I'm handling the technical side of things for Julian on this issue - I was able to reproduce the issue (redescribed below) using two different Scarlets (#503 and #870, build 3.0.7 - firmware was updated using the 'force_' prefix so should have done a complete reset) with two different Ambient Lockits attached.
The setup:
Scarlet-X: 4K HD, timebase 25fps, frame rate 25fps, powered using GlobalMediaPro R-model (RED firmware) bricks. Settings > Setup > GPIO/Sync is set to 'Genlock'
Ambient Lockit ACL 203: set to 1080p/25fps/25fps, supplying both genlock and timecode to the camera using a RED 3BNC-to-000 sync cable. TC, GEN, and SYNC are lit green
x A-box: takes a feed from the sound recordist's mixer and supplies mono/single channel guide audio to be recorded with the R3Ds
The issue:
The camera appears to drop frames on a cycle (the cycle differs between the lockits/cameras), causing a noticeable 'hitch' in the video playback. As the video drops frames, the guide audio gets further and further out of sync (the offboard recorded audio also doesn't sync after aligning by slate or by timecode).
Some examples from both Scarlets (Camera A = #503, Camera B = #870) processed in REDCINE-X to h264 Quicktimes:
http://www.halcyondigital.co.nz/halc...001_0614P0.mov panning test, demonstrates dropped frames/'hitch' in video
http://www.halcyondigital.co.nz/halc...002_0614YK.mov slate test, demonstrates guide audio drifting further and further out
http://www.halcyondigital.co.nz/halc...001_06138K.mov panning test, demonstrates dropped frames/'hitch' in video
http://www.halcyondigital.co.nz/halc...002_0613PK.mov slate test, demonstrates guide audio drifting further and further out
and the log file from Camera B (Camera A didn't generate one as I didn't power the camera down) is
here.
The 'solution':
After unplugging genlock and switching Settings > Setup > GPIO/Sync to 'Off' the issue vanishes. Timecode is left plugged in. TC is lit green, GEN and SYNC are grey.
Whilst genlock is unnecessary for this setup (just timecode is needed for sync sound) and production is continuing it would be good to get to the bottom of this issue as it sounds like what is described
here,
here, and
here.