Avid Pro Audio Community

Avid Pro Audio Community

How to Join & Post  •  Community Terms of Use  •  Help Us Help You

Knowledge Base Search  •  Community Search  •  Learn & Support


Avid Home Page

Go Back   Avid Pro Audio Community > Pro Tools Post Production > Post - Surround - Video

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 04-26-2007, 10:02 PM
eastwestaudio eastwestaudio is offline
Member
 
Join Date: Aug 2006
Location: New York, NY
Posts: 43
Default syncing DA 88s and HD tapes

forgive me if this has been discussed - i've tried searching thru older posts, and didn't come across anything...

when dealing with an HD project for TV with a time code rate of 23.976, how should one make a da 88 to properly be sync-able to a hdcam tape?

one method i've heard is to playback PT and lock the da88 deck at 24fps. therefore, if a future user needed to sync up that da 88 tape to the hdcam master, they can just select a .1% speed difference on the da 88 deck and the two tapes (time codes) should play in sync.

this seems to make sense to me - i just wanted to hear from a second source that this would work. is this a good method? is this a standard at all?

(the fact is, in the delivery requirements from the network, they don't specify a time code rate for the da 88)

thanks

-greg-
Reply With Quote
  #2  
Old 04-27-2007, 05:25 AM
Richard Fairbanks Richard Fairbanks is offline
Member
 
Join Date: Dec 1969
Location: New York, NY
Posts: 1,861
Default Re: syncing DA 88s and HD tapes

Even though that will work if you are using analog audio in/out, the DA88 deck will be running at 47.952kHz, requiring sample rate conversion to transfer digitally. I would try to clarify the specs before assuming that option!

(For those who don't understand the problem, DA88 decks don't know what 23.976 timecode is. Their hardware is designed to lock at 24fps only. They don't take tri-level sync either, so for HD work they must be locked to timecode or wordclock...which should be 48kHz. Forcing them to lock to 24 frame code running at 23.976 also forces them to run their hardware innards slower, throwing the sample rate down to 47.952kHz. So, the choice is to run them at the correct sample rate, which prevents simple timecode chase-lock at 23.976, or run them off speed, which requires digital sample rate conversion. Personally, I think it is better to run the decks at the correct sample rate. Anyone who works with a standard def downconversion, such as foreign language distributors for the next several years, can take a DA88 tape, set the deck for 29.97 code, and lock up. They could NOT do that if the DA88 tape is meant to be played .1% slow. In short, the network should clarify their spec.)
__________________
Call me by my real name, "Postman"
Reply With Quote
  #3  
Old 04-27-2007, 06:58 AM
Matt Chan Matt Chan is offline
Member
 
Join Date: Jan 2004
Location: Toronto, Canada
Posts: 245
Default Re: syncing DA 88s and HD tapes

we used the downconvert from an F500 deck to sync up 29.97 pro tools sessions to 23.98 hdcam tapes for screenings. could the same method not be used for a da88? we would take the downconvert vitc (29.97) from the composite output of the f500 into our sync io, send ltc (29.97) from the sync io to the da88, and genlock to the composite video signal at the same time.
Reply With Quote
  #4  
Old 04-27-2007, 07:03 AM
minister's Avatar
minister minister is offline
Member
 
Join Date: Jun 2004
Location: Minneapolis, MN
Posts: 4,807
Default Re: syncing DA 88s and HD tapes

hey, that's clever Matt!
__________________
Tom Hambleton CAS
Ministry of Fancy Noises
IMDb
Undertone on Facebook
Undertone Custom Sound Libraries

"Groupable markers would be epochal!"
-Starcrash
Reply With Quote
  #5  
Old 04-27-2007, 11:42 AM
Richard Fairbanks Richard Fairbanks is offline
Member
 
Join Date: Dec 1969
Location: New York, NY
Posts: 1,861
Default Re: syncing DA 88s and HD tapes

Sure! That does the trick. I'm pretty sure a Soundmaster could do it also. One way or another, if you want the DA88 to run correctly with 48kHz sample rate you have to convert 23.976 code count into 29.97 non-drop, with matching HH:MM:SS.
__________________
Call me by my real name, "Postman"
Reply With Quote
  #6  
Old 04-27-2007, 12:58 PM
Matt Chan Matt Chan is offline
Member
 
Join Date: Jan 2004
Location: Toronto, Canada
Posts: 245
Default Re: syncing DA 88s and HD tapes

yeah i can't remember who told us about it but it works like a charm.
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Master Tapes in Pro Tools. mike1234 003, Mbox 2, Digi 002, original Mbox, Digi 001 (Mac) 9 11-27-2008 03:01 PM
OT – The Clash – Vanilla Tapes Plastik909 003, Mbox 2, Digi 002, original Mbox, Digi 001 (Win) 3 09-03-2004 08:36 AM
Just question about the old 4 track tapes... fabpab 003, Mbox 2, Digi 002, original Mbox, Digi 001 (Win) 4 10-01-2003 09:37 AM
2 tapes, 1 Adat keny 003, Mbox 2, Digi 002, original Mbox, Digi 001 (Win) 5 10-19-2002 12:22 AM
How do you store your data tapes? flymax Pro Tools TDM Systems (Mac) 6 02-02-2002 12:47 AM


All times are GMT -7. The time now is 01:16 AM.


Powered by: vBulletin, Copyright ©2000 - 2008, Jelsoft Enterprises Limited. Forum Hosted By: URLJet.com