just one time.

Let me know if what I said is right or not!

Thenks for your time

Antonio

Posted by Michael Schaffer (Member # 1204) on 03-12-2004, 07:45 PM:

Antonio, please read the technote and the quick start guide.

Posted by Antonio Marcheselli (Member # 373) on 03-13-2004, 03:22 PM:

Yes Michael,

You told me! [Roll Eyes]

Sorry, I will found time to learn more of that processors!

Bye
A

Posted by Alan Haigh (Member # 1781) on 03-14-2004, 04:24 AM:

Antonio, you are almost there.

In the second mode you describe. The non-preset switching, constant level fallback mode. Selecting a preset doesn't make the processor ignore these levels. It is constantly monitoring to see which pins are low or high, so it plays the correct format instantly. However the "feature" we talked about where it holds in analogue for 2 seconds is reset. This only happens when you select a DIFFERENT preset, not the same one.

Switching the SRD light on and off - well I'm not sure this will make it hold analogue for longer. If there is a small drop out which goes to analogue then straight back to digital, the processor will be in analogue for 2 seconds, UNLESS there is another digital to analogue drop out within that 2 seconds. Turning the light off and on probably takes the processor more than 2 seconds, so you will probably see it go to digital 2 seconds after the DA20 picks up. To test this you need to rapidly switch between analogue and digital somehow.

Trailers - Does the DA20 always revert briefly to analogue between trailers? SDDS and DTS will stay in digital over the join, which is probably what the processor designers were assuming...

Posted by Antonio Marcheselli (Member # 373) on 03-14-2004, 07:53 AM:

Alan

I tried swithing off the digital LED rapidly while the DFP was in the 2 seconds analog fallback. IN this way, when the LED is defintively turned on I should see the DFP come back to digital more than 2 seconds... isn't it? I saw the same 2 seconds instead.

Yes, the DA20 drops briefly between trailers and this causes the DFP to stay in SR for a while before reverting in digital again.

DTS is not affected, ok, but what abou when the DTS or THX trailers begins? Two seconds is too much, the sound is already in the louder scenes!

I've downloaded all the manuals, I will learn more soon.

Thanks for your time

Bye
A

Posted by Antonio Marcheselli (Member # 373) on 03-17-2004, 04:45 PM:

Michael

I read the quick start manual and the technotes.
I realized that the DFP is cabled so that it can see what format is working so that it can decide the fallback formats.

I also realize what Alan said about changing the preset manually: If I switch in SR and then in SRD during an SRD print the processor does not wait two seconds before switch in SRD.

However If I correctly realized the situation there is no solution to my issue. The DFP will always wait two seconds before change to an AUX if there was a dropuout. I didn't understand what Alan suggest about have the automation call for the preset... If I set Preset 4 (SRD) from Preset 3 (SR) the DFP switch immediately in SRD. But the next trailer I have the same problem and I should switch in SR and back in SRD in a very syncronous mode!!

Tell me if this time I understood correctly!
Bye
A