Old 04-04-2021, 02:19 PM   #1
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Default Align audio with recorded start time

I've already tried BWF preferred source position script - this is aligning audio to where it was recorded in the project. Useful, but not what I need.

I have 3 segments of recorded audio with 3 overdubs done. If I use BWF preferred it puts the overdubs over top of each other. What I would rather have is for the the item to be lined up in time relative to the first item, or to project start time. Whatever, really - so long as they're time accurate. I'd like to line them up to camera footage that was running continuously the whole time to save the video editor from aligning everything themselves.

Anyone got a script or method for this? I tried to do it manually even but there is not enough resolution given by BWF OriginationTime in Source Properties to be accurate with it to the millisecond.
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Old 06-02-2021, 06:19 PM   #2
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Old 06-02-2021, 11:40 PM   #3
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Well, TimeReference is in samples (since midnight)...

Which "BWF preferred source position script" are you using?
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Old 06-06-2021, 09:31 AM   #4
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Well, TimeReference is in samples (since midnight)...

Which "BWF preferred source position script" are you using?
"Item: Move to media source preferred position (BWF start offset)"

Not a script, my bad.

So I need to make my own script for TimeReference then eh
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Old 06-06-2021, 10:07 AM   #5
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Might be worth looking at
Script: amagalma_Nudge to source preferred position (used by BWF) for selected items' active takes.lua

Although, there's a magic number (4294967295) in there which looks a bit off to me...
shouldn't it be 0x100000000 ? But I guess it doesn't matter, really... unless your sample rate is high
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Old 06-07-2021, 10:12 AM   #6
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That script although I see timeref mentioned all over in it, is still aligning to project recording placement, not real time.

I also tried a script by Rodilab but it appears to be broken.

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Old 06-07-2021, 11:09 AM   #7
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I've never used the script, so can't comment directly.

I suspect the issue might be that the "first sample count since midnight" is relative to timeline midnight, i.e. 00:00 on the timeline and not to realtime midnight... At least, this is how it appears to work in Reaper.

Unlike OriginationTime which is realtime - or at least it would be if it were either in UTC, or included an indication of timezone. But it's only got second resolution...

tbh I'm not sure what you're trying to do - if you're aligning overdubs with a video, surely project time (or relative to 00:00 on the timeline) is what you want?

Obv, there'll be some kind of offset from video timecode (?) to your project time. Would you want to set your project time so that it matches video? Maybe I'm not understanding you. (Quite possible)
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Old 06-07-2021, 12:13 PM   #8
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tbh I'm not sure what you're trying to do - if you're aligning overdubs with a video, surely project time (or relative to 00:00 on the timeline) is what you want?
Project time didn't work because each time I made a new recording of overdub (playing back the original recording to the players) the BWF time was set to the same start point for each overdub. However, the video is one continuous file capturing the entire session.

I wanted to align the overdubs to their actual recorded time relative to.. anything. The important part being the exact samples between each take's recording start, so that when the videographer aligns the session the overdubs will line up with his camera footage, too.

Alignment to "midnight"/project time 0 is not a problem, but the scripts I tried either weren't doing that or were moving files to inaccurate locations (I did a test).
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Old 06-07-2021, 01:15 PM   #9
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Ahh, OK, you've got a video of the recording process? And a bunch of (audio) files that were recorded - into an audio only project while the camera was running? Have I got that right? I'm a bit slow.

I guess you'd have needed to record timecode (from the camera / external generator) alongside your overdubs to make them easier to line up with the video. Bit late now, sorry, but that's what I'd have done.
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Old 06-08-2021, 08:38 AM   #10
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Originally Posted by jrk View Post
Ahh, OK, you've got a video of the recording process? And a bunch of (audio) files that were recorded - into an audio only project while the camera was running? Have I got that right? I'm a bit slow.

I guess you'd have needed to record timecode (from the camera / external generator) alongside your overdubs to make them easier to line up with the video. Bit late now, sorry, but that's what I'd have done.
Camera files aren't needed, we have alignment clap at the start and it doesn't need to be sample accurate. What I need is the audio to be aligned to itself, therefor matching the camera's recorded time.
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Old 06-08-2021, 11:14 AM   #11
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OK, then you've lost me again. I think you'd need to draw me a picture.

"3 segments of recorded audio with 3 overdubs done"

What's a "segment" here?

Does this mean you added (overdubbed) /recorded new items/takes to a project in 3 separate places?

"audio to be aligned to itself" what? How can audio not be aligned to itself?

Surely you want the (overdubbed) audio to be aligned to the video? If you're video-recording someone recording into a project, including stops & starts etc, then those "overdubs" will be aligned to each other in project time - but I got the impression that you wanted them to line up with the video time
Quote:
I'd like to line them up to camera footage that was running continuously the whole time to save the video editor from aligning everything themselves
The "whole time" you were doing what? Your usual recording practice? Record a bit, stop, go back / forward, record a bit more?

