[Peter Holt]

I have one more Q if I may:

Does video have no timecode in it at all? Not even on the first frame?

Because if it doesn’t, there is little point in timecoding the audio. One needs to timecode the video also.

But I am sure I am wrong, because the HDMI-derived timecoding of audio which this does
https://tascam.com/product/dr-701d/overview/
could not work. There must be a timecode coming out of the HDMI data. Doesn’t this timecode also get recorded in the mp4 file, in the camera?

[Peter Holt]

I had an email reply from NBFX. This is getting interesting…

It turns out there is an additional config in NBFX for the GPU use, and it was not disabled in there. Actually I am very sure I did disable it there but probably an update re-enabled it.

However, I cannot disable it:

https://peter-ftp.co.uk/screenshots/2016-10-06_195837.jpg

The two lower checkboxes cannot be clicked. I have no idea what “standalone” means.

[Peter Holt]

Interesting… it must depend on what they are doing with it. It can’t possibly be bad enough for what I want : )

The DR701 also has a terrible battery life. External power (USB, or their battery pack) is really necessary for most things. OTOH the little $100 recorders can do 50-100hrs of recording on 2xAA.

I can see some people, if mono is OK, will be recording a timecode on one of the two audio channels, from a timecode generator. Then you can use any cheap sound recorder.

There is a lot of stuff online on this. One could read it for days.

[Peter Holt]

Sorry, above video is the wrong one, but I can’t edit this post. This is the right one
https://vimeo.com/178217220

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[Peter Holt]

Thanks Richard for a brilliant clarification of all this.

I just need to check out the Vegas workflow. Some google hits go back 10 years so it looks like it has been in there a long time.

Re aircraft audio, if you connect into the intercom (a.k.a. “audio panel) – this is usually done by connecting into a spare headset socket – you get the benefit of the radio squelch i.e. total silence unless somebody in the cockpit talks, or ATC talks. That is how this one
https://vimeo.com/184011280
was done. Previously I used the mike in the headset method (I bought a tiny mike and a semi-pro preamp from Sound Professionals in the USA) and that is cumbersome as it keeps falling out when you move about, and it does pick up the same aircraft noise which you hear.

I have sent this thread to Tascam and maybe they will confirm this should work… it needs to generate its own independent timecode.

I am amazed mp4 video doesn’t store the time in each frame! All the players such as VLC must be faking it, by counting frames. That is something to which I will have no solution, but then I don’t need timing to better than a second or two. However, when I have loaded video and audio from separate sources (I use the $100 Tascam mp3 recorder) onto the timeline, there is zero evident offset after a 7hr flight, so it is good enough despite the camera spending time at -25C, etc.

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[Peter Holt]

Reading some more, it looks like the key issue is that you need split-second sync between the sound recorder clock (which generates the timecode) and the camera clock.

And this is hard to achieve. One could easily achieve it over say a 10 hour project (fairly cheap quartz crystal oscillator tolerance is say 5ppm, which is c. 0.1 sec over 10 hours) but how do you sync the two to start with?

That is presumably why the DR-701 takes the video signal from the camera, extracts the time from that, and uses *that* to generate the timecode recorded onto the audio. Then nobody needs to sync anything.

But clearly this won’t work with a remotely mounted camera to which there is no access before the recording session.

The best one will be able to do is to set two two clocks as accurately as possible.

Does this make sense?

[Peter Holt]

OK, guys, many thanks… looks like I need to go up a learning curve on SMPTE ?

Vegas can use SMPTE, it seems.

Reading up on this, SMPTE involves storing time on every frame of a video and similarly storing time on every sample (?) on an audio track.

But, surely, an mpeg video file already has time embedded in every frame, surely? What does SMPTE add?

I read some web material on SMPTE in audio and it embeds the digital data in the audio, so you need a special player to strip it out, otherwise you can clearly hear it.

Searches on equipment tend to lead to this product every time: https://tascam.com/product/dr-701d/ That does just audio, with masses of features. I don’t mind the price if it actually works with Vegas Pro 13… and preferably earlier versions like MSP11 which I have on a laptop I travel with.

I also see a lot of stuff about timecode generators. Why is this a separate function, when everything containing a microprocessor has (or can have) a real time clock for about $1? (I am an electronics hardware/software designer). Presumably the DR-701D contains all that and you just feed in Line In. I have a line level audio signal connection from the aircraft intercom.

[Peter Holt]

“I don’t follow what your proposed workflow is or exactly what is a “standalone timecode recorder”?”

I would like to be able to drop an audio event onto the timeline and have it align with the video, where there is video.

“BTW: BlueTooth and WiFi both run at 2.4GHz. So I don’t understand your reluctance to use WiFI, but willingness to use BlueTooth which operates at exactly the same frequency band?”

I don’t want to use ither, but there is a huge difference in power.

“There is nothing on an aircraft, general or commercial, that operates anywhere near 2.4GHz. Except maybe the flight attendant’s MP3 player. It is guaranteed impossible that the 10s of millions of passengers ALL turned off their electronic gadgets each and every time a flight took off and landed. I appreciate extreme safety as much as the next guy, and I don’t want to crash anymore than you (or the pilot) does. But all the fru-fru about “turn off all your gadgets” things has been proved to be superstition unsupported by science.”

I don’t fly an airliner. They are well shielded, and are built to a high standard when it comes to EMC. Also there are other factors e.g. you can saturate a a circuit whose bandwidth is say only 150MHz, with a 2.4GHz signal.

[Peter Holt]

Yes; your description is spot on.

I could try it without NBFX but practically it is not easy to narrow it down, because

– a previous 80hr render worked OK (almost identical media, same FX chain)
– it takes potentially many hours of not being able to use the computer, to get one data point
– RDP etc doesn’t always corrupt it (but RDP always stops Pro 13 starting up, which is itself curious, and there may be the clue)

I have emailed NBFX asking if this is something they have heard of previously.

MSP11 and MSP12 worked fine in all respects, RDP, etc.

[Peter Holt]

Interesting… I looked at the 3000 but it uses a different waterproof housing so I would have to re-make my whole camera assembly.

Also I have no means of running a wire to the camera. It would have to run over bluetooth. I am not 100% happy about that either because you don’t want a piece of equipment, which cannot be turned off by the pilot, radiating anything, on an aircraft which might have to make an instrument landing… That is why I won’t use the wifi on the 1000V to start/stop recording.

Is there a standalone timecode recorder which would work with Vegas in the way I originally described?