YouTube Upload Sound Alteration

Mr. Jelly · #1 09-09-2023, 08:00 AM

Speaking with a friend that has a recent video system installed in his music venue. He said they are having trouble with the sound quality changing when they post performances on YouTube. He mentioned mp4? I really don't have any more information than that. Any thoughts?

jim1960 · #2 09-09-2023, 08:38 AM

Quote:

Originally Posted by Mr. Jelly

Speaking with a friend that has a recent video system installed in his music venue. He said they are having trouble with the sound quality changing when they post performances on YouTube. He mentioned mp4? I really don't have any more information than that. Any thoughts?

Most likely he's hearing the effects or YouTube normalizing to -14LUFS. No matter how loud or quiet your submission is, YouTube is going to change the volume so it averages about -14LUFS.

We perceive louder things as sounding better, so playing back a track at the original volume and comparing it to what YouTube outputs, most people will say YouTube sounds worse.

Glennwillow · #3 09-09-2023, 11:08 AM

I set my mastering up for -14LUFS so that when I upload to YouTube, it sounds pretty much the same.

- Glenn

Doug Young · #4 09-09-2023, 12:25 PM

I haven't kept up on all the details of You Tube (a moving target, and not always documented). But last I knew, You Tube was doing a good job on audio IF you upload videos in HD, at least 1080. 4K is better. Below that, at least at one point, they were streaming sound in mono. Best bet is to level your audio at -14LUFS, and upload the highest quality video and audio you can. I wouldn't upload mp3 audio, for example, where you've already converted it to a compressed format and then they may convert it again. (Tho You Tube accepts mp3)

This seems to be the latest official guidlines:

https://support.google.com/youtube/answer/4603579?hl=en

keith.rogers · #5 09-09-2023, 01:47 PM

The better quality you upload, the better the chances of it sounding closer to the original, but it depends a lot on the mix you upload. My short answer is mix/master to their target LUFS (as Doug said), and create HD (1080p or higher - "HD" no longer includes 720p at YT) with embedded FLAC (non-lossy) audio. It will at least give the viewers a chance at whatever YT is calling their best quality.

BUT, the viewer could still get 128kbps (lossy AAC) if they're watching at SD, or maybe even worse, if YT detects a slow/limited bandwidth connection. Then they're not going to default to HD/4k, but something that they feel will not glitch or hang.

Doug Young · #6 09-09-2023, 02:08 PM

Quote:

Originally Posted by keith.rogers

BUT, the viewer could still get 128kbps (lossy AAC) if they're watching at SD, or maybe even worse, if YT detects a slow/limited bandwidth connection. Then they're not going to default to HD/4k, but something that they feel will not glitch or hang.

That's a good point. Even tho I have good internet, and have you tube set to the highest quality, every now and then they still show me something in 360p, with noticeable video and audio quality loss. So if something sounds worse, check the settings on that video.

rick-slo · #7 09-09-2023, 03:48 PM

The above posts are right on. Also at least on my computer the program I use for making a video/audio there is a choice to optimize it either for the audio or video part. I always do that for the audio.

KevWind · #8 09-10-2023, 03:59 PM

humm lots to unpack very little info and a lot questions

first (assuming the sound quality "changing" means less quality ) then how is he comparing it ..In other words is he listening to the YT video on the same sound system that he is saying it is changing from ?

I have not heard of a "video system" do you mean he has set up a video camera ? What resolutions is he shooting video in,,, hopefully 4K

Does he use an audio recording system for the sound part of the video (like say a DAW system ?) as opposed to using the camera audio

Is he using a video editing program , where he can sync the audio from the recording system to the video ?

YT will compress the video so it pays to upload the highest rez you can (to a point). for the audio part as Glenn mentioned YT will compress louder audio to -14 LUFS or if it is very quiet they will boost it. Either way the algorithm will almost invariable reduce the sound quality So the closer you audio is to -14 LUFS the less YT will mess with it

Also I have read that if ---when up loading high REZ video like 4K to YouTube, if you choose to schedule the publishing for the next day that YT will use the better processing format than if you don't schedule it and YT starts processing while you uploading .

DupleMeter · #9 09-11-2023, 07:23 PM

I do a lot of audio post for some of the bigger audio companies and do weekly livestreams for clients, I have had to become an expert on YouTube audio. Here's what I've learned.

YouTube's audio specs are:
-14 LUFS (program integrated)
-1.0 TP

What this means is that the total average Loudness Units Full Scale (LUFS) measured via the EBU/ITU-1770 standard (vs. DialNorm, which some streaming services use) should be -14. It also means that the highest peak (reconstructed via 4x oversampling) cannot exceed -1.0dBFS. You'll need a specific True Peak Limiter to assure you don't exceed this.

As stated, if you're audio is louder than the -14LUFS integrated measurement, YouTube will lower your playback level to meet this spec. But YouTube will not raise your level to meet this spec. So, if your audio is below the spec it will playback softer than other content.

YouTube does roll off audio above 17k so that your a good -6dB down at 20k. Probably not a big deal, but it should be noted. However, low end is not attenuated & YouTube will playback all the way down to DC...so make sure you aren't giving up any of your loudness to unheard low end (I mean, even the best computers have a steep low end roll off because of their small speakers).

If you right click on a YouTube video you can choose "Stats for Nerds" on any video to see the current settings that YouTube is applying. I wish I could just drop a screenshot of this here, but I have to host it somewhere & I just don't want to deal with the hassle right now.

