C100: C100 Audio Sync Issues

[SWIF Studios]

I have a 20 min clip recorded with the C100 at 24p and the audio was recorded externally using a Zoom H6 at 48kHz (running audio directly into the C100 was not an option at that moment). When I try to sync the 2 together, the audio and video slowly drift apart and fall out of sync. What gives? Anyone able to shed some light on what I may doing wrong?

My setup was 1 Canon 5D MKIII recording externally to the Ninja Blade / Canon C100 / short clips recorded to the GH4 and my main audio source recorded to a Zoom H6. As far as the Ninja and the GH4 are concerned, these cameras appear to be syncing up nicely with Zoom H6 audio, but they're only short clips so possibly also out of sync. My C100 was recording for longer durations and the syncing issues are very noticeable.

Thanks!

 

[ReelWorksMedia]

I have a 20 min clip recorded with the C100 at 24p and the audio was recorded externally using a Zoom H6 at 48kHz (running audio directly into the C100 was not an option at that moment). When I try to sync the 2 together, the audio and video slowly drift apart and fall out of sync. What gives? Anyone able to shed some light on what I may doing wrong?

My setup was 1 Canon 5D MKIII recording externally to the Ninja Blade / Canon C100 / short clips recorded to the GH4 and my main audio source recorded to a Zoom H6. As far as the Ninja and the GH4 are concerned, these cameras appear to be syncing up nicely with Zoom H6 audio, but they're only short clips so possibly also out of sync. My C100 was recording for longer durations and the syncing issues are very noticeable.

Thanks!

Did you have your bit depth set the same on all units? Just curious. The H6 is usually fairly good with drift. That said, these units are not clocked...so you could get some drift. I have done interviews that long without problem on these units though. How bad is your drift....a few frames?

 

[bengiles]

Any kind of drift within a 20 minute window is odd, I'd say. I haven't even heard talk of audio drift for well over 10 years (it used to be an issue with some DV sources way back when.)

Based on what you're saying above, and you had absolutely no breaks in the recordings, my guess is that it's an NLE timeline issue. Are you using something like Premiere or FCPX and just chucking everything on the timeline?

Were you running different sample rates? Was your Zoom set to 44.1, while the C100 ran at 48, for example?

If so, try sample rate converting all of your audio to the same rate.

Let us know if that improves it.

Ben.

I have a 20 min clip recorded with the C100 at 24p and the audio was recorded externally using a Zoom H6 at 48kHz (running audio directly into the C100 was not an option at that moment). When I try to sync the 2 together, the audio and video slowly drift apart and fall out of sync. What gives? Anyone able to shed some light on what I may doing wrong?

My setup was 1 Canon 5D MKIII recording externally to the Ninja Blade / Canon C100 / short clips recorded to the GH4 and my main audio source recorded to a Zoom H6. As far as the Ninja and the GH4 are concerned, these cameras appear to be syncing up nicely with Zoom H6 audio, but they're only short clips so possibly also out of sync. My C100 was recording for longer durations and the syncing issues are very noticeable.

Thanks!

 

[Michel]

The c100 24p is actualy 23.976fps so youre NLE should be set to 23,976fps
The samplingrate of the audio doesn't affect the framerate a sec of sound = a sec of sound
If the ninjablade was set to true24p (if that is possible) then you'll have a problem and either the 5d or c100 will be out of sync

 

[bengiles]

The c100 24p is actualy 23.976fps so youre NLE should be set to 23,976fps
The samplingrate of the audio doesn't affect the framerate a sec of sound = a sec of sound
If the ninjablade was set to true24p (if that is possible) then you'll have a problem and either the 5d or c100 will be out of sync

Sorry, I missed the 24P reference - I think Avian's nailed it.

You may have to slip the synch on anything that's straight 24P (dunno about the Ninja 24P spec), as long as the shots aren't too long.

 

[SWIF Studios]

Thanks everyone for your help! Thanks Avian, I have my timeline set to 24p and had no idea the C100's 24p is actually 23,976fps, thanks for that. Is there a way with After Effects to convert my 23.976 footage to true 24p?

 

[SWIF Studios]

Ok I think I've got it figured out... I've managed to conform my clips in AE to 24p. Too bad the C100 doesn't give you the option for true 24p. Thanks for your help everyone.

 

[sonofaresiii]

Any kind of drift within a 20 minute window is odd, I'd say. I haven't even heard talk of audio drift for well over 10 years (it used to be an issue with some DV sources way back when.)

Based on what you're saying above, and you had absolutely no breaks in the recordings, my guess is that it's an NLE timeline issue. Are you using something like Premiere or FCPX and just chucking everything on the timeline?

Were you running different sample rates? Was your Zoom set to 44.1, while the C100 ran at 48, for example?

If so, try sample rate converting all of your audio to the same rate.

Let us know if that improves it.

Ben.

Going solely off what I've heard, the zoom recorders are notorious for drift. I've never had a major problem with it personally but I've heard lots of stories of dramatic drift after even ten minutes.

 

[Michel]

Going solely off what I've heard, the zoom recorders are notorious for drift. I've never had a major problem with it personally but I've heard lots of stories of dramatic drift after even ten minutes.

Sound doesn't drift it is always! the video that drifts, or to be more exact the NLE timelinesettings versus the camera fps

A soundrecorder records 1 second of sound in a second, it can't capture more or less. it doesn't do frames/sec it captures it all.
Only in the analog days when recording on tape you could get timing diffrences when the playback player run at a slightly different pace as the recorder did.

On prof sound recorders there is a frames/sec setting but that relates only to the timecode wich should be set at the same speed as the camera.

This problem is probably more comon in non PAL countrys because of your stange (not true) framerates 23.976fps = 24fps?? and 29,.... =30fps versus the also possible true 24fps and 30 fps settings.

 

[Run&Gun]

Ok I think I've got it figured out... I've managed to conform my clips in AE to 24p. Too bad the C100 doesn't give you the option for true 24p. Thanks for your help everyone.

Hmmm... The C300 has the ability to shoot true 24. Maybe it's in a menu somewhere. Or it's just something else Canon uses to separate the models... But, if you're here in the US, unless you're doing a "film out", why would you need to shoot true 24? More than likely it would just cause more problems.

Something to think about, too(not saying that this IS your problem), TC can be complicated these days. Some pieces of gear run their TC at 29.97 even though you're shooting 24(23.98). The first time I shot with a C300(borrowed a friends before I bought mine), we used it on a multi-cam interview with my two Panny 2700 P2 VariCam's and SD 664. I had a hell of a time trying to jam everything. Part of it was not knowing the C300 and part of it was not knowing that the 2700's only run 24(23.98) frame TC under very specific(and few) combinations of framerate, resolution and codec. There is actually a spreadsheet type grid in the manual laying out what it outputs and records for TC and video signal formats from the SDI outs under all the different combinations/settings that the camera is capable of doing. The C also has a setting(Normal or XF Legacy) that switches the TC from 30/59.94i(legacy) to 24/23.98(normal).

Luckily I had time to figure it out before we stated rolling, but the combo of the 2700's actually outputting TC at 29.97 TC(even though we were shooting native 720/24) and the SD 664 TC set to 23.98 and the C300 set incorrectly made for a frustrating time before the shoot.