What process is best for these multiple camera scenarios?

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kayakfishingaddict

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What process is best for these multiple camera scenarios?

PostFri Nov 15, 2019 5:20 am

I’ve had nothing but fits with DR16 when dealing with multiple cameras, please, let me explain. First, I’m a newcomer to NLEs and editing videos. However, all I want to do is throw my footage at a tool, have that tool synchronize it, and then let me cut, trim, and select angles to my hearts content to produce a video. Unfortunately, that’s easier said than done. As for why it doesn’t work inside of DR, you can read the gory details in this thread (https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=101649&p=568146#p568146)…and unfortunately, Syncaila, an excellent tool designed to overcome the synchronization shortcomings in native NLE software, also does not work due to a bug in DR; you can read the bug report in this thread (https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=102594). So that’s the bad news.

The good news, is that DR forced me to do it a different way. A way that turns out to be somewhat efficient, although I’m not yet ready to concede that it’s more efficient than the “synchronize it all” approach! In addition, I haven’t yet figured out how my second scenario below is supposed to be done…your thoughts are appreciated!

Scenario #1: Two GoPro Cameras where there is some occasional overlap where both cameras are simultaneously on.
Some quick background might help. I kayak fish and have two Hero7’s that run on batteries. Most of the time one camera is on, unless I’m trying to conserve battery life or, more likely, the battery has drained. At times, my second camera is turned on to produce a second angle, mostly when catching fish.

After my failed attempts at my desired process, here’s one that finally worked for me in this scenario…

Solution
In this scenario, I’ve found it best to use the Edit Window and follow these steps:
    1. Import media and set media metadata (angle and camera)
    2. Sort the media pool clips by TC
    3. Work down through the media to roughly select in and out points
    4. When you encounter cam1 -> cam 2 clip overlaps, create a single multicam clip (sync audio) with only those two source clips
    5. Open the multicam timeline for your new clip and append other clips if necessary/overlap (e.g. subsequent GoPro chapters)
    6. Mark your desired in and out points on the multicam clip and add it to the main timeline
    7. Switch to the multicam edit view and edit the camera angles throughout the clip
    8. Rinse and repeat (goto step 3)
At the end of this process you should now have a timeline that includes all of your desired clips, including multicam clips with angles.

Scenario #2: Two GoPro Cameras, same as scenario #1, and a Zoom h1n Audio Recorder
This is the same scenario as #1 but with high quality audio being recorded on a separate device. The desire is to replace all of the camera scratch audio with audio from the Zoom recorder. This is more difficult to do with the same solution as #1 since the start and end of the zoom audio will span the majority of video clips and those clips themselves are not contiguous.

Any suggestions on how to do this in DR 16?
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Michael_Andreas

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 6:15 am

One thing I came up with for GoPros is that you can power them from a USB battery bank via the USB connector. With a decent sized battery bank you can keep your camera recording for several hours and then the internal battery will keep it going maybe another 90 minutes or so. Memory usage is on the order of 20-25GB/hour, so a 128 GB card will cover 5 hours or so of continuous recording.

A couple of things work against this:
(1) To do this, you have to remove the connector door on the GoPro making it vulnerable to getting wet.
(2) The GoPro clock runs fast, mine range from 3 to 5 extra frames per hour. Meaning that over long periods the GoPros will drift from the sync point relative to an audio recorder and each other.
Issue (2) can be overcome by breaking it up into shorter segments. If (1) is an issue, maybe you could do something to mitigate.

I am curious as to how closely you were able to synch the clocks of the two GoPros between the two. How much fine tuning did you have to do to match the audio tracks at the first sync point?
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kayakfishingaddict

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 12:05 pm

Michael_Andreas wrote:....you can power them from a USB battery bank via the USB connector...."


Hi Michael, unfortunately that's just not an option. I submerge the camera, there's water everywhere and everything gets wet, fish splash as they get near the boat, etc. I don't believe the solution should be a physical one. The software has all it needs in the metadata and the audio waveform to synchronize everything perfectly.

Michael_Andreas wrote:I am curious as to how closely you were able to synch the clocks of the two GoPros between the two. How much fine tuning did you have to do to match the audio tracks at the first sync point?


I simply set the clocks as quickly as I can which ends up with the clocks synchronized within ~5 seconds or so. I don't use timecode to directly synchronize the clips though, I simply sort the clips by timecode in the media pool (step 2). That puts the clips in chronological order. I name the files "cam 1 - ..." and "cam 2 - ..." and when I see the initial part of the filename transition from cam 1 to cam 2, I look at the timecode columns in the media pool list and mentally compare the start and stop codes to see if there's truly overlap (step 4). All of this currently takes human inspection and observation.
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Michael_Andreas

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 12:53 pm

Yeah, I figured that wetness could be a problem with using external battery banks.

