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Ask Slashdot: Synchronizing Sound With Video, Using Open Source?
An anonymous reader writes: I have a decent video camera, but it lacks a terminal for using an external mic. However, I have a comparatively good audio recorder. What I'd like to do is "automagically" synchronize sound recorded on the audio recorder with video taken on the video camera, using Free / Open Source software on Linux, so I can dump in the files from each, hit "Go," and in the end I get my video, synched with the separately recorded audio, in some sane file format. This seems simple, but maybe it isn't: the 800-pound gorilla in the room is PluralEyes, which evidently lots of people pay $200 for --and which doesn't have a Linux version. Partly this is that I'm cheap, partly it's that I like open source software for being open source, and partly it's that I already use Linux as my usual desktop, and resent needing to switch OS to do what seems intuitively to be a simple task. (It seems like something VLC would do, considering its Swiss-Army-Knife approach, but after pulling down all the menus I could find, I don't think that's the case.) I don't see this feature in any of the Open Source video editing programs, so as a fallback question for anyone who's using LiVES, KDEnlive, or other free/Free option, do you have a useful workflow for synching up externally recorded sound? I'd be happy even to find a simple solution that's merely gratis rather than Free, as long as it runs on Ubuntu.
What you want is a simple Hollywood style clapboard. Use any two track + video editor and visually line up the audio spike to the video frame where the board is closed.
That is what the movie claps you see in documentaries are for. You produce a clap with your hand, resulting in a spike in your external mic and in the video cameras mic. That way, you know where to sync the two in your favorite video editing tool and you're fine. No need for special software or something similar.
Your issue is very similar to what Twitch streamers go through with delay between audio and video. I'd suggest checking out OBS and there are quite a few how-to videos on YouTube to show you how to sync.
Don't sync to the video, sync to the audio. Your video recorder records the audio "reference" track and you just sync your externally recorded audio to the reference track. Kdenlive has this feature. Other editors may a well.
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"You are not remembered for doing what is expected of you." - Atul Chitnis
mencoder will do exactly what you need, muxing separate video and audio tracks into one container file of your choice, with tunable offsets for each track.
https://github.com/allisonnico...
I use avidemux and audacity to add Rifftrax to movies. Basically copying out the existing audio, merging the rifftrack with the movie audio in to one track and then putting it back in as a separate audio track so the original audio is there too if you want to watch the movie without jokes (pretty rare for me actually, but it's nice to have options ;)).
Someone else already suggested OBS, I've used that too for recording gaming video. It can be pretty intensive and it takes some fiddling to make it workable but it's not bad.
He is correct. AV is my job, and I do a lot of it on Linux.
My multi-track audio recorder and my video claim to run at the same speed - but there is variance between any two clock sources that are not linked.
I use Harrison Mixbus (an excellent Linux/Mac/Windows DAW) and XJAdeo, both slaved to the Jack clock. You can shuttle audio and the video tracks your position according to the audio elapsed time.
The two clocks drift apart very slowly. For the purposes of syncing live music footage, you only need to make a small correction to the audio every five minutes or so to keep things together.
If you don't want to pay for Mixbus, you can use Ardour - it's getting very useable these days.