The only way I can think of doing that easily would be for the overdubs to be multichannel items including LTC from the camera (or from a generator that the camera also records)
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Old 06-09-2021, 12:03 PM   #12
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Ok this picture explains everything.

The 3 takes are all recorded into the same spot. Yet the video rolled on, so their relation to the original recording synced up to the video needs to be changed. By how much time? That's where I'd like to use a script to see how much time (since midnight) in both the first file and the overdubs, as the difference in samples would give me how many samples I need to offset the files from where they are in the project.

The track below with the takes split up shows where they 'should be'.

There's also another randomly placed audio where a new recording was started (lets say for recording something we forgot, like a bit of speech, to later insert).
It is recorded at marker 1, but in the video file should start at marker 2. Again, if I knew exactly how many samples offset from the first audio file, I could place this perfectly in alignment with the video file without even having the video file (which I don't). This is what I mean by the audio being aligned with itself.

Quote:
The only way I can think of doing that easily would be for the overdubs to be multichannel items including LTC from the camera (or from a generator that the camera also records)
A WAV with BWF data that has some sort of reference to real life time, seconds since 1970 or something, should let me line it up without any camera data. This is what I'm looking for. I was certain this data is recorded.

By the way, the video editor just used his software to auto-align the audio which it matched to similar audio it found in the camera's audio. Like magic, a couple clicks. But I still would love to know how to deliver completely time accurate audio when overdubs are needed.


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Old 06-09-2021, 12:20 PM   #13
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I've been following this but I haven't replied because I don't know the answer. I'm pretty sure this is what I've run into when I wanted to "film" a recording process, including overdubs but I need the overdub attempts in reapers audio to align with the overdub attempts in the video which will obviously be further down the linear video timeline.

I don't think PluralEyes could solve this either but you might check just to confirm. What I've usually done, is that if the audio isn't overly compressed, it's pretty easy to see the waveform patterns at a resolution that is sub-frame accurate (I always record the live audio as it happens to the video track for such reasons) - then I slide the overdubs (in order) and match the audio item waveform to the next one that matches in the video's audio waveform. It's a caveman approach and will be a PIA very quickly for something more complex but something shorter and simpler is probably doable.
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Old 06-09-2021, 12:24 PM   #14
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Pluraleyes is basically what the video guy did except it's a feature built into Adobe Premier

From BBC user guide for BWF Wav, TimeReference:

"These fields shall contain the time-code of the sequence. It is a 64-bit value which contains the first sample count since midnight. The number of samples per second depends on the sample frequency which is defined in the field <nSamplesPerSec> from the <format chunk>."

This does sound like what I need. I'll have a look at making my own basic script perhaps. The one by Rodilab seemed so promising, maybe there's an error in it.

Edit:

It does not do what I thought it does. It says what the sample was since the start of the DAW. If you record at 0 it consistently says 0. Oh well.

OriginationTime is the closest we can get. It turns out milliseconds are recorded, but Reaper isn't displaying them in source properties.

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Old 06-09-2021, 12:30 PM   #15
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Quote:
Originally Posted by Fergler View Post
Pluraleyes is basically what the video guy did except it's a feature built into Adobe Premier
Yea, Davinci added a decent alignment tool not long ago but I'm not sure it can handle the overdub thing.
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Old 06-09-2021, 02:20 PM   #16
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Quote:
Originally Posted by Fergler View Post
A WAV with BWF data that has some sort of reference to real life time, seconds since 1970 or something, should let me line it up without any camera data. This is what I'm looking for. I was certain this data is recorded.
Yes, that would be lovely. Problem is - BWF:OriginationTime has only second resolution
"8 ASCII characters containing the time of creation of the audio sequence.
The format shall be « ‘hour’-‘minute’-‘second’» with 2 characters per
item."


And BWF:TimeReference is "the time-code of the sequence. It is a 64-bit
value which contains the first sample count since midnight."


(and that's not midnight on the day of origination - that's timecode midnight i.e. an arbitrary 00:00:00

There is no real-time reference with the resolution you require. At least none that I can see.

This is the reference:
https://tech.ebu.ch/docs/tech/tech3285.pdf


If you figure out a way of doing it - I'm happy to be corrected - but the only way I can think of is to record (video) timecode alongside your overdub. Otherwise I don't see how reaper gets to know about video time?
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Old 06-11-2021, 03:28 PM   #17
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Quote:
Originally Posted by jrk View Post
. . .

And BWF:TimeReference is "the time-code of the sequence. It is a 64-bit
value which contains the first sample count since midnight."


(and that's not midnight on the day of origination - that's timecode midnight i.e. an arbitrary 00:00:00

. . .

^^This…

I’ve had a multitrack recorder chasing video LTC to give me a different TC BWF copy of recorded audio.

Edit: won’t help you here, but you can record LTC as audio from a TC generator converting real time.

>
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