SRW Deck Locking/Syncronizing (not what you think)
I'm new to this site so just wanted to say a brief hello. From reading through some of the responses on this forum it seems there are many knowledgable people who may be able to answer this question that I've been having a hard time getting a straight answer about.. Here is my unique situation.
I'm a cinema engineer and rarely deal with broadcast type equipment except for the two SRW 5100 decks we own. We regularly use them for playback of premeires and screenings of feature films and TV shows through our projectors when the client requires them instead of a digital cinema (DCP) server.
In this particular case I have a film which is 23.98Psf 4:4:4 which is well over the capacity of a single HDCAM SR tape at over 2:45 minutes long which has forced the post team to split it across two tapes. What I need to do is make a seemless changeover between tapes while the program is playing, similar to how we used to make a changeover on 35MM film between 20 minute reels. I will be switching the video with a switcher like a Folsom or similar. To do this without any program video interruption I am trying to somehow lock the decks together (specifically the LTC Timecode) somehow so that when I start the second tape on the second deck it is playing at the EXACT same time, down to the frame. There is about 30 minutes of overlap between the two tapes (meaning the second tape starts with the Timecode and specific scene that is about 30 minutes before the end of the first tape) and the LTC Timecode on the second tape starts at the specific spot where that part of video starts (let's say 03:10:15:00 for example) not back at 01:00:00:00 where the first tape starts.
I'm not sure if this is even possible with these decks, or if there is a better way to accomplish this, but that's why I'm here.
Another question I have is about Timecode output.. For reasons I won't go into there is also going to be a protools rig synced to my Timecode output from the deck for a different part of the show. Being that I'm making a switch between decks the plan as it stands is to physically switch the Timecode feed from deck one to deck two when I start playback from deck two using an xlr A/B switch. We've tested this and it does work, but there is about 10 seconds when the switch is made that protools loses sync and has about a 5 second delay before it re-syncs to the second deck. It's not the end of the world for the purpose it is being used for, but is there any way to take a Timecode feed that could stay continuous throughout the whole program even with the switch from deck one to deck two?
I would love to hear any thoughts you all may have on this. I realize it's a pretty unique situation but any thoughts are greatly appreciated!
If two decks need to be synchronized by timecode, this can be done only if the code matches on both and you can roll in. For example, I used to have to work on a show that had its split tracks laid out over 8 tracks of DigiBeta (2 tapes). If I wanted to load all 8 tracks at once, I could patch RS-422 between the decks, set up one as Master and one as Player, and arm the Cue track, then enter a common in-point on both decks and hit Preview Edit, which would preroll to 5 seconds before my in-points, and by the time it hit the in-point, both decks would be playing in sync with each other for the duration. That is the only way to get these decks to play in sync without some kind of external synchronizer. That said, my method above would not work for you, so you need to look into if an external synchronizer can perform the speed cal and lock for both machines, having programmed each machine's start time and sync point. I would think this should be able to be achieved, but I am not sure, since I've never had to do it. I would contact people at JL Cooper, who make a synchronizer that might do the job.
Thank you, Mark! I was thinking along those lines, I just wast sure of a specific company who made them. Everyone I talked to mentioned an external unit but didn't happen to actually MENTION one of them. I will check them out and let you know how it works. As far as the tapes, the time code is the same on both as far as being matched to the same frame of video on each, but the second tape doesn't start at 1:00:00:00 like the first in order to make room for the last half hour of the film. I believe the second tapes LTC is somewhere around the 1:45:00:00 mark...
If there is a thirty minute overlap, you have a much easier method you can use. Your ears. Synching two VTRs by ear is something folks have been doing all the way back to the 2" Quad VTR days. Just have a speaker for each VTR cranked to a reasonable level, this assumes you are operating the machines in a separate room from the audience of course. When you reach the overlap point on the first VTR, synch the second machine up via a word or picture cue, or even via timecode, manually. If the machines are close, you will hear almost an echo or reverb. Then you can, by hitting the PLAY button and either the "+" or "-" button, bump the second VTR forward or backwards 1 frame at a time till the echo sound goes away. When the echo goes away, the two VTRs are in synch. You may also be able to do it by holding play and then moving the shuttle/jog knob clockwise or counterclockwise. Different VTRs have different methods of doing this frame bump, and I believe my first method was one way for the SRWs. Any decent operator can do this within a minute or so. Yes, it does take a bit of practice, but it really is a tried and true method.
One specific note about the SRW's... the methods I mention above may work only in the home menu or the cue menu. I don't remember which. I used to have to do this with SRWs a few years ago on a once in a while basis, and I remember it would work only if I was on the right menu page.
M. Scott Cole
Senior Post Production Editor
CBS News, NYC