-
Read Audio Timecode 96,000khz Problem/Question
Hello,
I am using a Horita Portable Time-code generator unit with a Tascam HD-P2 audio recorder. For a setup like here on Avid Read Audio tiemcode tutorial with Media Composer.
https://www.youtube.com/watch?v=U6m1vNTeRso
I set the Horita unit to 23.98 and tried using the tascam HD-P2 timecode setting as 23.976 but the timecode generating is garbled. I then switch the tascam into 24p and both the Horita and Tascam were both synched.
I set the Audio to 96,000khz 24bit stereo on the Tascam then it was Jam synched to the Hirota. I then connected the RCA output of the Horita into the Canon 5d mk2 audio mic input. I was recording video 1080p at 24p aka 23.976, with 48,000khz audio.
I then loaded my audio and video files into Avid Media Composer 5.5.3 trial before I buy. I changed the start timecode in the bin, under duplicate to aux tc1. I then click the Canon MOV file that I imported into AVID as MXF and choose, special, read audio timecode. It reads, on the Broadcast WAV from the Tascam I imported it asks me for the time settings in Avid for the Timecode so I choose 23.98 from the drop down.
I then highlight the bin and choose autosync, I get the newley created synced clip, it has the correct video and audio, but the audio is around 6-8 secs late? Could the reason be because I had the audio recorder at 96,000khz, 24bit stereo and the audio on the Canon was 48,000khz?
It was suggested on the Avid forum on their website that “Try recording on the Tascam at 48khz rather than 96kHz. The sample rate conversion may be playing havoc with the LTC signal.”
I tested 48khz and worked fine, however any work around so I don’t have to manaully sync 50 shots? Anyway of making Avid Media Composer 5.5.3 or Pro Tools 9 to save down to 48khz or convert so the LTC works direct at 96khz in Media Composer?
Thanks,
Leo
-
1 Reply
-
I highly doubt the sample rate conversion is playing tricks on you.
My take is you get bitten by the way time is stored in BWF.
It is NOT stored as timecode, but as ‘samples after midnight’
This means that the framerate dictates the outcome of the math, thus showing you a different timecode.The audio TC however is locked to the video. I don’t think Avid is able to ‘hear’ the difference between 23.976 and 24, nor do i think it will do anything with it. It just decodes and stamps the files with what it hears.
Avid is capable of altering the BWF timestamp on import. (You get a dialoge box asking you how to interpret the speed.) But, there can be a bit of metadata in the BWF files that dictates Avid to not show that option (force ‘correct’ intepretation, in your case, force to do it wrong). Thus, this might bite you.
But to really know for sure i would need both found timecodes that ‘should’ match, and from there i can do some math on what is exactly wrong.
It is all fixable, but first to find out what goes wrong where…Bouke
https://www.videotoolshed.com/
smart tools for video pros
Reply to this Discussion! Login or Sign Up