OK, re-reading more carefully you are using audio sync and the timecode is just to figure out which camera files ("chapters") overlap. At the beginning of your fishing expedition you could start the cameras recording within a few seconds and with "chapters" about 11 minutes long that would work until you have to change batteries. Hopefully no fish nearby splashing while you have the battery door open.
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Jim Simon

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 1:51 pm

I think the root of this problem is your methodology.

The best way to edit a multicamera event is to film it properly.

All cameras should be running for the entire event. Those cameras should record one file per clip, don't use cameras that break up the clip into multiple files.

Deviation from that ideal only causes problems.
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Michael_Andreas

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 1:54 pm

A GoPro is not going to meet your criteria. Indicate a camera that will meet your criteria and is usable on a fishing kayak.
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kayakfishingaddict

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 1:56 pm

Michael_Andreas wrote:Yeah, I figured that wetness could be a problem with using external battery banks


Yes, that's right.

Michael_Andreas wrote:OK, re-reading more carefully you are using audio sync and the timecode is just to figure out which camera files ("chapters") overlap.


Yes, that's right.

Michael_Andreas wrote: At the beginning of your fishing expedition you could start the cameras recording within a few seconds and with "chapters" about 11 minutes long that would work until you have to change batteries. Hopefully no fish nearby splashing while you have the battery door open.


Hmmm, first of all, I don't have that many batteries! What I try to do is run one camera while I'm fishing, and I even stop that one from recording if I'm for example moving to another spot. The second camera is to capture highlights of catching fish, etc. so I mainly turn it on only when there's some action. This process preserves batteries.

Regardless, if I were to record as you suggest. There'd still be gaps as batteries run out in 45-65 minutes or so, and thus clips from one camera wouldn't necessarily even roughly align with the other one.

So, although I'm looking at everything, including if there's some better way to capture the footage, I'm really hoping that there's a way to stitch the audio to the correct videos in post for scenario #2. At least, that would allow me to follow the same solution that I have for scenario #1. That said, please keep the ideas coming! I'm hoping that all in the community, and the program managers/software designers, will comment as to if and how DR is designed to tackle what I at least see as a typical scenario with recording live/action events from multiple cameras.
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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 2:09 pm

How are you mounting aiming your GoPros and handling a fishing pole at the same time? Using a head or chest strap?

Think a bit about some way you could run one of the cameras continuously with a battery bank. Maybe mounted in the bow aimed back at you with a plastic bag of some kind modified to act as a raincoat to protect against splashing water. That would be one less camera to handle during the action parts.
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kayakfishingaddict

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 2:15 pm

Michael_Andreas wrote:How are you mounting aiming your GoPros and handling a fishing pole at the same time? Using a head or chest strap?


Yes, I've used both.

Michael_Andreas wrote:Think a bit about some way you could run one of the cameras continuously with a battery bank. Maybe mounted in the bow aimed back at you with a plastic bag of some kind modified to act as a raincoat to protect against splashing water. That would be one less camera to handle during the action parts.


I am trying to get more creative, although I must admit I haven't thought about using a raincoat! That said, just so that I understand the premise, let me restate what I think you're saying....

If I can get a single continuously running video clip, I can then synchronize that to the continuously running audio from the Zoom h1n and replace that camera's audio. Once I've done that, I'm in the same boat as scenario #1 which already has a solution.

...is that the idea?
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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 2:24 pm

Sort of. But I don't know about how the audio syncing is going to work out, one audio file to multiple sequential GoPro files. Assuming that DR will let you do it, you could start the GoPro and audio recorder and sync the first files, and then add in the following GoPro files from that camera, and then do the audio swap

There is the issue of the fast-running GoPro clock. What you might be able to do is give a hand clap slate both at the beginning and end of the recording. If you find the GoPro running a few frames fast at the end, then maybe you could trim a frame from some of the GoPro files in the middle to keep them matched up.
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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 2:49 pm

If you go with the raincoat idea, and have trouble securing the "raincoat" to the camera, perhaps an alternative cage would work. https://www.amazon.com/Aluminum-Housing ... lla-search

Depending on your cycle times for operating the second camera and how fast you need to pick it up, you may be able to connect it to a battery bank in a protective bag and partially recharge the battery. But it might be better to just swap the internal battery for a spare fresh one if you're running low on charge.
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MrHotter

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 2:55 pm

I'm guessing that there is not very good audio markers to match by audio. I'm not sure how practical this is while fishing, but if you can add claps every time you turn on a camera, it would make it easier to match unless one camera is already underwater when you clap.

