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Fix Audio Sync in OBS

Ever notice a live stream that has audio a little off from the video?  We’ll help you fix that when broadcasting with OBS Studio.

You often hear audio issues called “lag.”  However, that term gets confusing since many people use it as a catch-all phrase.  Let’s define when people say lag, but really mean…

Latency  Latency is the term we use to describe the time it takes from the broadcaster to send his or her stream up to the internet, travel across the planet, and get pulled down to the viewer’s computer.  Many factors determine how long this can take, anywhere from a few seconds to 20 or more seconds.  This time is based on the internet speed of the broadcaster AND the viewer.  Different viewers will experience the live broadcast at different times than other viewers.  As a broadcaster, you all have experienced this when you ask your audience a question and have to wait until they respond.  Improving latency is a factor of improving your internet connection (upgrading to a better ISP or broadband connection); and reducing the amount of data your stream (turn down your broadcast quality).  We’ll go into more detail about improving latency in another blog.

Audio Sync  Audio Sync is today’s topic.  It is the synchronization of the audio with the video.  When the audio and video get “out of sync,” you witness the phenomenon where you see the lips move but hear the voice slightly later, or vice versa.  It is like watching a badly dubbed foreign movie.  There can be a number of contributing factors why this occurs, but the chief reason is a slow computer / CPU.  It takes more cycles, or computing power, to process video than it takes to process audio.  The audio is often ready to stream slightly ahead of the video.  When a chunk of audio data gets combined with a chunk of video data that represents two different points in time, the broadcast will be out of sync.

OBS is great broadcasting software and handles many sophisticated internal features.  It typically requires more computing power than simple one-cam broadcasting from within a browser.  Audio Sync issues do appear more often when broadcasting with OBS.  However, there is an easy fix to this problem (without having to upgrade your computer to a monster size CPU and GPU).

In OBS, adjust the “Audio Delay” to bring the timing of the audio precisely in with the video.

On the main screen, click on the Audio Mixer.  (Below are two images, one from OBS v18 and one from v20. They slightly changed the way to open the Audio Mixer between updates.)

OBS v18 – click the Mixer gear icon in middle of screen

v18 – Audio Mixer Icon, click image to enlarge

 

OBS v20+ – click the Mixer gear icon next to your audio device, then choose Advanced Audio Properties

v20+ – Audio Mixer Icons, click image to enlarge

Audio Mixer Menu, click image to enlarge

 

Find the audio device you want to adjust and enter the number of milliseconds (MS) to slow down the sound.

Audio Delay, click image to enlarge

 

Recommended Approach:

  • First, fire up your webcam and microphone.  You should see the video output in the main screen of OBS.
  • Start Recording your stream locally. In other words, DO NOT START live streaming.
  • Perform a short bit by speaking slowly into the camera so you can watch your lip-sync closely later.  Clapping your hands is another good technique to dial in the sync.
  • Watch the recorded video to get a sense how far off the sync is.  Most likely, you will hear the audio first, and then see the video catch up.  It’s tricky at first to tell which way the sync is messed up (sometimes the video comes first and the audio is behind).  But you will get the hang of it.
  • Adjust the Audio Delay for your specific mic by adding a number of milliseconds.  Start with 30ms.
  • Record another video and check the sync again.
  • Repeat this process until you can not notice any sync problems.  Use 30ms increments when adjusting.  For instance, if on the first try 30ms did not fix the sync, next time try 60ms, then 90ms, etc.
  • Last, you can also adjust the Video Delay in OBS v20+. Same principle applies here, too.  Adjust small amounts, record, check, repeat.

When you are all done, you are ready to live stream.  OBS will remember your delay settings for the next broadcast.  But it is good practice to occasionally recheck as your audio/mic setup may have changed in your studio, your computer may have upgraded to newer software, and so on.

A note about “video delay” and your studio sound setup.  For musicians who use a sound board, mixers, auto-tuning, delay pedals, etc; the audio delay may be attributed to the processing in the sound system itself – and not in OBS or your computer.  This is generally the cause when video comes in first and the audio comes in behind.  The fix here is to delay the video so it slows down to match the audio.

Tips when Broadcasting from Public Venue

Live Show

We love it when StreetJelly musicians broadcast their public performances.  But it takes a little extra care to produce a decent show.  Below are three main areas to consider when setting up a successful streaming event.

WiFi

Biggest thing to remember, not all wireless internet, WiFi, is created equal.  In fact, public WiFi is notoriously slow in many venues.  The local wireless router at a club or coffee house is usually dialed down to prevent any one person, or group of people, from hogging up the entire bandwidth.  Most small WiFi routers just can’t handle everyone camping out at a table, sipping coffee, and watching YouTubes all day long.  A slow internet connection will cause your StreetJelly video to be choppy or freeze, and make your sound cut out often.

