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Old 11-25-2022, 08:03 PM   #1
bd32
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Default Any plans to auto sync audio from video to other audio in Reaper?

I have constant problems trying to align the video I shoot at the same time as I'm recording multi tracks on Reaper. I brought this up several years ago and learned a few tricks trying to use alt and drag to align bits that were out of sync. Really hit or miss for me. Today I have a mic recording a percussion instrument in Reaper. My camera is recording video and audio. Even within 15 minutes, if I adjust the video to match the start wav image and use alt/drag to align the back, and also do this in the middle it still gets off very quickly.It would be so happening if Reaper developers could just let the computer analyze the wave form from audio track and do whatever it takes to make the audio from the video match. Thanks.

Last edited by bd32; 11-25-2022 at 08:58 PM.
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Old 11-27-2022, 01:06 PM   #2
papagirafe
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Hi,

Having had little control on video footage in some of my projects, the synchronisation seems very dependent on the equipement used. I would give a shot at re-encoding the recorded audio track to the same parameters/encoding as audio track of the video and look if it makes a difference. If it does then you can then tweak the parameters to improve quality if needed.

Last edited by papagirafe; 11-27-2022 at 02:22 PM.
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Old 11-27-2022, 05:11 PM   #3
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Quote:
Originally Posted by bd32 View Post
I have constant problems trying to align the video I shoot at the same time as I'm recording multi tracks on Reaper. I brought this up several years ago and learned a few tricks trying to use alt and drag to align bits that were out of sync. Really hit or miss for me. Today I have a mic recording a percussion instrument in Reaper. My camera is recording video and audio. Even within 15 minutes, if I adjust the video to match the start wav image and use alt/drag to align the back, and also do this in the middle it still gets off very quickly.It would be so happening if Reaper developers could just let the computer analyze the wave form from audio track and do whatever it takes to make the audio from the video match. Thanks.
I make long videos (1-hour+) using multiple video cameras and Reaper audio almost every week and the sync is never an issue. Your audio rates are probably mismatched. My guess is you are mixing 44kHz and 48kHz audio.
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Old 11-27-2022, 06:04 PM   #4
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I make long videos (1-hour+) using multiple video cameras and Reaper audio almost every week and the sync is never an issue. Your audio rates are probably mismatched. My guess is you are mixing 44kHz and 48kHz audio.
My guess is no, it's not about sample rates. It's because the clocks in the different recording devices isn't running steady. It is common in prosumer devices. However, it could be just one of them, or both.

This isn't mostly going to be a feature in REAPER, but I guess there are external programs that could sync them up. Another option would be to calculate the drift, and pitch the audio recording. But the best option would be to get devices with internal clocks that runs rock solid steady (like the RME Fireface interface that I have).

Last edited by Illusion; 11-27-2022 at 06:09 PM.
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Old 11-27-2022, 06:19 PM   #5
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You need everything locked to a single clock while shooting. There's no way that even the best digital clocks are going to stay in sync over an hour without this.

If you want an easy way to sync things up you could look at stretch markers which allow you to drag the audio to match but the best way sonically is to very slightly adjust the playback speed of the audio items in the item properties dialog. You may need to split the audio into sections with slightly different adjustments for each section but I've synced things up to within a few milliseconds over an hour using this method.
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Old 11-27-2022, 08:20 PM   #6
bd32
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At the minimum these replies point me in the direction I have to go. I was just hoping, since the last time I checked, there might be an automatic way to do this. I have no idea how to code and sometimes it takes all of my ability to even implement some things people do here. If I switch cameras or use my phone it's starting all over again in terms of the format they record in. It's been quite a while since I last tried to sync audio and video and these replies make remember some of the tips I got then.For my level, pretty difficult. I still hope someone will bring auto sync for video and audio, for Reaper, in the future and/or allow me to record video directly into Reaper as I record multi track audio and just let me avoid the whole snyc issue. Thanks.
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Old 11-28-2022, 09:19 AM   #7
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Originally Posted by bd32 View Post
At the minimum these replies point me in the direction I have to go. I was just hoping, since the last time I checked, there might be an automatic way to do this. <snip>
I have seen a lot of discussions about sync'ing multiple audios in audio forums and I haven't seen any automatic option. From experience, it is better to "loosely" sync using audio from the video track to match the pure audio track: the eye is slower than the ear. I would suggest your listen to the Reaper video about transcient guides that will save you a lot of time. Good luck.
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Old 11-28-2022, 04:49 PM   #8
bd32
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Quote:
Originally Posted by jamesp View Post
You need everything locked to a single clock while shooting. There's no way that even the best digital clocks are going to stay in sync over an hour without this.

If you want an easy way to sync things up you could look at stretch markers which allow you to drag the audio to match but the best way sonically is to very slightly adjust the playback speed of the audio items in the item properties dialog. You may need to split the audio into sections with slightly different adjustments for each section but I've synced things up to within a few milliseconds over an hour using this method.
I'm just trying to recall how to use these. I tried a few in the most recent video but it seems I'll need many. In a very general sense, about how many stretch markers might I expect to have to stick in for an hour video? Just to get a rough idea. Thanks
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Old 11-28-2022, 04:46 PM   #9
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I make long videos (1-hour+) using multiple video cameras and Reaper audio almost every week and the sync is never an issue. Your audio rates are probably mismatched. My guess is you are mixing 44kHz and 48kHz audio.
Well, I kind of learned about that the last time I tried this and all the tricks needed are slowly starting to come back. That's right about mixing 48khz and others in my case. I had two projects with different ones. I thought I'd set project settings in Reaper for 48 to match my camera (which can't be changed from 48khz) but missed one checkbox and got another mismatch. Regardless, yesterday I got all audio recording tracks on 48 to match the video and it's still drifting a lot over one hour. So that was disappointing.I'm trying to familiarize myself with stretch markers now. Thanks.
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