A couple things I've done to make my audio synch clips easier to work with is to make sure the metadata for each camera# and camera angle are unique.

Here are my steps:
[list=]Create a custom metadata preset that just includes camera angle and camera# (so I don't have to scroll around the metadata each time)
Select all clips from the same camera and edit the metadata to mark each angle.
Select all clips and create a multicam
check the 'detect clips from the same camera' by camera angle (this way you don't have more angles than you have recorders)
[/list]
In your case, this should make it so you have one long audio channel with two angles of video spread out across it. From there you right-click on the audio track in the multi-cam clip and select your audio recorder audio as the default and just edit video.

If the clips are not in the right place, then right-click the Multicam clip and open it up in the timeline so you can move or add the clips that did not line up correctly.

Version 16 has been the first version that actually lined up my clips fairly close, so hopefully, it will work for you as well.
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kayakfishingaddict

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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 8:15 pm

Michael_Andreas wrote:If you go with the raincoat idea, ....
Depending on your cycle times for operating the second camera and how fast you need to pick it up, you may be able to connect it to a battery bank in a protective bag and partially recharge the battery. But it might be better to just swap the internal battery for a spare fresh one if you're running low on charge.


Thanks Michael. My second camera is on a boom attached to my kayak so that I can swing it out for several angles. Sometimes I attach it to my stake out pole (a straight pole you stick into the mud under the water that is also tied to your kayak so that you can sit in one place).

I've spent a few hours today on this and I now have a solution that I'll post next.
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Re: What process is best for these multiple camera scenarios

PostFri Nov 15, 2019 9:01 pm

Ok, MrHotter....where were you when I was banging my head on this nail last week :)? I found an answer after several hours today and then I log back in and read your post which has several of the key observations that lead to the solution.

Observations that Lead to the Solution for Scenario #2
I tried everything again several times today. This time I took a look at the multicam footage in the open timeline a little closer and it turns out, DR16 will attempt to perform the desired behavior, but unfortunately it is not perfect (aka there are bugs and it doesn't get it right). So now, with my expectations reset as to how accurate DR16 would do the job, I set out on examining the clips one by one, and

    1. manually tweaking the track alignment where DR16 did select the proper clip but missed the audio synchronization by a second or two - unfortunately many of the 65 clips I worked with were misaligned;
    2. deleting a chunk of clips DR16 added to the timeline where they didn't belong....some of them were duplicated in other areas of the timeline which to me is an obvious bug in the softwarel
    3. adding in the missing clips, some of which were subsequent GoPro chapters (e.g. GH02xx.mp4, GH03xx.mp4, etc.) which were easy, and one was a far away angle that didn't have good enough audio;

You have to walk, one-by-one through each clip and ensure it was "processed" properly. It helps to keep the original clips in the media pool and not have them automatically moved to the "original... bin" folder. After you get out of the timeline, which saves it, you can move those clips to other bins.

Scenario #2 - Solution (read earlier posts for the scenario description)
In this scenario, I’ve found it best to use the Edit Window with the Media Pool open and follow these steps:
1. Import media and set media metadata (angle and camera)
2. Select all of your media and create a multicam clip
3. Open the multicam clip in a timeline and walk, one-by-one through the clips in your media pool and ensure they are (a) incorporated into the timeline - you may have to add them in yourself, (b) aligned properly, and (c) not duplicated. Fix up the errors manually.
4. Grab your multicam clip and add it to a new timeline, along with your audio if you want to simply select camera angles without messing up the audio
5. Multicam edit to your heart is content


MrHotter wrote:I'm guessing that there is not very good audio markers to match by audio. ....it would make it easier to match .... when you clap.


I agree, claps and snaps are a good practice when a new device joins in on recording the live event! This helped me line things up in the multicam timeline! To be fair, it seems the multicam aligns to the first few seconds. Unfortunately I repeated myself on a number of occasions which caused an invalid match to the first phrase instead of the repeated phrase....that's due to me turning on the second camera and speaking before it's fully on!

MrHotter wrote:A couple things I've done to make my audio synch clips easier to work with is to make sure the metadata for each camera# and camera angle are unique.


