Welcome, Guest
Username: Password: Remember me

TOPIC: Wav/BWav Question

Wav/BWav Question 11 Feb 2018 13:48 #94085

  • Andreas Kiel
  • Andreas Kiel's Avatar
  • OFFLINE
  • Platinum Boarder
  • Posts: 917
  • Thank you received: 154
  • Karma: 30
I haven't worked with those files directly inside FCPX for a while - or better said: never.
For good reasons I didn't touch them since FCP 5 or so.
One of the reasons had been TC. When Apple told me that they finally have integrated BWF reading they implemented a stupid error when reading BWav TC. I told them, they agreed but never fixed.
Now I got a user question and have to care about this again after more than a decade.
Example:
File header shows a time of "samplesSinceMidnightLow" of 4.090608E+9 at 48kHz
Simple math results in a time of 23:40:21.000 whereas FCPx says: 23:38:55.833333333.
Other apps follow the "simple math" as well.
fcpxml doesn't have a "virtual tc" like xmeml had. It also doesn't accept the TC overwrite from iXML.
So what to do?
Regarding iXML and "Assign iXML track names if available":
When a stereo track has a name for each track FCPx only assign one.
Does all the tracks need to be mono?

ixml.png
The administrator has disabled public write access.

Wav/BWav Question 11 Feb 2018 19:23 #94086

  • Andreas Kiel
  • Andreas Kiel's Avatar
  • OFFLINE
  • Platinum Boarder
  • Posts: 917
  • Thank you received: 154
  • Karma: 30
Partially answering my own question:
The example file mentioned did have an iXML. This included a SPEED: 24 and a TIMECODE_FLAG: DF which results in frame rate of 23.976
The above mentioned time of 23:40:21.000 equals 85221 seconds - latter are displayed correctly in FCPx.
Now with a given video rate FCPx will convert the audio into "video frames" and the time (timecode) is converted to 23:38:55:20.
This means going from absolute time based to relative frame based.
Whether this is right or wrong can be discussed - in any case it is problematic.
Having several audio sources with time stamps will not sync or run out of sync in case they have an iXML or not.
The administrator has disabled public write access.