BWF Timecode Off in FCP, Double-Checked w/ Wave Agent

[Jeremy Garchow]

What format and frame rate?

[Ryan Biller]

The Tascam was set for 48KHz/24bit at 29.97 DF- Broadcast WAV’s of course. Dragging the WAVs right into FCP shows a TC Rate of 30.

Now, it was a Vari-Cam Panasonic and I could use some enlightenment-
The way I think I understand Vari-cam is that the sample frequency for the camera always runs 59.94 and the operator chooses a frame-rate and the camera takes care of pull-up/pull-down.
(If I’ve got some wrong concepts there, I don’t mind so long as someone lets me what right is.)
That said, the cameraman was using 24p for his frame rate and the footage was digitized using Apple ProRes422 1080i and FCP lists the vid rate as 29.97 and the TC rate as 30.

So with regards to the camera and syncing: are frame rate, sampling frequency, and time code rate somewhat independent entities?

Would there have been a better setting for the Tascam? If I had it to do over, I’d have chosen 29.97 ND… but the Tascam has options for 30 DF and ND (and 24, 25, etc) and pull up and pull down for ’em all; seeing the TC Rates in FCP as both 30, I’m left with a lot of wonder.

And does any of this affect the Start TC/Media Start disparity I’ve run into with FCP and the BWFs?

[Jeremy Garchow]

So audio is df and footage is ndf?

You catured 720p to 1080i?

[Ryan Biller]

I am not certain about the footage being non-drop though my suspicion is yes.

There were two shoots for this project: on the first, I thought the cameraman and I agreed to do 29.97 DF as the TC rate just in case it may have a broadcast future.
But then on the second shoot I was told that the Panasonic Vari-Cam (which was an AJ-HDC27H, not the AJ-HDX900) always records at a rate of 59.94. But again, that is saying sampling frequency, not necessarily TC rate, correct?

That is part of my line of questioning: what are the parameters regarding timecode with Vari-Cam that define the settings for the Tascam’s LTC to follow?
Is there a constant to always follow, such as 29.97 or 30 NDF- or does the cameraman define the TC Rate (which is what I thought from the first shoot discussion)? Is there any dependence on shutter speed and sampling frequency?

Further- yes, I ingested 720p footage at 1080i. We’ve been capturing at ProRes422 1080i based on another project that mixed both 1080i HDCAM and 720p DVCPRO HD Vari-Cam. The decision was made (not mine) for sticking with 1080i and living with the slight softening in the 720p footage.
So it was our default setting for captures and I did notice halfway through digitizing the second shoot that 720p would have been ideal for digitizing… but at 3/4 through, I chose consistency in 1080i.

It’s something I’ll keep it in mind for the future and have been well deprecating myself. Still I don’t believe that would bear relevance on the time code issue… And all the above is auxiliary to my main concern of why FCP’s info for the WAVs’ Media Start is off from the TC Start listed in Wave Agent.

[Bouke Vahl]

Here we go again:

BWF does NOT carry timecode. It carries a Time Stamp, that is a number between 0 and 4147200000 (24 hours * 60 minutes * 60 seconds * 48000 Khz).
The number says how many samples have passed since midnight (read, tc 00:00:00:00) when the recording started.

So it’s up to the software to interpret the number.
Now as we all know, there is a time difference between DF and NDF.
(that’s the whole idea behind it.)

If you import a BWF in a DF project, it thus should show you a different number than in NDF.
This does not work in FCP, as you have noticed. This is not even a bug, this is just bad programming by someone who did not know what he was doing.

Open a BWF in Quicktime, enable the TC track (wrongly named of course) and you’ll see the number.
(and if you’re a geek like me, you can also find it with a HEX editor)

You could try my merge application and see if that gets it right:
https://www.videotoolshed.com/product/26/fcp-auxtc-reader
It comes with a BWF/QT merge application that puts the BWF inside a QT, based on BWF time info and QT tc info.
(also saves you a lot of manual syncing in FCP)

Now for LTC, it’s a bit old fashioned to use LTC for transcribing if you work file based. If there are no TC breaks, plain metadata (like QT TC, BWF timestamp or Sound Devices style Album/Artist information) works way easier and fool proof.)
Having said that, my Transcriber application supports all.
(and is a handy tool to check BWF timestamps in various forms, the free demo will do just fine)

https://www.videotoolshed.com/product/27/transcriber-2-dvd

To create files for Transcribing, i’ve made a small util that can do so for you. (and is FREE).
https://www.videotoolshed.com/product/59/maketranscriberfiles/2
It works the same as SoundDevices, but due to copyright it cannot make Mp3 (unless you have an option to encode Mp3 from Quicktime)
But AAC works great as well.
No guarantees that your transcription company can use the files, but that’s easy to check.

hth,

Bouke

https://www.videotoolshed.com/
smart tools for video pros