[Ardour-Users] "Extract LTC from audio and align video" menu option missing from "Transcode/Import Video file" popup

Chris Caudle chris at chriscaudle.org
Wed Apr 4 19:27:39 PDT 2018

On Wed, April 4, 2018 5:00 pm, robertlazarski . wrote:
> Its a nasty signal. It might be severally clipping but I don't have meters
> on it.

I forgot you had an external interface.  Since it is USB, you could
connect it to your computer and use the meters in Ardour to check the
level of the time code signal from the F8, and adjust it until there is
plenty of headroom.
See below.

> Seems like its [i.e. phone recording] using AAC

I checked using the command line ltc tools, and I can create a wav file,
convert to AAC using the old Nero encoder, decode using the Nero decoder,
and the ltcdump output is identical between the original wav file and the
wav->aac->wav path.
However, the original wav file creates the LTC with a max level of -18dB
FS, and the encoded/decoded version of the same has a max level of -15 dB
FS.  I don't know if that is called out in the AAC spec anywhere or if
that is peculiar to the Nero AAC encoder/decoder pair, but very curious. 
Be sure to leave plenty of headroom in the original in case that is some
kind of common behavior in the AAC encoder or encoder/decoder pair.

You can see the max level with sndfile-info if you leave out the "-b"
argument, it will print  information about the audio data instead of the
BWF metadata.

Chris Caudle

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