Film-Tech Forum ARCHIVE: DTS track slow to start.

This is topic DTS track slow to start. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Rob J. Buskop (Member # 3338) on 08-07-2008, 11:21 AM:

A while ago a lab printed a missing piece of entr'acte music for a film in our archive.The DTS timecode from Rl. nr. on the disc combined with SR analog track. So far so good. But when checking it out in DTS only (bypassing the opt. reader) it skipped about
4 seconds from the beginning of the music. So in DTS mode the sound came about 4 seconds after the orchestral piece had started.
Hereafter all was fine.
When laced through the optical reader as well, the first opening chords were there, whilst it was apparent that after a few seconds it switched over to DTS.
Could this have something to do with the spin up time of the disc or should there be some special timecode info in front of the actual code that relates to the start of the music?
The only thing I can think of is a time lag between the first info that's been read and the delivery. Any ideas on this? And
would there be a solution to get rid of the SR beginning and have the whole start in DTS as it would have worked before some
projectionist tore the original play-in off?
Any suggestions will be highly appreciated!
Thanks,
Rob.

Posted by Chris Slycord (Member # 4239) on 08-07-2008, 11:29 AM:

Sounds like the beginning has a bad/missing DTS time code, possibly.

Posted by Darryl Spicer (Member # 711) on 08-07-2008, 11:35 AM:

It sounds to me like the delay is caused by the DTS unit storing up to four seconds of information before kicking in so it can have that 4 seconds advance info for time code dropouts.

Posted by Rob J. Buskop (Member # 3338) on 08-07-2008, 12:46 PM:

Thanks, guys. But it's not missing or poor coding. The green
light goes on and then it takes a little while.
I myself think about the DTS "waking up" and then it has to spin up to locate the position where it wants to be. Remains the question what to do about it or what to splice in front of the newly made footage..... or what..!

Posted by Marco Giustini (Member # 4544) on 08-07-2008, 01:54 PM:

Is the missing piece at the beginning of the reel? In my experience, if you start a movie in a point different from the reel head the DTS player will take few seconds to lock.

Or, the DTS can be in sleep mode. After 30 minutes the drives stop spinning and it takes about 2 seconds to be ready again.

Marco

Posted by Brad Miller (Member # 2) on 08-07-2008, 02:33 PM:

Generally when I have seen this it is because the projectionist didn't cut the film at the "3" on the countdown, and instead cut at the "0" or at a visible frameline. It does take the dts a second to start playing, hence the "lead in" black from the leader shouldn't ever be cut off.

Posted by Rob J. Buskop (Member # 3338) on 08-07-2008, 04:53 PM:

Hi Brad, well it should be something like that. The question
now is how to cure it in some cunning manner.
It seems to me that, following this line of thinking, something
should be spliced in ahead of the newly printed play in to get
the DTS system in a sort of "primed" position.
Sadly there's no original leader. Have checked if the ROM player
reacts to the 0 signal ----- code to start it spinning at least
but that does not happen. Anyway it's difficult to imagine that within this very short period of the first time code being read everything should react immediately. But....when you would put
the original reel on it would not show this slightly delayed start...So what can one do to activate the system just before the first time code is read?

Posted by Marco Giustini (Member # 4544) on 08-07-2008, 05:45 PM:

It's not an "activate the system" issue.
On my demo reel I have some scene from the last 007. The player starts few seconds late since the beginning of the reel is missing (I spliced only a part of the reel).
If it's not a "player idle" issue I think you cannot cure this.

Marco

Posted by Bruce Hansen (Member # 281) on 08-07-2008, 06:10 PM:

If the original leader has been cut off and the DTS time code starts at "0" count down, that could be your problem. The player does not know what you are going to want to play, so when it sees the first bit of time code, it must go find that time code on the disc. This can take several seconds.

If the original leader has been cut off, try this, it may help a little: attach the leader from a trailer that has DTS time code on it, to the beginning of your film. This may give the DTS player a little "kick", so that it will find the time code you want faster.

Posted by Marco Giustini (Member # 4544) on 08-07-2008, 06:25 PM:

There should be something different at the beginning of the timecode. The Player has no problems at all locking as the splice run if you cut properly the leaders...

Try following Bruce's way, but be sure that the beginning of the trailer is not played back instead of the movie's start [Smile]

marco

Posted by John Wilson (Member # 269) on 08-07-2008, 06:35 PM:

Try putting a dts tag on the head and see if it runs from the start of your music then. If not, the time code's not there. If it is, then you can just switch into it after the tag has gone through.

Posted by Blaine Young (Member # 3992) on 08-08-2008, 12:24 AM:

If you can post an image of the first 3 or 4 frames of the film in question, we can determine what your first viable DTS frame is. That will give us an idea of how much film is missing. If the timecode is simply too far into the program, you will have to live with the first part playing in SR.

Posted by Rob J. Buskop (Member # 3338) on 08-08-2008, 04:57 AM:

Thank you all for your greatly appreciated thoughts on this matter! I think Bruce's idea of putting a DTS tag in front is worth trying. Will report on the result.
The suggestion of posting pictures of the first frames with TC is probably not very enlightening because it's play-in music, so there are no frames. Everything is black, apart from the soundtrack. Anyway I'll try to add a picture...!

Had to reduce the size to the absolute minimum, so what was nice nad clear does'nt make much sense anymore now..... Sorry.

Posted by Blaine Young (Member # 3992) on 08-08-2008, 11:58 AM:

Unfortunately that isn't as high a resolution as I need. A close-up of the soundtrack area with the DTS Timecode will help. The image area is not important for this.

Posted by Warren Dewey (Member # 3609) on 08-09-2008, 07:29 AM:

There is a similar problem with the 1998 restored Wizard of Oz we are playing now. There are no splices involved-- reel 1 opens with the silent "new" Warner Burbank Studios wavy aerial shot logo, fade out, then fade in the 1939 lion. The lion's roar cuts on about 2 seconds late, even though our dts usually locks up fairly quickly.

The print has SR and DD tracks from the leader, but the dts track does not start until the "new" section is almost faded out, about 2 feet before the lion. There are about 6 frames of white dashes, then code. You definitely get the feeling a buffer is filling up before the sound comes on (??)

If there originally was dts material before the first logo, like a tag or trailer, I suppose the buffer would be ready and start playing immediately-- but the time code would still be missing during the first logo. Not a big deal, I'll just play the lion analog. But is it possible this version can't be played correctly with dts?

Posted by Marco Giustini (Member # 4544) on 08-09-2008, 09:32 AM:

I suppose that DTS gives exact indications to labs on how to print timecode.

I remember when I was showing "Mr&Mrs Smith" in DTS. Despite I cut the leader in the correct point, after DTS logo a tail of something could be heard.
I found then that the US version of the movie was distributed by Regency, if I remember correctly, while in Italy it wasn't. So they just cut the regency logo from the movie.
Unfortunately since timecode is read in advance, the player was able to lock one second before SRD and it played just a bit of the "regency" logo...
I suppose it's not a DTS issue but a lab issue... [Frown]

Marco