<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Apr 4, 2018 at 8:27 PM, Chris Caudle <span dir="ltr"><<a href="mailto:chris@chriscaudle.org" target="_blank">chris@chriscaudle.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span class="gmail-m_5220533512776865169gmail-">On Wed, April 4, 2018 5:00 pm, robertlazarski . wrote:<br>
> Its a nasty signal. It might be severally clipping but I don't have meters<br>
> on it.<br>
<br>
</span>I forgot you had an external interface. Since it is USB, you could<br>
connect it to your computer and use the meters in Ardour to check the<br>
level of the time code signal from the F8, and adjust it until there is<br>
plenty of headroom.<br></blockquote><div><br></div><div>I might try that if I am still stuck much longer. Its a good idea. <br> <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
See below.<br>
<br>
> Seems like its [i.e. phone recording] using AAC<br>
<br>
I checked using the command line ltc tools, and I can create a wav file,<br>
convert to AAC using the old Nero encoder, decode using the Nero decoder,<br>
and the ltcdump output is identical between the original wav file and the<br>
wav->aac->wav path.<br>
However, the original wav file creates the LTC with a max level of -18dB<br>
FS, and the encoded/decoded version of the same has a max level of -15 dB<br>
FS. I don't know if that is called out in the AAC spec anywhere or if<br>
that is peculiar to the Nero AAC encoder/decoder pair, but very curious.<br>
Be sure to leave plenty of headroom in the original in case that is some<br>
kind of common behavior in the AAC encoder or encoder/decoder pair.<br>
<br>
You can see the max level with sndfile-info if you leave out the "-b"<br>
argument, it will print information about the audio data instead of the<br>
BWF metadata.<br>
<span class="gmail-m_5220533512776865169gmail-HOEnZb"><font color="#888888"><br>
--<br>
Chris Caudle<br>
<br>
<br>
</font></span></blockquote></div><br></div><div class="gmail_extra">On the files I just created today I see:<br><br>[linux-7cab(iksrazal)] <br> /home/iksrazal> sndfile-info output_audio.wav | grep -i db<br>Signal Max : 32768 (0.00 dB)<br><br>And if I learned how this works right, 3212 samples is 3212/48000 = 66ms. That's not my problem if I understand correctly. <br><br>[linux-7cab(iksrazal)] <br> /home/iksrazal> ltcdump output_audio.wav | head<br>Note: This is not a mono audio file - using channel 1<br>#User bits Timecode | Pos. (samples)<br>#DISCONTINUITY<br>00000000 06:05:34.24 | 3212 4683 <br>#DISCONTINUITY<br></div><div class="gmail_extra">00000000 06:05:34.25 | 4684 61nc 54 <br></div><div class="gmail_extra">00000000 06:05:34.26 | 6155 7626 <br>00000000 06:05:34.27 | 7627 9097 <br>00000000 06:05:34.28 | 9098 10571 <br>00000000 06:05:34.29 | 10572 12040<br><br></div><div class="gmail_extra">I posted my files to see if that helps understand my sync problem. At this point my theory is the amount of sync delay I see, is pretty much exactly the delay between pressing start on the F8 and then a few seconds later pressing start on the phone video. I am seeing around a 6 second delay in this example. <br><br></div><div class="gmail_extra">In the video, I am using a chase light step sequencer to trigger the drum beat, which probably is more useful than the brief piano chords i tried to make apparent by my arm movements. I start the video filming my other phone with a wall clock running, to help show what's going on. The F8 internal clock does not sync to NTP or GPS best I can tell so I eye balled the F8 date setting the best I could. <br><br></div><div class="gmail_extra">Also, I could be doing something wrong in Ardour. All I am doing is Session --> import (F8 wav) . then Session --> open video. <br></div><div class="gmail_extra"><br></div>MP4 phone video with LTC, since this is a public link I advise extreme caution opening any file with LTC.<br><br><a href="https://drive.google.com/open?id=1IMiWJt936rqvVjKj8uAtGRfheC8JNW01">https://drive.google.com/open?id=1IMiWJt936rqvVjKj8uAtGRfheC8JNW01</a><br><br>F8 BWF wav with 4 tracks. The piano seems a little low compared to the drum machine, will try to fix that next time. <br><br><a href="https://drive.google.com/open?id=1XbTi_sKNM-XVTyPrIicMQXIeKgjRTD26">https://drive.google.com/open?id=1XbTi_sKNM-XVTyPrIicMQXIeKgjRTD26</a><br><br>Thanks!<br>Robert<br><div class="gmail_extra"><b><br><br></b></div></div>