<div dir="ltr"><br><div><div class="gmail_quote"><br><div class="gmail_quote">On Mon, Apr 2, 2018 at 3:24 PM, Robin Gareus <span dir="ltr"><<a href="mailto:robin@gareus.org" target="_blank">robin@gareus.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">Hi again,<br>
<br>
On 04/02/2018 09:52 PM, robertlazarski . wrote:<br>
[...]<br>
<span class="gmail-"><br>
> However, the video and audio are out of sync. If I press the F8 record<br>
> button before I start the video, the audio comes in early. If I press the<br>
> F8 record button after I start the video, the audio comes in late.<br>
<br>
</span>That sounds like both recorders are free-running.<br></blockquote><div><br></div><div>Might be, I tried using time of day timestamps and it didn't help. <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
Are you using a common timecode generator that syncs the two devices?<br>
<br>
Where does the LTC that's recorded on the camera come from?<br>
What timecode does the audio-recorder use to set BWF information?<br></blockquote><div><br></div><div>All timecode comes from one source: The F8. More details below. <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
> [..]<br>
<span class="gmail-">> I spent some more time reading the docs. In Xjadeo I couldn't get the<br>
> offset "+" and "-" buttons to work.<br>
<br>
</span>When Ardour launches xjadeo, most of the direct interaction with Jadeo<br>
is disabled. It becomes a dumb display under Ardour's control.<br>
<br>
You can drag/drop the video in Arodur's video-timeline to align it,<br>
xjadeo will follow, but that should not be needed.<br>
<br>
If the timecode on the video (LTC) matches the timecode of the audio<br>
(BWF), everything will just line up all by itself.<br>
<br>
Note that both audio and video may import at some late position in the<br>
timeline. e.g. at 14:00:00:00 and may not be visible with default<br>
zoom-level.<br>
<br></blockquote><div><br></div><div>I tried zooming in and out and didn't see an obvious misalignment. <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
> [..]<br>
<span class="gmail-">> the "space" bar starts and stops as expected.<br>
<br>
</span>Yes, those keys are forwarded to Ardour.<br>
<br>
[..]<br>
<span class="gmail-">> I tried exporting from Ardour to video and it took about 9 hours - however<br>
> it generated an export.avi with just audio - no video and "seek" seems to<br>
> not work in mplayer.<br>
<br>
</span>Wow. What range did you export? a 12+ hour video?<br>
<br></blockquote><div><br></div><div>I need to watch out for blank video space in the imports, I didn't expect it. <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">
[..]<br>
<span class="gmail-"><br>
> I don't understand yet, how to match the timestamps I see from ltcdump on<br>
> the MP4 converted to WAV, and what I see from bwftool on the F8 generated<br>
> WAV. I am still learning.<br>
<br>
</span>Ardour should do that for you, but if you do want to do this manually:<br>
<br>
<br>
I don't know bwftool, `sndfile-info --broadcast` prints the raw data:<br>
audio-samples since midnight.<br>
<br>
e.g. if you started recording audio at 8am sharp at 48kHz. it'll print<br>
show <a href="tel:4147200000" value="+554147200000">4147200000</a> ( 8 hours * 3600 seconds/hour * 48000 samples/second)<br>
You can do the reverse and find the time when given audio-file was<br>
recorded. the <a href="tel:4147200000" value="+554147200000">4147200000</a> would translate to 08:00:00:00<br>
<br>
As for video, use ltcdump and take the first found timecode.<br>
<br>
Timecode | Pos. (samples)<br>
07:58:00:00 | 0 1919<br>
07:58:00:01 | 1920 3839<br>
07:58:00:02 | 3840 5759<br>
<br>
above means at audio-sample "0" (beginning of the video) it's<br>
07:58:00:00. In this example the video-recording was started 2 mins<br>
before audio (08:00:00:00).<br>
<br>
<br>
Cheers!<br>
<div class="gmail-HOEnZb"><div class="gmail-h5">robin<br>
<br><br></div></div></blockquote><div> </div></div></div><div class="gmail_extra"><div class="gmail_quote">On my latest files I am attempting to use "time of day" timestamps in the timecode, using the F8 "Int RTC" mode. <br><br></div><div class="gmail_quote">The
sync error pattern I am noticing, is the first entries of LTC in the
MP4 file seem to be missing or corrupted. The POS from ltcdump never starts at zero. When I open the raw MP4 I see
no such obvious problem. <br><br></div><div class="gmail_quote">In a
nutshell, there is a 12 second delay of audio in the video I see in
Xjadeo, that seems to correspond with the 12 seconds missing in the LTC
on the video. <br><br>I am seeing the same pattern on every file. Hopefully the shell output makes sense. I see this
"DISCONTINUITY" message in every file I create, could that be my problem?<br><br></div><div class="gmail_quote">One other thing I notice, is the timecode in the Ardour UI starts at zero, not time of day. <br></div><br>[linux-7cab(iksrazal)] <br> /home/iksrazal> sndfile-info -b F8.wav <br><br>Version : libsndfile-1.0.25-exp<br><br>Description : SPEED=29.970D<br>TAKE=004<br>UBITS=00000000<br>SCENE=180403<br>TAPE=180403<br>CIRCLED=FALSE<br>TR1=Tr1<br>TR2=Tr2<br>TR7=Tr7<br>TR8=Tr8<br>NOTE=EVE<br><br>Originator : ZOOM F8<br>Origination ref : <br>Origination date : 2018-04-03<br>Origination time : 18:31:09<br>Time ref : 0x0bebdd5f1 (66669.002354 seconds)<br>BWF version : 1<br>UMID : <br>Coding
history : A=PCM,F=48000,W=24,M=multi,T=F8;VERSION=1.10;1:1 0 0 R 1
00;2:1 0 0 CNTR 00;3:0 0 0 CNTR 00;4:0 0 0 CNTR 00;5:0 0 0 CNTR
00;6:0 0 0 CNTR 00;7:1 0 0 CNTR 00;8:1 0 0 CNTR 00;L:0 1 0 CNTR
00;R:0 1 0 CNTR 00;<br><br><br>[linux-7cab(iksrazal)] <br> /home/iksrazal> ltcdump phone_video_with_ltc.wav | head<br>Note: This is not a mono audio file - using channel 1<br>#User bits Timecode | Pos. (samples)<br>#DISCONTINUITY<br>00000000 18:31:21.29 | 2639 4239 <br>#DISCONTINUITY<br>00000000 18:31:22.00 | 4240 5841 <br>00000000 18:31:22.01 | 5842 7442 <br>00000000 18:31:22.02 | 7443 9044 <br>00000000 18:31:22.03 | 9045 10646 <br>00000000 18:31:22.04 | 10647 12247 <br>00000000 18:31:22.05 | 12248 13849</div></div></div>