Film-Tech Forum ARCHIVE: Dolby DSS100 ajust time

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Posted by Michel Pomerleau (Member # 7117) on 03-02-2015, 05:47 PM:

Hi, the DSS100 dosen't have the exact time, it has 5 min off
the real time, and the show start always 5 min late, there is a way
to ajust the time, it is connected to a Doremi TMS, the TMS have the right time.

Posted by Leo Enticknap (Member # 534) on 03-02-2015, 05:59 PM:

With a 200, you can change the time in the BIOS settings. Dunno if this applies to a 100 as well.

Posted by Mike Renlund (Member # 4675) on 03-03-2015, 12:01 PM:

You can set the DSS100 motherboard time via the BIOS just as you can on the DSS200.

Power off the DSP100.

Reboot the DSS100 and tap the DEL key during the initial start-up of the unit.

You will be taken to the BIOS. Change the time to be correct. Then save and exit the BIOS.

Allow the DSS100 to fully boot into Show Manager.

Power up the DSP100 and let it connect to the ShowStore.

This should set the correct time on the system.

Mike Renlund
Dolby Laboratories

Posted by Steve Guttag (Member # 268) on 03-04-2015, 06:41 AM:

Please note...the BIOS time is UTC time so you should NEVER need to adjust hours unless it is way off time (hours off).

Note too, the DSS100 can go up to Dolby 4.7.3.3 which has a vastly improved NTP results (not that NTP has been improved but how the DSS100 uses it). As such, if you set up the DSS100 to use an NTP time server on system 4.7.x.x, you'll find drift never happens. Another thing to do is it also make sure that the "secure time" is also set to proper time (projector must be on to set it).

Posted by Michel Pomerleau (Member # 7117) on 03-04-2015, 08:32 AM:

The DSP100 have the right time but the Showmanager have the wrong time. But the show start with the Showmanager time.

Posted by Steve Guttag (Member # 268) on 03-04-2015, 03:19 PM:

Right...so just set the BIOS time and you'll be all set. Again, if you get an NTP source on it...it won't drift either.

If the DSP100 time is right...rebooting the server without an NTP source should set the DSS100 since it will get its time from the DSP100 if the NTP server is not present.

Posted by Michel Pomerleau (Member # 7117) on 03-04-2015, 07:15 PM:

The time on the Bios was ok for the min but the Hour was Universal time. so I've only save it as is, reboot and now it's perfect
now same time on both DSP100 and ShowManager.

Thanks

Posted by Marco Giustini (Member # 4544) on 03-05-2015, 02:28 PM:

Steve/Mike,

I thought the secure clock of the media block had priority on the BIOS clock? If no NTP is found the system clock is then initialised using the DSP100's clock and the BIOS one is basically ignored - just used to set up the system clock when the system boots up.

Posted by Mike Renlund (Member # 4675) on 03-05-2015, 08:39 PM:

Marco,

If the ShowStore clock has drifted outside the range that NTP allows (trying to get time from the Media Block or other NTP source), then the ShowStore clock will stop syncing to the NTP source. That sounds like what has happened here. By making the manual adjustment to the motherboard time, the overall system will stay on time.

Mike Renlund
Dolby Laboratories

Posted by Marco Giustini (Member # 4544) on 03-06-2015, 01:26 AM:

Hello Mike

If not mistaken the script executes a 'ntpdate' at startup which syncs the system time no matter what. Then ntpd is started (and that cannot adjust over a much more limited range indeed). ntpdate has a max range as well but 5 minutes are definitely OK. I thought in these cases the only solution was to set up an NTP server?
Thanks

Posted by Mike Renlund (Member # 4675) on 03-06-2015, 10:31 AM:

The time syncing definitely improved over time but there were periods where it did not work well (not sure which version Michel is using). 4.7.3 is the furthest you can go with a 100 series system and has good time syncing.

The other Dolby servers (DSS200/220) and Show Libraries can take system 4.8. We made some major changes there and the time syncing is improved quite a bit.

Posted by Steve Guttag (Member # 268) on 03-06-2015, 11:47 AM:

I'd agree...the biggest improvement happened in 4.7.x.x. There were still a few specific servers that seemed to have a hard time (I'm guessing their internal clocks were less accurate to begin with)...4.8.2.x seemed to take care of them. The DSS100 series seemed to start with more accurate clocks to begin with. Now the CAT745...that is another story. Its "clock" sucks and doesn't sync via NTP. Note, the problem with it is seemingly when it is on battery power.

Posted by Vegard Olsen (Member # 8102) on 03-09-2015, 03:39 PM:

It's beyond me that a solved problem like time can be so hard to get right. In this regard Doremi has been miles better than Dolby. System clock == secure clock. 6 min drift per year as per DCI, extended to 30 min with license. NTP works.

