I’m using Windows 7 64 bit, and Audacity 2.1.2
I make let’s plays on youtube and use Audacity to record my voice and OBS to record video, I have on occasion forgotten to stop recording my voice on OBS after doing a sync check.
The audio from an OBS voice recording stays proper with the video, but the audio from a Audacity voice recording gets desynched from the voice in the OBS recording. I want to use Audacity to record my voice for higher quality.
For some reason Audacity is speeding up my voice recordings, and because of this it is synchronizing from my video recordings.
when I installed this version I reset the preferences to default, but that didn’t help the issue. There are times when I’m not saying anything, and Audacity seems to be shrinking those points very unhelpfully. I have to manually recreate those silent moments in editing my videos right now to resync the video and audio many times for each video.
I want to know if there is some setting or something to force Audacity to record the proper length of audio without shrinking any of it. I don’t need it skipping silent parts in my recording, i just need it to stay synchronized so I can speed up my video editing.
I presume that there is no physical or electronic synchronisation mechanism between your two recording systems (such as a common “Word Clock” https://en.wikipedia.org/wiki/Word_clock) - in other words, the two recording systems are freewheeling?
it’s a Dynex usb microphone, idk the model number. but when recording a recent video I was on a call with someone on skype and they also recorded with Audacity. My voice was desynced between their recording and my recording because I could hear my voice in the background of their recording which is perfectly synced with my video recording. I don’t think it’s the mic at that point.
My new mic that I’ll be switching to once the power supply arrives is a Audio-technica AT2020 condenser microphone.
If I sync it at the start only, then by the end there can be as much as 10 seconds or more of desync over the course of a 25 minute video. On average I think there’s about 5-9 seconds total desync at the end. If I have both audio recordings using my voice then I sometimes notice my voice getting more and more out of sync while I’m talking.
Unfortunately, the “clock” built into consumer level devices are often not very accurate, so when you intend to record with a sample rate of 44100 Hz, you may actually be recording with a sample rate of 44099 Hz or 44101 Hz. Differences between the sample rates of different devices will cause them to drift out of sync.
The professional solution to this problem is to synchronise all devices to a single, very accurate “word clock”. Sadly this is only available with expensive hardware.
The alternative solution is what was used before digital recording - to use a “clapper board”.
It does not need to be an actual “clapper board”, just a distinctive mark at the start and end of the recording session.
Fortunately, although consumer level devices may not run at exactly the correct speed, they do usually run at a fairly constant speed (it’s a big problem if they don’t, so keep your fingers crossed that they are running at constant speed). This means that you can import all of the recordings into Audacity, then use the “Change Speed” effect to stretch or shrink tracks as necessary so that both the start “clapper board” mark and end clapper board mark line up correctly.
Import audio files from two devices (call them “A” and “B”). If “A” is synchronised to video, we will make that one the “master” and synchronise track “B” to it.
Use the Time Shift tool to align the start clapper board mark in track B to track A.
Add a label at the start clapper board mark (this makes the next steps a bit easier)
Select from the start label to the end clapper board mark in track A (“master”) and note the duration in hh:mm:ss +samples in the Selection Toolbar.
Select from the start label to the end clapper board mark in track B.
That doesn’t explain why OBS can record in real time, while audacity speeds up the audio though, or how when I recorded with a friend over skype, their audacity didn’t do that either, their Audacity kept recording in real time, without speeding it up.
Yes it explains it. Different computers and presumably different recording devices. Slightly different actual clock rates. Different applications recording different parts of the same stream.
If you had captured the audio with OBS, I am guessing it is more likely that the audio would not have desynced. If so, that gives you another option instead of Change Speed. Add FFmpeg to your computer, drag the OBS video-with-audio file into Audacity to import the audio, edit the audio, then remux the edited audio losslessly into the video using Avidemux.
Alternatively if you run two instances of OBS it may be possible to make OBS record audio and video separately. But that might be more prone to speed drift in the audio.
Apparently I don’t need to worry anymore. My new microphone, the Audio-technica one, is recording properly in real time with audacity. I just started to do what you suggested, and once I synched the beginning clap(i count to 3 and clap to sync) the end clap was already at the right point.