Major Sync issues

[Simon N]

OK... so I have now tested a variety of ways and had real world reports back from the edit.

Asides from a different issue regarding sync in to the camera which is causing us a headache and have now abandoned to leave just timecode in, we are getting about an 80% success rate with the pix & r3d's being in sync, i.e. timecode for timecode frame matches exactly. The method to achieve this is that we have the camera linked to a lockit ( sync from sound recordists 788T) and the pix set to receive timecode via SDI with a +1 frame offset. This has given us varying results, but basically we achieve the 80% success in clips matching as described earlier.

I have tested this evening, syncing the lockit box from the pix (freerun) and then jamming the lockit to the camera. The results were less sucessful. Out of 50 slates, 23 did not match picture for picture when sync via timecode. The most successful results have been using the first method (lockit box to vamera & timecode to pix via SDI) and unplugging the camera and re-attaching the timecode every 4-5 slates which has increased the success rate to 85%, though to my mind that is still not satisfactory.

I know there is an issue regarding sync into the camera, however I do not know if this is related to the issue I am having. Any further suggestions as to what to try next?

 

[David Cole]

Are you using an HDMI or SDI monitor with the camera that keeps loosing sync? We've been having MAJOR problems with an external HDMI EVF. We actually have to do a "Restore" every time an HDMI monitor has been connected, in order to get genlock to work. Timecode stays solid all the time. We're using a gain-modified Deneke SB-T.

-- David

 

[Simon N]

Our monitors are SDI and we have 2 cameras both exhibiting the same issues. We have had a major issue asides from the one discussed here with genlock into the camera, which manifests itself when the camera is booted up on a fresh power cycle, i.e a battery change where the camera loses all power or disconnected from the mains then re powered, and the camera discovers timecode & genlock already attached. If we power up then attach there is generally no problem (I think - I have tested that many variables over the last couple of days)

 

[Billy Youdelman]

I start a 3 month shoot next week and the final day of testing has thrown up some significant problems.

The post workflow is nailed so there are no options to transcode in redcine or other options.

The workflow is epic shooting r3d's and out of the sdi into a pix 240 recorder to record dnxhd36 for dailies. Sound is being recorded seperately onto a 788t. Both pix&788 have ambient time code boards so that should not be a problem.

We have tried many configurations of timecode varying from camera generating it to 788 generating & pix also. The problem is that if there was a frame discrepancy with every slate then we could set an offset and account for that in the edit. The problem is though that the sync changes from slate to slate.

As an example our latest test is this:

We set the camera as master timecode using time of day. We then attach the pix to the camer via sdi, timecode & sync. We then shoot say 25 5 second clips of a clapperboard. The pix records simultaneously. We then bring the 25 r3d files into premiere ( to test, the production is using Avid). I then sync both the r3d's and the pix mov files. This is what I don't understand. Out of the 25 clips, 20 sync up fine but 5 of them are one frame out. The pix is 1 frame behind for these 5 slates. Of course one solution is to manually resync the rogue slates, however post are reluctant in case it creates any issues down the line.

What I need is for the timecode to sync no matter what which is what should happen regardless of which camer is used? My thoughts are is it something to do with the timing out of the camera, using the old interlaced fields analogy, is the camera outputting a timecode on the wrong"field" dependant upon what moment the trigger occurs? This is only a theory but hopefully someone has experienced this and can
Point me in the right direction.

Thanks

Due to the age of this thread, I'm quoting most of Simon's original post from April, 2012.

I'm on a shoot with four cameras, and we're recording with the DNxHD36 codec on Pix 240s for use in off-line editing.

We had this very same problem. A random number of clips would be out of sync. We tried everything, from replacing the sync generator, to moving the time code out of the SDI feed and into the Pix deck's separate input, to frequently jam syncing the Pix decks while shooting. Nothing worked. Besides the sync errors, some multi-cam clips would not play in Avid's quad split mode, and Avid's match frame function (go to the same frame in the source clip that's currently displayed in the cut program) would also occasionally fail.

What seems to have finally solved the problem (I say seems because so far we've only done one week this way) is to jam sync the Pix decks time code, then physically disconnect the time code feed from them. This led to our first perfect week, eight weeks into the shoot, with no sync problems, at all.

So... If you're having this kind of trouble with the Pix deck, give this a try. And, if it works for you, I'd appreciate your posting a note here saying so.

Billy Y..