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Bouke

new app to add / change timestamp on el cheapo recorders

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Hi guys,
A soundguy doing sports with lots of small recorders asked me to promote files from small, non-tc capable recorders to BWF.
So, I've made him something that does this, and also can include a custom offset.
So, you can set the actual TC 'somewhere' in one of the files (it has a player build in), and all the files will get the 'correct' timestamp based on a bit of math on their file creation time.

(Of course this is only second accurate for the other files, as the creation time is not more accurate than that.)

Now my questions:

-What more should I add to make it practical for daily use? (metadata / sound report or is this overkill?)
-Since there is a bug in 'some' versions of OSX that replaces the file creation time, do you guys have a SOP for offloading cards? Or should I add it?

-Should I add compensation for drifting clocks? I know for sure that internal clocks will drift, but I don't know if this is a fairly stable drift. If the latter, it's easy to calculate that and compensate for it. That could make it a bit more accurate.

-Do the cards in these recorders have 'some' form of ID what recorder it was that used them? (I can imagine that being practical to identify the files later on.)

 

Other ideas?

 

If you want to toy with it as it is now (fully functional but not all bells and whistles that are possible), drop me a line.

 

Bouke

 

 

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Hi Bouke,

This is quite timely for me as I have a show going out in 3 months that'll be deploying a large quantity of Zoom H3-VR ambisonics recorders (among other things). These do actually write timestamped BWAVs, though the timestamping is from their domestic-quality RTC so not really production / post friendly. Plan A is to pair each one with a Timecode Systems Blue, which Zoom is allegedly going to support in a 'future firmware update' that may or may not happen in time.

 

I'm guessing with your new app, we could go around each recorder with a TC Slate (or even better, Movieslate app, that can create a clap time log) and give each Zoom a clap shortly after pressing record on each one, then the data wranglers can go in after upload with your app, find the clap,  and enter the matching real production TOD TC from that log? That sounds as accurate and labour-efficient as any other plan I have. It may actually be more robust than the TCS Blue idea. I'm guessing it will work fine with 4-channel Poly BWFs as input?

 

Now to your questions...

 

- Sound report: not a big deal for me, as I'd be handling that along with the other recorders another way. Ability to add Metadata (specifically track names that would show up in Pro Tools as channel names) might be useful. In the case of the H3-VR, it will split files when they exceed 4GB, supposedly without dropping samples, so it might be useful to be able to tell the App to stamp consecutive files with the next TC frame from the calculated end of the last file rather than the next full second when you know this is the case.

 

- We'd be using Hedge to upload, which deals with maintaining timestamps, but for all these cards, if your App had a built-in uploader that would be more efficient. What I'd not want is for the app to be modifying the original file on the micro-SD card in any way, we'd always be running it on an uploaded copy to make the delivery file.

 

- Timecode drift will of course happen due to slight differences in the clock rate between the recorders and cameras, and is usually a steady drift unless the cheap device is experiencing large temperature variations. The only way to compensate for this is to run a non-pitch-shifting time compression/expansion DSP process. You would of course need access to the 'reference' clock or file to know the amount of correction to apply. There is now a quite effective DAW plug-in for this (Auto Align Post) assuming you have matching reference audio from a camera or TC recorder. This can even deal with a fluctuating drift as it's really meant for aligning a Lav and a Boom track where the talent is moving in relation to the boom.

 

- Recorder IDs.. Im pretty sure most of the current handy recorders that natively create BWFs will stamp a device name (shows up as 'Originator' in WaveAgent), but I suspect if you have more than one of the same model, they'd appear the same. All the Zoom recorders can have a custom filename with user-defined text followed by a sequential 'take' number we use to tell them apart.

 

I'd certainly like to have a look at what you have already.

 

Cheers, nick

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My votes:  Report: yes.   Drift comp: I don't see how you can calc this, since the drift is partly caused by environmental factors in recorders without TXCOs.  Recorder ID: yes.  I would consider using the app for downloading instead of "finder copy/drag+drop".  Metadata editing: yes, for sure.  TC starts, scene+take+notes entry.

 

thanks!

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Ok.
For the drift, what I would need is a (manual) correct TC for one file, and another (manual) correct for a later file. The further apart the better. (At least an hour, more is better.)