Agreed. I was already doing that but if you miss that step it's even more messed up than normal.

MrHotter wrote:From there you right-click on the audio track in the multi-cam clip and select your audio recorder audio as the default and just edit video.


I couldn't find that option. That would be helpful. As of now I unlink and then select the audio (A1) from the multicam (V1) on the program timeline and remove it. I then add the master audio as A1. I then can edit and simply select video angles.

MrHotter wrote:If the clips are not in the right place, then right-click the Multicam clip and open it up in the timeline so you can move or add the clips that did not line up correctly.

Version 16 has been the first version that actually lined up my clips fairly close, so hopefully, it will work for you as well.


That is the secret sauce. I started doing multicam after I started using DR16 a few weeks ago, so my first impression is that "synchronization" needs to improve. I'm glad to know that it's better than it has been in the past. I hope it improves even more.
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Re: What process is best for these multiple camera scenarios

PostWed Nov 20, 2019 9:15 pm

I'll add some additional details/findings now that I'm working on my second project via this process and a strong suggestion that would eliminate much of the manual work caused by the current algorithm. Does anyone from the development team read these forum posts?

Findings
    1. To be clear, when you create a multicam with a bunch of non-contiguous video clips and an audio clip that spans the entire bunch of clips, it works best to ensure that the audio clip is represented as a single file. I have found that stitching together my audio tracks from my Zoom h1n via audacity works. The h1n breaks files at the 2.5 GB mark similar to how a GoPro separates continuous footage into chapters.

    2. You must go in and add in the missing tracks. And you must delete tracks that are misplaced. I've found that short tracks get misplaced frequently, and all missing tracks are due to indistinguishable audio.

    3. It helps to have all video clips shot at the same FPS. I haven't figured out yet how much better the algorithm matches at that point, but it seems to do better. Also, all audio should be at the same sampling rate as the video, 48KHz in my case. Again, it seems to match better.

Suggestion
For the developers (btw I'm a software engineer too). I really wish that when selecting multiple clips that you first aligned by timecode and then aligned +/- 60 seconds by audio. I honestly think that would solve this entire problem. No tracks would be missing as all have time code, and short track alignment would be far more accurate as it will be in sequence. I think you could also flag/highlight the clip inside of the multitrack timeline as being aligned accurately by sound and timecode (green) or only being aligned by timecode (yellow). If you did that it would save an hour or more of prep work trying to align tracks for editing after we've sync'd them via "audio".
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Marc Wielage

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Re: What process is best for these multiple camera scenarios

PostThu Nov 21, 2019 3:51 am

kayakfishingaddict wrote:Scenario #1: Two GoPro Cameras where there is some occasional overlap where both cameras are simultaneously on.
Scenario #2: Two GoPro Cameras, same as scenario #1, and a Zoom h1n Audio Recorder

Two huge problems right out of the box: The GoPro is not a professional camera and has no ability to record timecode. And the Zoom H1 is not a professional sound recorder and has no ability to record timecode, either.

My advice would be to use a better camera for a multicam project, one that does have external (or jammable) timecode capability, and a decent sound recorder like one of the affordable Sound Devices products. A Zoom H4 plus something like a Tentacle timecode generator could work, though it's not my favorite setup.

Multicam projects are tough, but when you use reliable cameras and a great sound recorder, I can tell you the cameras are locked for the entire shoot, day-in/day-put. I've done concert projects shot over a 13-14 hour day with not even a frame of drift. But not with a $350 GoPro. If you have to use those, adjust sync by hand and get on with life. A timecode slate will at least tell you where you are, assuming it's jammed to the sound recorder. All this stuff is available economically if you rent it.

There are some major, big-time productions that use multiple GoPros for some scenes -- Grand Tour on Amazon and the Carpool Karaoke segments on James Corden's show are two I can think of -- but they work around it by having great assistant editors who work very hard at keeping everything in sync. And they do use pro audio recorders and great technicians on and off the set.
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Re: What process is best for these multiple camera scenarios

PostThu Nov 21, 2019 9:02 am

Marc Wielage wrote:
Multicam projects are tough, but when you use reliable cameras and a great sound recorder, I can tell you the cameras are locked for the entire shoot, day-in/day-put. I've done concert projects shot over a 13-14 hour day with not even a frame of drift.


If they are genlocked they won’t (*shouldnt*) drift. in the real world I do occasionally see 3 cams (F5/F55/FS7) to stay locked to sound files all day. I suspect Soundie is getting cams to jam sync regularly or using some TC lock device.

