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Gear / Technical Help => Photo / Video Recording => Topic started by: juliocruz on January 03, 2021, 07:11:23 PM

Title: Synch 3 video parts with 1 separate audio track: free software
Post by: juliocruz on January 03, 2021, 07:11:23 PM
I record concerts with a camera, but you can only record up to 30 minutes continuously. I also have to switch batteries after about 1 hour, so after a concert I normally end up with 3 video parts. I record audio separately, so I have 1 separate audio track. Is there free video editing software with which it is easy to synch the 3 video parts with the 1 separate audio track? I would like to leave the separate audio as it is, so prefer that the screen goes black between the video clips. I read a bout Davinci Resolve, but don't know if this software could synch my 3 video parts with my 1 separate audio track. Hopefully someone can help. Thanks in advance!
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: beatkilla on January 03, 2021, 08:01:50 PM
I don't know about free?

I use Sony Vegas Pro.

I can synch them for you if you'd like just let me know.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: beatkilla on January 03, 2021, 08:04:46 PM
https://www.vegascreativesoftware.com/ca/free-trials/video-editor-free-download/


Here is the 30 day free trial versions
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: taper420 on January 03, 2021, 08:43:26 PM
The only standalone program I know is Plural Eyes and that's not free.

Problem is, on long clips like this you're gonna run into drift regardless of if you get the start points in sync. The clock of the camera needs to be slave or master to the clock of the audio recorder. Since I doubt your camera has a genlock input, that means the camera has to be master and the audio recorder needs to slave in some way. The simplest modern solution for you (assuming you have a DSLR due to the 30 minute limit) I think would be HDMI into something like the Tascam DR-701D or Sound Devices Mixpre 10 II. LTC, word clock, or spdif are options for sync that probably wouldn't work with your setup (at least without other converters/time sync boxes). Otherwise you're looking at correcting drift every few minutes or having to mess around with a time stretch/compress operation. Which is probably what you're gonna have to do with the clips you're currently trying to work on.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: juliocruz on January 04, 2021, 07:16:41 AM
Thanks for the replies, guys! Does anybody have experience with Davinci Resolve?
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: sabre on January 05, 2021, 03:58:54 AM
Davinci Resolve can join your multiple videos together and you can also sync an external audio recording to it as well.

Just check YouTube for some tutorials

Join clips
https://www.youtube.com/results?search_query=davinci+resolve+join+two+clips

Sync separate audio track
https://www.youtube.com/results?search_query=davinci+resolve+sync+audio+and+video
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: guitard on January 09, 2021, 10:51:42 AM
I record concerts with a camera, but you can only record up to 30 minutes continuously. I also have to switch batteries after about 1 hour, so after a concert I normally end up with 3 video parts. I record audio separately, so I have 1 separate audio track. Is there free video editing software with which it is easy to synch the 3 video parts with the 1 separate audio track? I would like to leave the separate audio as it is, so prefer that the screen goes black between the video clips. I read a bout Davinci Resolve, but don't know if this software could synch my 3 video parts with my 1 separate audio track. Hopefully someone can help. Thanks in advance!

I always manipulate the audio to sync to the video.  For the missing parts between clips -- you can use snippets of video from elsewhere during the show or a series of still shots.  Sometimes I take a clip of one of the musicians doing something like head banging and create a slo-mo version and overlay that over the black screen.  There are a few other 'tricks' you can use to cover up the blank spots.  I like doing that so there is something there for people to watch during those parts.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: voltronic on January 09, 2021, 03:18:12 PM
Davinci Resolve can join your multiple videos together and you can also sync an external audio recording to it as well.

Just check YouTube for some tutorials

Join clips
https://www.youtube.com/results?search_query=davinci+resolve+join+two+clips

Sync separate audio track
https://www.youtube.com/results?search_query=davinci+resolve+sync+audio+and+video

I use Resolve. It is a full-out professional video NLE for free. The Elastic Wave function in the Fairlight Audio module also works quite well if you need to do some time-stretching.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: jerryfreak on January 09, 2021, 06:20:06 PM
I always manipulate the audio to sync to the video.  For the missing parts between clips -- you can use snippets of video from elsewhere during the show or a series of still shots.  Sometimes I take a clip of one of the musicians doing something like head banging and create a slo-mo version and overlay that over the black screen.  There are a few other 'tricks' you can use to cover up the blank spots.  I like doing that so there is something there for people to watch during those parts.

thats a good tip.

in my experience clock drift isnt that big of a deal when synching video to audio (not nearly as much as combining two audio sources where slight timing differences can result in massive phase shift and echo)

most modern clocks, while unique in their timing, are generally consistent enough that an hour long audio and video clip can be synched at the beginning and end and the audio stretched accordingly (basically a very slight resample), and then matched up

i try to get a very loud transient like a clap at beginning and end to synch with
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: guitard on January 09, 2021, 07:05:41 PM
I always manipulate the audio to sync to the video.  For the missing parts between clips -- you can use snippets of video from elsewhere during the show or a series of still shots.  Sometimes I take a clip of one of the musicians doing something like head banging and create a slo-mo version and overlay that over the black screen.  There are a few other 'tricks' you can use to cover up the blank spots.  I like doing that so there is something there for people to watch during those parts.

thats a good tip.

in my experience clock drift isnt that big of a deal when synching video to audio (not nearly as much as combining two audio sources where slight timing differences can result in massive phase shift and echo)

most modern clocks, while unique in their timing, are generally consistent enough that an hour long audio and video clip can be synched at the beginning and end and the audio stretched accordingly (basically a very slight resample), and then matched up

i try to get a very loud transient like a clap at beginning and end to synch with

In syncing concert videos - the drummer is your friend.  So I love guys like Charlie Watts, who plays a minimalist kit.  Of course, I also love Neil Peart - but not for syncing purposes because it can be hard to see him at times behind the wall of drums.