This way I can do the math if the clock is slow or fast, and compensate based on that. But it will not compensate for temperature drifts, it will be just a bit of an improvement. (My old mac clock was 4 seconds slow over 24 hours, that is a lot...)

 

Now, if the files are already BWF, they are stamped as a accurate as the clock in the device is I presume.

You can use that as well to set the correct timestamp, and the math on other files can be done on the offset of the BWF timestamps rather than the creation time.

If a file is split due to the 2 (or 4) gig limit, it won't be a problem since all get the same offset and all should be well.

 

@nick, you can also walk around with your master TC device, insert that and record a few seconds or so on the cheap device, switch back to mics and  then have my LTCreader to 'work on wave', and let it rip away. It can do the same thing, reading the LTC and setting the guessed values on all other files from that folder.

 

For offloading and metadata, i'll build it in tomorrow and send you test versions.

 

 

 

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Bouke wrote: @nick, you can also walk around with your master TC device, insert that and record a few seconds or so on the cheap device, switch back to mics and  then have my LTCreader to 'work on wave', and let it rip away. It can do the same thing, reading the LTC and setting the guessed values on all other files from that folder.

 

I thought of that, but unfortunately the Zoom H3-VRs don't have an external input - only the onboard ambisonic mic array. I actually tried feeding TC into a small speaker and holding it close to the mics, but neither your LTC Reader (demo) nor the Tentacle software could decode it.

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33 minutes ago, nickreich said:

Bouke wrote: @nick, you can also walk around with your master TC device, insert that and record a few seconds or so on the cheap device, switch back to mics and  then have my LTCreader to 'work on wave', and let it rip away. It can do the same thing, reading the LTC and setting the guessed values on all other files from that folder.

 

I thought of that, but unfortunately the Zoom H3-VRs don't have an external input - only the onboard ambisonic mic array. I actually tried feeding TC into a small speaker and holding it close to the mics, but neither your LTC Reader (demo) nor the Tentacle software could decode it.

That was a GREAT "Hail Mary", though!

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I rarely work with such recorders, but when I do I really really don’t like entering any form of Metadata on the recorder, so for me it would be a cool option if your program could 

 

- let me enter the channel names of one track and then it will automatically do that on the other tracks (as an option)

 

- allow me to either rename one file and then automatically renames all other tracks the same but adding a suffix or alternatively add a custom pre- or suffix to every takename. 

 

Since most will use these recorders in a „press record once and let it roll all day“ scenario (or so I assume), these would be luxury feature and are non-essential

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Hi Constantin,
Please elaborate on the file names.

Metadata can hold a name as well, not sure who uses that.
(I personally hate it when a filename in my bin does not match the filename on disk on most scenarios)

 

 

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On 1/23/2019 at 2:38 PM, Bouke said:

Hi Constantin,
Please elaborate on the file names.

Metadata can hold a name as well, not sure who uses that.
(I personally hate it when a filename in my bin does not match the filename on disk on most scenarios)

 

 

 

Hi Bouke, what I meant was that I could edit the filename itself. Not necessarily in the metadata. Although there could be an option (like on SD's WaveAgent) to rename the file following the name field in the metadata. Recorders will often name files according to their own convention, like 33528-20192401_001. The 001 part being the takename. It'd be useful if I could rename the first file as for example: Sc23-car_001. The program would rename all following files like that, but keep the take counter. 

(thanks for the trial, I hope I'll find some time in the next few days to try it out).

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Ok, the app is public now.

You can find it here

It does all that is promised, and a bit more.

Aimed at you having to do as little work as possible, but I can imagine it will be a HUGE timesaver in post.

 

Now, I've done my best (to my horror I now see i've been working a month on it.) to accommodate all needs, but I'm an editor and coder, not a sound guy.
So, there probably are more improvements to make. Don't by shy with comments!

 

Oh, fair warning:

If you run the demo:
Offloading will do no harm to your files.
Altering the metadata / setting timestamps WILL! (It will add 2 seconds of silence every 25 seconds.)

 

Screen Shot 2019-02-17 at 15.42.14.png

Screen Shot 2019-02-17 at 15.40.14.png

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