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NAGRA 6 timecode correction Tool + Thesis

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Well it has been 8 years since i made my thesis on the Dutch Film Academy about sync sound, but i thought maybe for some,  it can still be of any use.


Let me first say that i am not aware of  any firmware fixes to this problem. so test it for yourself. i did not used a Nagra for 7 years.


When i did one of my films in my exam year we used all kinds of different recorders. A Cantar X2, a few SoundDevices and a Narga 6.

when i received my linked audio and imported it in Pro tools i noticed some really weird behavior.
The beep was perfectly sync but i noticed some of the audio being async. while others where perfectly synced. i also noticed that the regions started and stopped on the right places. BUT.  some audio was shifted within the region so it seemed.

I decided to try to figure out what was happening and make my thesis about Sync sound and especially what happened in this case. The thesis is in Dutch so i try to explain in short what it was all about. 

In short. this is what we used 8 years back in that particular exam year. (2011)

The edit suite that also was used to sync the audio was AVID.

We used EDL to be able to link to  the original audio in Protools (yeah i know its different now)


In the thesis i ran the whole shebang with test files and used perf slip sync to sync all the varieties that existed in AVID. since it yielded the best accuracy.   Since we used EDL perf slipping in 1/3 or whatever frame, it did not really matter in the end since EDL was frame based.... anyhow intention was good :)
I showed what happend with the files when using perf slipping and using an EDL to link or when another method was used.  When do audio files move over etc. 

But the biggest problems was still WHY where some files async within a region ?

In short. The Narga 6 seemed to be the only recorder starting to record whenever you push the record button. thats nice, so you think. 
But it means it starts sample based. the time code only counts frames. so what you will end up with a recording time (according to timecode)and some rest samples (samples after midnight). all other recorders waited for a full frame before starting to record, or they rounded it of to full frames (so the amount of samples can always be divided by how many samples fit into a whole frame, depending on frame rate chosen) so a file has a perfect time code no rest samples left. 

When not using a sample accurate based linking of files this rest samples will be rounded off and will be an offset within your region. (so it looks perfect, but in fact you audio starts within the region to soon or to late depending on how many rest samples left)

So i thought  i might be able to write a small JAVA program that used the BWF executable to load the audio files and remove the rest samples so linking can be done accurately, just like recordings made with all other recorders.

Thesis is in DUTCH and the small Java program i wrote can be downloaded here, it was tested on windows and mac but you need to have java installed !
It has been a decent amount of time ago , so i am a little rusty on the subject. but feel free to use the software at your own risk. !!!!!


DOWNLOAD

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I've never noticed this phenomenon nor had post ever bring up the subject to me, although I suspect it could have simply been missed, as most of my recordings with my VI were classical music or simple dialogue, where a minor slip could sneak by.  I've always used pre-record on my VI, do you think that this could affect the file record start issue?  So if pre-record were enabled that it would round to a nearest whole unit of time in the pre-record buffer?  I've since replaced my VI with an X2, so it has sat unused for many years now (for sale if anyone interested), but I do miss the very flexible monitoring capabilities of the VI.

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3 minutes ago, Tom Visser said:

I've never noticed this phenomenon nor had post ever bring up the subject to me, although I suspect it could have simply been missed, as most of my recordings with my VI were classical music or simple dialogue, where a minor slip could sneak by.  I've always used pre-record on my VI, do you think that this could affect the file record start issue?  So if pre-record were enabled that it would round to a nearest whole unit of time in the pre-record buffer?  I've since replaced my VI with an X2, so it has sat unused for many years now (for sale if anyone interested), but I do miss the very flexible monitoring capabilities of the VI.

Thats a good one ! i never tested pre record vs normal. as far as i remember all Nagra files had a sample count that could not be divided by the amount of samples that are in a full frame.  and yeah the offset is small. but i did notice it especially since i had a scene where someone got slapped in the face :) haha and it was awfull. i was like wtf is this ?    i went straight to the editor :) but it was not her fault.

the annoying thing was it became a floating sync. since  sometimes it was to early sometimes to late. and everything in between. so fixing was almost impossible.

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