With modern recording equipment, I still get a bit of drift.  But we're usually talking a 1/10th of a second for an hour of video.  So it literally takes only a few seconds to fix that.  But you HAVE to fix it, because even though a 1/10th of a second doesn't sound like much -- it's the difference between the drummer holding his drum stick up above his head in the video when it should be hitting the drum - and the stick hitting a drum on time.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: fguidry on January 11, 2021, 09:54:14 PM
I record concerts with a camera, but you can only record up to 30 minutes continuously. I also have to switch batteries after about 1 hour, so after a concert I normally end up with 3 video parts. I record audio separately, so I have 1 separate audio track. Is there free video editing software with which it is easy to synch the 3 video parts with the 1 separate audio track? I would like to leave the separate audio as it is, so prefer that the screen goes black between the video clips. I read a bout Davinci Resolve, but don't know if this software could synch my 3 video parts with my 1 separate audio track. Hopefully someone can help. Thanks in advance!

Resolve requires some pretty hefty hardware, especially on the GPU side. If you're short of compute power you might try the free Shotcut: https://shotcut.org/

Hitfilm express takes more resources but the version I tried a couple of years ago had audio sync built-in: https://fxhome.com/hitfilm-express

Fran
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: juliocruz on January 14, 2021, 07:04:36 PM
Thanks to everyone who took the time to respond to my question! I really appreciate it. Just 1 more question to Sabre, Voltronic and maybe other Resolve users: Is it possible to leave the separate audio track as it is and then synch the 3 video parts to that audio track with the screen going to black between the video parts? Sometimes I have to change the battery during a song and I would rather still hear the audio and have the screen go black than missing part of the song.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: sabre on January 19, 2021, 01:47:37 AM
Is it possible to leave the separate audio track as it is and then synch the 3 video parts to that audio track with the screen going to black between the video parts? Sometimes I have to change the battery during a song and I would rather still hear the audio and have the screen go black than missing part of the song.

Yes, absolutely. The second audio track can continue to run while there are 'gaps' in the video. All decent video editing apps support this feature. There's nothing you need to do in order for this to occur - the video editor will automatically add a black screen where there is a gap in the videos.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: voltronic on January 19, 2021, 07:23:14 AM
Is it possible to leave the separate audio track as it is and then synch the 3 video parts to that audio track with the screen going to black between the video parts? Sometimes I have to change the battery during a song and I would rather still hear the audio and have the screen go black than missing part of the song.

Yes, absolutely. The second audio track can continue to run while there are 'gaps' in the video. All decent video editing apps support this feature. There's nothing you need to do in order for this to occur - the video editor will automatically add a black screen where there is a gap in the videos.

The only thing I would add to this is that you might want to do a fade out / in of a second or two on your video clips going in and out of the black screen sections. This will make things much less jarring at those points. If those places where you are changing your camera battery ever happen to be during song or set breaks, that's also an opportunity to add text titles if you want.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: guitard on January 19, 2021, 08:43:09 AM
Is it possible to leave the separate audio track as it is and then synch the 3 video parts to that audio track with the screen going to black between the video parts? Sometimes I have to change the battery during a song and I would rather still hear the audio and have the screen go black than missing part of the song.

Yes, absolutely. The second audio track can continue to run while there are 'gaps' in the video. All decent video editing apps support this feature. There's nothing you need to do in order for this to occur - the video editor will automatically add a black screen where there is a gap in the videos.

The only thing I would add to this is that you might want to do a fade out / in of a second or two on your video clips going in and out of the black screen sections. This will make things much less jarring at those points. If those places where you are changing your camera battery ever happen to be during song or set breaks, that's also an opportunity to add text titles if you want.

I usually shoot a few minutes of video before/after the show to use as filler during gaps created by things like battery changes, security ducks, etc.  Typically I'll shoot clips of things like the crowd entering/exiting the venue, the merch booth, the mixing board, etc.  If the clip isn't quite long enough to cover the entire gap, I'll stretch it out and make it a slo-mo clip.  You can also do the same thing with still shots, but I prefer the visual aesthetic of video clips.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: juliocruz on January 19, 2021, 07:08:54 PM
Thanks Guitard and Voltronic!
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: juliocruz on January 20, 2021, 05:25:40 PM
Thanks, Sabre! I'm thinking of buying a new computer with high specs that can handle Davinci Resolve.
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: Teen Wolf Blitzer on January 24, 2021, 04:48:54 PM
This thread amuses me.  I started with one cam.  Rolling hdv tape at the time.  This problem you describe is why I now have 8 cameras.  lol.   :banging head:  Oh ya the ONLY answer to your question the the plugin Plural Eyes.  BUY IT!
Title: Re: Synch 3 video parts with 1 separate audio track: free software
Post by: willndmb on May 02, 2021, 11:02:52 PM
Final Cut Pro has built in synch but not free and requires a Mac