Other times cams will slip by a few frames over the day.
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kayakfishingaddict

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Re: What process is best for these multiple camera scenarios

PostThu Nov 21, 2019 9:29 am

Marc Wielage wrote:
kayakfishingaddict wrote:Scenario #1: Two GoPro Cameras where there is some occasional overlap where both cameras are simultaneously on.
Scenario #2: Two GoPro Cameras, same as scenario #1, and a Zoom h1n Audio Recorder

Two huge problems right out of the box: The GoPro is not a professional camera and has no ability to record timecode. And the Zoom H1 is not a professional sound recorder and has no ability to record timecode, either.

My advice would be to use a better camera for a multicam project, ....


Thanks Marc. I appreciate the advice. GoPro's, and the like, right now are the standard action camera for the limited, small, water prone space of a kayak and a single cameraman/fisherman that records, navigates, and attempts to catch fish all at the same time. Unless you know of something reasonable that's also waterproof to say 10'. I view the equipment maybe more as a "challenge" than a "problem", but that's just semantics.

IMHO, and ideally, DR and other NLE's that attempt to sync footage via audio, should align by time stamps/codes (roughly) and then use audio to fine tune the synchronization without the need for the professional gear. If that gets you to +/- 0.25 seconds or so, you'll get no complaints from me, nor anyone else I suspect. I'd recommend that the NLE document that error margin in the documentation and leave it at that. I'd happily jump in manually at that point. If the accuracy improves based on equipment, that's great for those with a higher budget.

Interestingly, as it stands now, synching by timecode does eliminate the "missing footage" or "unable to synch footage" issue and since I'm having to adjust the synch anyway, my next project (I tend to do one/week) I'll try to simply not do the audio synch and see if that saves me any time.
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Re: What process is best for these multiple camera scenarios

PostThu Nov 21, 2019 11:38 am

I did a quick experiment with some footage I'd recorded with several GoPros. I had several "takes" where I had stopped and restarted all the GoPros. I brought all that footage into DR, marked the camera metadata, and then generated a multicam clip based on timecode. Doing that put each camera's footage on the same track, in proper order AND synchronized within 5 seconds of each other.

A GoPro does have timecode ... of a sort. The issues are:
(1) you can't synchronize to frame accuracy with LTC (no jamming of timecode)
(2) the GoPro clock is inaccurate by around 2 to 5 frames per hour.

At some point I'll run some experiments to see how closely I can get the camera clocks up by setting the GoPro clocks right before a shoot using the GoPro app on my phone, and whether the remaining error can be taken care of on a mulit-clip basis via Clip Attributes settings.
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kayakfishingaddict

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Re: What process is best for these multiple camera scenarios

PostThu Nov 21, 2019 4:10 pm

Michael_Andreas wrote:I did a quick experiment with some footage I'd recorded with several GoPros. I had several "takes" where I had stopped and restarted all the GoPros. I brought all that footage into DR, marked the camera metadata, and then generated a multicam clip based on timecode. Doing that put each camera's footage on the same track, in proper order AND synchronized within 5 seconds of each other.

A GoPro does have timecode ... of a sort. The issues are:
(1) you can't synchronize to frame accuracy with LTC (no jamming of timecode)
(2) the GoPro clock is inaccurate by around 2 to 5 frames per hour.

At some point I'll run some experiments to see how closely I can get the camera clocks up by setting the GoPro clocks right before a shoot using the GoPro app on my phone, and whether the remaining error can be taken care of on a mulit-clip basis via Clip Attributes settings.


Thanks for your interest Michael. Did you also try to synch by audio? It would be interesting to see the results of that...assuming both cameras recorded scratch audio.
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Re: What process is best for these multiple camera scenarios

PostThu Nov 21, 2019 6:10 pm

No, I didn't try audio sync. We pretty much know that DR will not do multiple sync points.

I'd suggest that you get the GoPro app for your phone. Just before you go out on the water, use the app to sync the GoPros to network time. If "the water" is not in range to a cell phone, then do the sync before you hit the road. My thinking is that the app should be able to get the GoPros closer to the same time than fiddling around with the small touch screen on the back of the GoPro.

Still do the hand clap slate. Then you have more options.
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DR Studio 16.2.0.055, Win10Pro 1909/18363.535 - i7-6700K@4GHz, 32GB RAM
RTX 2070 8GB, "Studio" driver 442.19 2/3, prev: 441.66, 431.86
OS,Library: 1TB SSD - Project: 1TB SSD - Cache: 1TB NVMe

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