What to do?

  • Test, test, test.  Go to the venue ahead of time and test their WiFi connection.  Make sure their internet is fast enough to broadcast and receive video.  Also, test during peak times when there are a lot of people in the building.  Everyone of you will be competing for the same bandwidth.  Use the StreetJelly broadcast-testing page to analyze how well you can broadcast.
  • Talk with the venue owners.  For one, you should already have permission to broadcast from their location, right?  Many times, a venue will have another password-protected WiFi network they use for themselves.  Ask if they have a second fast and reliable connection to the internet you can use.  They will probably be happy to help as you certainly can help promote the local venue in your show.  “Come on down, it’s Happy Hour at the best pizza joint in town.”
  • Another option, bring your own WiFi.  Most cellphone carriers offer 4g Hotspot or MiFi devices.  These work great and almost always guarantee a very strong internet connection (unless you are way out in the boonies).  But beware, this is expensive and data charges can add up quickly.  Most data plans ($50-80/mth) often limit 5 to 10 gigs of data transfer per month.  A typical one-hour streaming broadcast can use up to 1 gig of data transfer.  The penalty fees can be outrageous if you go over your limit.

Sound

Just as important as a good internet connection is your sound.  (I love stating the obvious.)  However, getting a public performance to stream well over the internet is much different than streaming from your living room.  We try to make StreetJelly as easy as possible to broadcast from home – a typical guitar player / singer can do well with a simple USB microphone like the Snowball or Meteor podcast-style mics.  Being in public, however, you are most likely using a lot more equipment to get a good and loud sound in the venue.  You cannot rely on your computer’s mic to pick up that sound well to broadcast upstream.  You will need a way to get the sound out of your equipment into your computer.  Most built-in computer mics, and even the better USB mics, can only pick up sound within 10 feet or less.  In a large room, even with high volume, these mics will pull in a dull and muddy sound.  Folks are tempted to turn up the input levels, but only to find they pick up more ambient noise (people talking, dishes clanging) with no improvement to their music.

What to do?

  • Do not use the built-in mic on your computer – never for a public broadcast.
  • Only use a USB podcast-style mic in a small intimate setting, like a coffee house, with very little background noise.
  • Use the output from your mixer to feed directly into your laptop.  An external device that can mix your sound and produce a single source to your computer works best.  Here’s an example of a “mini-mixer” device, the Alesis MultiMix 4-Channel USB Mixer.  It does a good job and is very easy to set up.  (Please note: we mention these products only for your convenience.  There are many similar products out there.  If you have used any to success, tell us below in the comments.)
  • Test at home.  It could be hard to test your full setup ahead of time at a nightclub, so best to get the feel of everything at home first.  Try your garage or wide open basement.  That will best simulate the horrible bouncing conditions you may encounter in a restaurant or club.  Set up your mic, amp, mixer, everything.  Jam as loud as you would in public.  Then test broadcast on StreetJelly’s test page and have a friend help confirm your sound settings.

Overall Package

Performing live to a public crowd, large or small, is not the same as broadcasting and chit-chatting on StreetJelly from your couch.  To think you can “throw up a webcam” at your next open-mic and hope everything is good enough; will be very disappointing.  At best, you will get the “webcam in the corner” affect on StreetJelly.  You’ve all seen this a hundred times.  A band is “streaming live” at some club – but the show is terribly boring as you only see the one tiny cam image from somewhere in the club’s rafters, and the musicians never looking into the camera.  StreetJelly viewers will get bored and not stay long …and not tip much, either.

What to do?

  • Frame yourself in the camera as best as you can, and as close as you can.
  • Remember you are performing for two audiences; the one in front of you and the one on StreetJelly.  Talk to both parties.  Even a simple acknowledgement can make all the difference.  Part of your skill as an entertainer is “working the crowd.”  Do it.
  • Get a friend to man your StreetJelly chat.  If you can not have your laptop close to you on stage, get a friend to chat for you.  The StreetJelly viewers will understand if you can’t read, type, and perform all at the same time.  But having a friend by your side to answer questions, tell everyone the name of the venue, the songs you are playing, etc., will translate into a nice experience for all those online  …and hopefully more tips!

Final thoughts.  As much as you practice your vocal range, picking skills, and songwriting ability; performing in front of an audience is also part of your craft.  Work it, practice it, and perfect it.

Any musicians with experience streaming from a public location? Please add your insights below in the comments.