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Sneaking Past Heavy-Handed Audio Compression on YouTube
niceone writes "Recently YouTube seems to have started applying extreme compression
to the audio of uploaded clips. This is the type of compressions used
by radio stations to make everything louder, but in this case applied
extremely badly. In quiet passages, breathing and shuffling become
overpoweringly loud. A gently plucked guitar chord becomes a distorted thud.
Listen to an example here. And here's what it could sound like — still not perfect, but a whole lot better. The
fixed version is thanks to a workaround proposed by
Sopranoguitar — the idea is to turn down the audio and mix in
a high frequency sine wave (I used 19kHz). The sine wave fools YouTube's
compressor into thinking that the file is at a uniform level (and does
not need the volume changing at all) but is filtered out by the encoding
process (so, no need to worry about deafening any dogs)."
Wouldn't it be easier to set your gate correctly? Cut out the background sounds BEFORE submitting to youtube; do proper editing and then it doesn't matter so much what they do. Here, in my opinion, is a good site for all such information.
Qxe4
Well, it starts with the "Loudness War" Record companies/radio stations compete to make everything louder, because the louder the music is coming over the air, the more likely the listener is to notice it. I don't see how that would help youtube though, because we're not listening to youtube in the background like we are to the radio.
After some more testing it seems that there is a problem with high quality mode. With the tone and sample rate I used (19kHz and 44.1k) at least the high quality encoder whistles at, some other frequency. Sounds like somewhere less than 10kHz to me.
I hope YouTube fix this soon.
ccalam - acoustic versions of new songs.
Sure, how about the given example? One second is really all you need.
In the heavily compressed one, you hear an annoying hiss and the sound of the microphone being moved for the first few seconds.
In the non-heavily compressed one, you don't.
That's really the complete example without having to listen to the song. Really, the first few seconds are the best example, because Google is apparently amplifying almost complete silence to noise. The song part really doesn't help much. (Or at least, as much as I was willing to listen to it, which was only a few seconds.)
You are in a maze of twisty little relative jumps, all alike.
Wouldn't another solution be to sneak past the entire recompression process by submitting a .flv video that meets YouTube's requirements to avoid recompression? Or would the compression on audio (not the same type of compression, the one this article is talking about) still be forced on these?
By the way to improve the trick, what you could do is detect the envelope of your sound, a modulate your 19 kHz sine with an envelope complementary so that the two envelopes would sum up to a flat line, so your 19 kHz envelope would be f(t) = 1 - original_sound_envelope(t).
You just got troll'd!
YouTube is just trying to enforce a standard level of quality to the content. Everyone expects crappy video with lots of compression artifacts, so the audio might as well follow suite.
Better known as 318230.
Can someone post an example I could possibly listen to for more than one second?
No
Table-ized A.I.
you mean that high pitched squeal that is driving me nuts in the example more then the audio compression? Yea.. that's filtered out all right...
Defective Logic
Ruff ruff rufff, and ruff rufff, you little bigoted ruff ruff ruffff.
Translation : I'm ultrasound-deaf, you insensitive clod!
You just got troll'd!
youtube is a huge money sink. They probably can't afford to hire people that have experience in audio compression, test different algorithms, etc. As to why... video and sound quality varies a lot, so they probably are trying to make everything more equal, so the viewer doesn't need to adjust their volume for every video.
Do you even lift?
These aren't the 'roids you're looking for.
The worst examples I've seen have been videos of a lecture/speech, and while the main speaker has a microphone it also picks up sound from around the auditorium or lecture hall.
Normally this is fine as we have all become accustomed to faint background noise, with this extreme compression the faintest cough or shuffling in the audience sounds is as loud as the person speaking and is thus very distracting.
Considering most of the lectures I view are 30+ minutes long this really pisses me off.
The high quality version of the audio will have the 19 (or up to 22.1) kHz sine wave you choose to use in your video upload. So this is a trade-off of quality (high-quality = eek!) versus lack of unwanted range compression (low-quality = listenable, for lack of a better word).
FWIW, I can hear 19 kHz waves. So this trade-off affects me.
It surprises me after all these years, audio formats don't provide recording information about the dynamics of the waveform.
Cameras write EXIF information into JPEG files, why can't we have something similar for audio so we don't have to adjust the volume all the time?
You don't have to be an audiophile to appreciate good audio. I have a custom amp next to my computer into which I've plugged headphones. Find anyone with a pair of headphones, and you'll find an amp, too. Either that, or a deaf person who's been tortured by a bad Flash file.