The important numbers are the: Volume / Normalized stats which might look like this:

Volume / Normalized: 100% / 100% (content loudness -6.3dB)
- I Just grabbed these numbers from one of Lee Sklar's videos.

So what that is telling you is that the current YouTube player volume is set to 100%, the content is playing back at 100% of that volume and the content is -6.3dB under the -14LUFS spec. So, you can clearly see that the volume has not been raised to meet the spec.

So, the key is to deliver a good mix that meets the spec (within a dB in either direction). It's really not too hard, if you're used to delivering mixes to a spec. It's just one more spec to have to include in deliverables. It's harder for livestreams, and it took me a while to work out how to deliver live mixes that were consistently hitting the standard, but it's very possible. I found having the right metering helped a ton.

HTH

FrankHudson · #10 09-11-2023, 08:46 PM

DupleMeter, that's a super helpful post. Thanks!

phcorrigan · #11 09-11-2023, 10:50 PM

Quote:

Originally Posted by DupleMeter

I do a lot of audio post for some of the bigger audio companies and do weekly livestreams for clients, I have had to become an expert on YouTube audio. Here's what I've learned.

YouTube's audio specs are:
-14 LUFS (program integrated)
-1.0 TP

What this means is that the total average Loudness Units Full Scale (LUFS) measured via the EBU/ITU-1770 standard (vs. DialNorm, which some streaming services use) should be -14. It also means that the highest peak (reconstructed via 4x oversampling) cannot exceed -1.0dBFS. You'll need a specific True Peak Limiter to assure you don't exceed this.

As stated, if you're audio is louder than the -14LUFS integrated measurement, YouTube will lower your playback level to meet this spec. But YouTube will not raise your level to meet this spec. So, if your audio is below the spec it will playback softer than other content.

YouTube does roll off audio above 17k so that your a good -6dB down at 20k. Probably not a big deal, but it should be noted. However, low end is not attenuated & YouTube will playback all the way down to DC...so make sure you aren't giving up any of your loudness to unheard low end (I mean, even the best computers have a steep low end roll off because of their small speakers).

If you right click on a YouTube video you can choose "Stats for Nerds" on any video to see the current settings that YouTube is applying. I wish I could just drop a screenshot of this here, but I have to host it somewhere & I just don't want to deal with the hassle right now.

The important numbers are the: Volume / Normalized stats which might look like this:

Volume / Normalized: 100% / 100% (content loudness -6.3dB)
- I Just grabbed these numbers from one of Lee Sklar's videos.

So what that is telling you is that the current YouTube player volume is set to 100%, the content is playing back at 100% of that volume and the content is -6.3dB under the -14LUFS spec. So, you can clearly see that the volume has not been raised to meet the spec.

So, the key is to deliver a good mix that meets the spec (within a dB in either direction). It's really not too hard, if you're used to delivering mixes to a spec. It's just one more spec to have to include in deliverables. It's harder for livestreams, and it took me a while to work out how to deliver live mixes that were consistently hitting the standard, but it's very possible. I found having the right metering helped a ton.

HTH

Thanks! A great explanation!

I now need to learn to use a true peak limiter.

keith.rogers · #12 09-12-2023, 07:45 AM

Quote:

Originally Posted by phcorrigan

I now need to learn to use a true peak limiter.

iZotope's Ozone has a "Maximizer" module that does it all for you. Set your target LUFS, click on True Peak, "Learn," and then just let the whole audio track play.

I just want to note that -14dB LUFS is the max, and YT will adjust down, but it's not a rule that you should master everything to that number, because not everything will sound its best there, especially something that might have a lot of just talking/voiceover content. That's probably going to sound like yelling at -14dB LUFS!. But as noted, use "stats for nerds" see what other, popular videos of the same type measure. (FWIW, I just grabbed a Rick Beato interview with Julian Lage, and it was -8.8dB.)

Mr. Jelly · #13 09-12-2023, 07:46 AM

YouTube's audio specs are:
-14 LUFS (program integrated)
-1.0 TP

I have to admit I thought I knew stuffs, but this is talking over my head. How would you suggest an everyday hack to go about it to get by?

phcorrigan · #14 09-12-2023, 08:58 AM

Quote:

Originally Posted by Mr. Jelly

YouTube's audio specs are:
-14 LUFS (program integrated)
-1.0 TP

I have to admit I thought I knew stuffs, but this is talking over my head. How would you suggest an everyday hack to go about it to get by?

The free YouLean loudness meter will help with the LUFS part:

https://youlean.co/youlean-loudness-meter/

My quick research on true peak limiters shows several dedicated ones available. Also, the limiter in Studio One has a true peak function.

DupleMeter · #15 09-12-2023, 03:41 PM

Quote:

Originally Posted by Mr. Jelly

YouTube's audio specs are:
-14 LUFS (program integrated)
-1.0 TP

I have to admit I thought I knew stuffs, but this is talking over my head. How would you suggest an everyday hack to go about it to get by?

Depending on what DAW you use, Pro Tools has a great true peak limiter that also gives you Integrated, Short terrm & momentary LUFS, called the Avid Pro Limiter. Others may too.

As mentioned, YouLean works & has a free version. If you want help with getting to spec, Waves WLM Plus is usually about $35 & will help you hit any target you want with the press of a button. WLM is also a True Peak limiter.