Posted by Steve Guttag (Member # 268) on 03-09-2015, 04:25 PM:

GDC tried to do the system/secure clock being one and the same...didn't pass DCI muster.

I don't have a problem with there being two different clocks at all. The secure clock really only makes a difference to keys...hence the restriction on how far one can set it. The show clock should really be precise to local time. Why they both can't use NTP to keep dead on is beyond me and why something that is "figured out" like NTP and time had to be such a struggle.

Posted by Marco Giustini (Member # 4544) on 03-09-2015, 04:33 PM:

It's the way NTP has been designed. It's a protocol designed to keep your clock synced down to the MILLISECOND (I believe it is a requirement for some database). To achieve that it is very fussy in terms of several aspects of its setup and its sources.
That is one of the reasons why 'ntpdate' is used to sync the system at startup: ntpd would not allow that - or it would be much slower and limited in range; ntpdate just steps the clock no matter what. ntpd just does not work like that.

Posted by Leo Enticknap (Member # 534) on 03-09-2015, 05:57 PM:

Vaguely related to which, in one of our theaters we have a DSS200 and a CP650 on the same network. The server put itself forward on Saturday night (i.e. when I arrived on Sunday afternoon, it had reset itself for daylight saving time without my having to touch it). The 200 is 3 minutes fast - I presume, because the secure time in the cat745 to which it's connected is set that way.

Anyway, I then went to put the internal time in the CP650 forward, and discovered that it had also done itself, and was also three minutes fast (i.e. showing the same time as Show Manager). So I'm guessing from this that a DSS200 will automatically adjust the time of any Dolby audio processor it's configured to work with every March and October, which is a nice touch.

Posted by Steve Guttag (Member # 268) on 03-10-2015, 06:47 AM:

I'd be AMAZED to hear that the DSS200 set the CP650's clock. The CP650's command set is "primitive" to say the least and I'm almost sure that it doesn't have any time functions on it. There is no real magic between the CP650 and a Dolby server...you can eavesdrop in on it and see that the DSS just polls it for info...continuously. I'm surprised sound processor companies like USL didn't have an optional CP650 command set to just allow a direct communication between the DSS servers...a moot point now.

Posted by Jim Cassedy (Member # 4115) on 03-10-2015, 10:10 AM:

I've never been able to figure out why the CP-650 has a clock in the first place.

The only practical use I see for it is for time-stamping events in its' error logs.

No?

Posted by Leo Enticknap (Member # 534) on 03-10-2015, 10:50 AM:

quote: Steve Guttag
There is no real magic between the CP650 and a Dolby server...you can eavesdrop in on it and see that the DSS just polls it for info..

It can certainly do a little more than that. If, when you configure the DSS200 (i.e. run the config script), you specify that it's on a network with a CP650, you can thereafter put volume format and level cues in show playlists (e.g. "change format to 88", "change volume to 6.3", which are then executed at the appropriate moment. So the software capability is definitely there at both ends to enable the server to send simple commands to the CP650.

I'm guessing it can control the time as well, because I can't think of any other explanation for it having set itself to the same time as is in the IMB.

Posted by Steve Guttag (Member # 268) on 03-10-2015, 01:50 PM:

Well, yes...I didn't mean to imply that it couldn't also issue the commands it is polling for. But again, very primitive stuff here. It can't send the CP650 to format 88, persay...you can program a button like U1 to be format 88 and have the DSS200 "press" button U1 but again, no magic there. Heck, I have one DSS200 coming via the serial port (same commands...just needed the Ethernet for something else and with the DSS200 stealing the one and only port, it was more convenient to have the DSS200 come in via serial (and a Ethernet to RS232 adapter).

Posted by Marco Giustini (Member # 4544) on 03-10-2015, 05:19 PM:

Leo,
As Steve pointed out the 650 is very basic when it comes to remote control. When you change the volume the DSS is just sending a very basic string of text that tells the 650 to go to that specific fader setting, that's it.
The 750 is very similar but its list of commands allow you to do virtually everything remotely - i.e. change the amount of EQ at a specific frequency on a specific channel. The 650 only allows you to select formats, mute and volume.
The DSS keeps querying the sound processor about it's fader level - and that's how the main screen is updated in real time! [Smile]

It's like if I asked you 'what's the time?" 60 times a minute to display an accurate clock - down to a second! - on a piece of paper!

Posted by Mattias Mattsson (Member # 4308) on 03-10-2015, 07:04 PM:

It would be interesting to figure out if the undocumented part of the serial protocol of the CP650 (i.e. the one used by the setup application) is also implemented for ethernet.

Posted by Steve Guttag (Member # 268) on 03-11-2015, 06:49 AM:

It isn't...I've tried.

Industrious Clock