More Dublinites, or Dubliners... Dublonians? Anyway Thanx Senior Bloom!!!
- Thread starter Rakesh Jacob
- Start date
Uwe Lansing
Veteran
Eddy Robinson
Well-known member
Just FYI, all audio recorders (not just the zoom) record at a speed indicated by the sample rate - typically 48Khz. The frame rate is just metadata. The only exceptions are on pro recorders with a pulldown option, where the record or playback sample is modified by +/- 0.01%. You would engage this (down) if you knew the final output was going to be film or if you were doing playback for a music video (up). But generally the picture frame rate is not baked into the audio itself in any way.
This only matters if you need to maintain separate workflows for film and video, where the theatrical 24fps but the video frame rate is 23.976. In general you should set everything - camera, audio recorder, NLE - to 23.976 and then forget about it. If you are lucky enough to make a film which is sold commercially the distributor will pay for the conversion.
None of this is an issue for people in PAL-land, where 25fps means 25fps.
Michael Olsen
Veteran
Man! They have the metric system, too. It's just not fair.
As amazing as film?
Sorry I'm a bit thick. I've done a bit of recording, but I've never run into a recorder where I've noticed that I could select 23.976 or a 29.97 setting, but then again I've never had to look for it. So just to be clear, the zoom H4N will let you select 23.976 or 29.97 recording speed? ...and then select 24bit 48 KHZ and I'm good to go right?
Also, when doing a music video, can I just put the redbook 44.1 16 bit CD track on the time line and have it sync up right after having the artist lip sync to it while filming. Thanks ....also thanks Tim
Tim Joy
Veteran
I'm only talking about the H4n, and from testing and my background, I'll te it will sync with any video cam that records at frame rates of 29.97, 23.976... etc. The Zoom does not have an adjustment to switch from 29.97 to 23.976 or any other frame rate, and I believe, although haven't tested anything other than 48k, that it does not matter what sample rate you record at.
Hmm. Possibly the european version of the Zoom will sync out the the box, but if it doesn't, you would probably just conform the audio file from 29.97 to 30.000. Don't hold me to that. Best guess.
No adjustments for frame rate on the H4n. Yes, 24bit 48k and you're good to go.
The 44.1 music... I would need to test that, but I think it would sync up right.
What thread was this again?? :grin::grin:
rogar-Evil(DBG):
Ian-T
Veteran
I keep reading or hearing about the zoom not syncing properly with recorded video and I always found that to be strange. There shouldn't be any reason whatsoever for a device like the zoom to slide off course when playing back UNLESS of course either the zoom or the camera itself PLAYS BACK at a DIFFERENT speed than it recorded ( that to me is some sort of manufacturing defect). I also believe that if you change the sample rate it can also possibly affect playback. For example...if something recorded in 24 bits but played back in 16 bits then there might be a slight shift (Might). IMHO
ydgmdlu
Veteran
Yes, that does sound rather nonsensical... If you record exactly ten minutes and 21 seconds of video, along with exactly ten minutes and 21 seconds of audio, then they should sync properly, regardless of the frame rate or sample rate, unless they change during playback or editing.
Eddy Robinson
Well-known member
If you're shooting video to output video, yeah. If you were shooting the music video on film (which was the case for any pro work until quite recently), then the conversion to video would throw the lip sync off slightly by the end of each take.
In those cases what (used to) do was get a copy of the song on DAT and play it back 0.01% faster than normal during shooting, then use the normal speed audio during editing, because the image playback gets slowed down by the same amount during telecine.
There's an exhaustively complex explanation here; the short explanation is that back in 1953 the broadcast frequencies in the US were tweaked slightly to make color TV transmission easier. This system has persisted so long that they've actually stuck with it for digital TV transmission to ensure backward compatibility with old equipment.
Rakesh Jacob
Veteran
Sorry for the hit and run post, I don't know if any one touched on this 'cause I don't have time to back track. In the middle of negotiating with stupid suits over a budget that's allready too low, and I'm trying to decided should I call on my inner divine nature and work through it or summon some couRAGE and tell them to F---OFF!
Anyway the problem people have with 5D audio syncing is cause the 5D tags are misslabled as 30p isntead of 29.97 so the NLE plays it back too fast. If you slow down the 5D footage to 99.9% (I believe) it works out a lot better
Anyway the problem people have with 5D audio syncing is cause the 5D tags are misslabled as 30p isntead of 29.97 so the NLE plays it back too fast. If you slow down the 5D footage to 99.9% (I believe) it works out a lot better
Last edited:
Michael Olsen
Veteran
Sorry, I'm daft.
If I record at 23.97 on the 7D and set the Zoom H4n to the 23.97 speed, will I need to do any adjustments in post to prevent slipping, or will everything line up real nicelike?
Again, apologies for my thick-headedness.
If I record at 23.97 on the 7D and set the Zoom H4n to the 23.97 speed, will I need to do any adjustments in post to prevent slipping, or will everything line up real nicelike?
Again, apologies for my thick-headedness.
Ian-T
Veteran
Ahhh...now that makes sense. Then this should be something that's unique to the 5Dll only and not most other cameras.
Anyway the problem people have with 5D audio syncing is cause the 5D tags are misslabled as 30p isntead of 29.97 so the NLE plays it back too fast. If you slow down the 5D footage to 99.9% (I believe) it works out a lot better
Ian-T
Veteran
It should work with no problem on 7D footage. It seems like from what Johhny Cola is saying that the 5Dll's frame rate is being incorrectly read within most NLE's. This is because it (Canon 5Dll) uses a non-standard frame rate that NLE's don't quite understand. So they pick the closest match which throws EVERYTHING off (no pun intended).
Michael Olsen
Veteran
Ah, didn't read Mr. Cola's post. Thanks. :beer:
Audio recorders don't have framerates people. (Well... unless you count 48kHz as a "framerate").
10 seconds of audio is 10 seconds of audio, no matter if the camera is 18fps, 132fps or any other fps.
Audio drifts appear when:
A) Video isn't played back at the same speed it was shot. (either because of a problem with camera/NLE or on purpose -- i.e overcrank/undercrank for slomo/speedup)
B) Audio isn't played back at the same speed it was recorded. (for instance if the clock in the audio recorder is off and records really at 47978Hz when it thinks it records 48000Hz)
-X
10 seconds of audio is 10 seconds of audio, no matter if the camera is 18fps, 132fps or any other fps.
Audio drifts appear when:
A) Video isn't played back at the same speed it was shot. (either because of a problem with camera/NLE or on purpose -- i.e overcrank/undercrank for slomo/speedup)
B) Audio isn't played back at the same speed it was recorded. (for instance if the clock in the audio recorder is off and records really at 47978Hz when it thinks it records 48000Hz)
-X
Michael Olsen
Veteran
I clearly need to read up on audio so I can be a proper soundo.
What would Jesus do? Yeah.... I'm thinking jesus would pretty much tell them to F--- Off. Buddha on the other hand was a pussy, and would do it for free. I'm thinking somewhere in between would be good.
Thanks so much to Eddie and Tim for helping me with my stupid questions here in the Dublin audio sync thread!
Eddy Robinson
Well-known member
No you won't, yes it will
Don't apologize, everyone who is not a broadcast engineer hates this. Walter Murch has a multi-page rant about it in his book on editing.