maxslomoff Posted January 31, 2013 Report Share Posted January 31, 2013 hello, our mixer is generating timecode from a fostex 824. jamming deneke boxes and slates twice a day. using a 702t as backup recorder. our video and audio seems to have a 75% out of sync rate, usually just between .25 and 1 frame. theoretically the deneke boxes should hold perfect sync though. any ideas what's going on here? we are syncing dailies with scratch, and slipping audio to match video timecode. wishing the slate clap would sync perfectly every time. Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted January 31, 2013 Report Share Posted January 31, 2013 Some clarification is needed. It is not clear what is out of sync with what. Are you syncing the sound from the 702t to the video? Are you syncing the sound from the Fostex 824? Multiple cameras (genlocked?)? Depending on what it is you are syncing, if you use the "clap" of the clap slate to sync up does it work for camera? Do you have all your numbers right --- frame rates, timecode rates, etc. when ingesting into Scratch? Quote Link to comment Share on other sites More sharing options...
Richard Lightstone, CAS Posted January 31, 2013 Report Share Posted January 31, 2013 I'm trying to understand your math? If the "offset" between the Camera timecode, the Timecode Slate and the Production Audio Time Code is .25 to 1 frame - that ain't a problem! That is certainly not a "75% offset". First, several questions; - What are the TC frame rates of the Alexa, and the Fostex 824? - What is the TC frame rate of the Denecke slates set to? -What are the TC Frame Rates of Denecke sync boxes set to? Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted January 31, 2013 Report Share Posted January 31, 2013 How is the Fostex referenced? If there's an issue, I'd just drive the Fostex in external from another Denecke box and see if that solves the problem. Bear in mind that shutter angle and refresh rates of the on-screen readouts of the slates can cause a 1-frame error in some cases. My line for 20 years in dailies at Technicolor was, "the visible numbers just get us close; the clap makes it exact." How is the 702t getting timecode? Does it produce results that are different from the Fostex? Is the camera getting both genlock reference and timecode, or just timecode? How are the dailies being synced up? There's a lot of factors here that we don't know. Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted January 31, 2013 Report Share Posted January 31, 2013 There's a lot of factors here that we don't know. Exactly. None of us can give any good answers without a lot of questions being answered first. Sorry. Quote Link to comment Share on other sites More sharing options...
Philip Perkins Posted January 31, 2013 Report Share Posted January 31, 2013 In our world, re sound/picture sync, between a quarter frame and 1 frame of error is considered success. philp Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted February 1, 2013 Report Share Posted February 1, 2013 That's what I think, Phil. Especially if it's consistent that close for a long period (like 12+ hours). If there's an accumulative error, like gaining a frame every few hours, then I'd be concerned. Quote Link to comment Share on other sites More sharing options...
maxslomoff Posted February 1, 2013 Author Report Share Posted February 1, 2013 we are syncing the mix track recorded on the fostex to the video the 702T is getting TC from the fostex via hardwire, and is recording a backup mix the deneke boxes are jamed by the fostex, and then wired to the cameras the slates are jamed by the fostex all the framerates are right. all gear is set to 23.976fps the cameras are not genlocked we are syncing the clap of the slate, not the numbers on the slate when i say 75% out of sync rate, i mean 75% of the clips are out of sync in this fashion i've heard the deneke box should drift less than 1 frame in 24 hours. i'm not sure if we have a drifting problem, or a tc offset problem though. i've also heard different gear has more or less reliable clocks than others... can i give you any other info? Quote Link to comment Share on other sites More sharing options...
Philip Perkins Posted February 1, 2013 Report Share Posted February 1, 2013 Ok....what cameras? How long are the takes? philp Quote Link to comment Share on other sites More sharing options...
BWilson Posted February 1, 2013 Report Share Posted February 1, 2013 I'm not sure that the fostex has stable timecode. When I used my PD606 I would jam to it of a lockit, and use the lockit as the master. Quote Link to comment Share on other sites More sharing options...
Glen Trew Posted February 1, 2013 Report Share Posted February 1, 2013 I'm betting the Fostex system of stamping a 48.048k file as 48k and automatically bumping the selected TC frame rate by .1% when selecting 48.048 (call "F Mode" by other manufacturers) is the cause. Quote Link to comment Share on other sites More sharing options...
Charlie Parra Posted February 1, 2013 Report Share Posted February 1, 2013 I'm not sure that the fostex has stable timecode. When I used my PD606 I would jam to it of a lockit, and use the lockit as the master. I'm betting the Fostex system of stamping a 48.048k file as 48k and automatically bumping the selected TC frame rate by .1% when selecting 48.048 (call "F Mode" by other manufacturers) is the cause. I have a hunch that it is a combination of BWilson's and Glen's suggestions. Quote Link to comment Share on other sites More sharing options...
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