It would be nice if YouTube offered some choices, such as volume adjustment
Yeah, I mean, who on YouTube would even think of abusing that?
You just got troll'd!
I have to keep jacking the knob up and down.
To YouTube videos? Sicko!
I don't think YouTube is trying to run a loudness war, but rather trying to fix up a lot of amateurish recordings that are uploaded with bad audio. I can't tell you how many recordings on the net are either way to quiet (e.g. I can't hear speech even at max volume) or too loud and that change in mid-video (e.g. person walks away from or closer to mic). Despite their good intentions, though, it seems to have fallen prey to the "Clippy" effect.
What YouTube needs to do is have a little check-box on uploads that indicates whether to apply the auto-balance. And in case an uploader asks for no auto-balance when they really shouldn't (e.g. they think they know but don't) there should be a side link to listen to the auto-balanced version.
To YouTube videos? Sicko!
What can I say? Unrehearsed rants into webcams really turn me on...
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
I have indeed heard of such deterioration on the Teen Buzz website (which is currently down for excessive bandwidth usage?) - but this page describes it as well.
Those little annoying sine-wave sounds are also used by TV advertisers such as Kentucky Fried Chicken to grab teens' attention if adults are not their market. (For the record, if you can't hear the tone, it sounds off when the KFC bucket shows up.)
I guess they are trying to compensate for the huge differences between recording quality in the videos people submit. Some are loud enough, others are very low and you have to turn the level way up to understand what people are saying.
They could simply normalise the level, but if you have a speech with very low level and the guy drops the microphone in the middle, that one peak is so loud that will make the normalisation process useless.
But compression is such a complex and subjective issue that it should be performed by hand. I guess they have an automated process for that, and it doesn't have any intelligence, just steamrolls all the audio it finds, whether it's speech, music, or anything else.
they could have the volume knob (optionally) adjust to the appropriate volume for a given video.
They do, it's called compression.
Louder is one thing, compression is another.
Compression can help bring out the faint natural harmonics in a sound, making it "warmer", not unlike an overdriven tube amp. These harmonics are like ear candy to most people, subliminally making the sound more enjoyable.
Radio stations do it for various reasons, one is it helps them sustain peak output power. Another is that the average radio is a cheap chinese gadget that sounds like liquid ass, so the compression actually helps with the sound quality on those devices. When you also consider where radio is often heard, e.g. malls, outdoor venues, cube offices, you realize these are all substandard listening environments where high dynamic range really means you lose half the sound, so the compression again helps with perceived quality by driving most of the content above the noise threshold.
There are plenty of good reasons for sound compression, but its use should be toggled by the user, and for the love of god, give it some sane thresholds! For most content, anything above 4x compression is overkill!
-Billco, Fnarg.com
But what if you move away from the mic to breathe ?
Chocolate Rain
*whoooosh*
Youtube makes my breathing loud again
Chocolate Rain
*whoooosh*
My eardrums are whimpering in pain
-Billco, Fnarg.com
The typical youtube uploader can't even manage to tag their videos properly. Giving them MORE options is just dangerous.
Username taken, please choose another one.
This is just in. Studies have shown that on a popular site named Slashdot LOUD COMMENTS ARE MODERATED BETTER THAN QUIET ONES!!!
Although I tend to think that Dan East summed it up best, I feel the need to point out that 95% of bad YouTube audio is the result of lousy recording quality, not subsequent processing.
Garbage In, Garbage Out.
The mics and electronics on most consumer camcorders (or that most people use with their Macs and PCs) are just plain crappy, and shouldn't be relied on for anything that you hope to distribute. And of course, some actual audio recording skills help too.
Three Squirrels
Compression can help bring out the faint natural harmonics in a sound
Only a multiband compressor can do this, otherwise it just raises the level of all harmonics by the same amount.
If the one on YT is fooled by a 19khz sinewave then its single band compressor.
3:1 compression is usually considered the upper limit for practical purposes. Most people do prefer a small amount of compression.
WPLJ 95.5 in NYC knew this very well back in the 70's they' use massive audio compression to keep the modulation index of the carrier at 95.5%... That needle just say there!
My station WDJF 107.9 Westport CT cared about audio quality. The MI followed the full amplitude of the source audio. Fed by 2 channels of full 15 khz equalized ma-bell-telco pairs. We sounded good! But PLJ was much much louder.
Then hide the options. You don't protect the idiot by rubber-coating all the corners in the room, you protect them by putting the knives out of reach.
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
Technically compressors don't raise the level either, they reduce it. It's the make-up gain afterward that raises the level.