Sneaking Past Heavy-Handed Audio Compression on YouTube 234
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)."
Re:and who came up with it? (Score:5, Interesting)
Just sneak past the entire recompression process? (Score:5, Interesting)
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).
Hans (Score:1, Interesting)
I upload already compressed FLV and find that the video has the same audio quality as I had encoded.
Brilliant idea though. hmm..I remember an episode of Batman Beyond where the Shriek used sound waves to destroy stuff and he even masked other waves. This is off-topic but maybe youtube compressor can be used as a weapon to increase the frequency to a point where glasses may break and dogs can be made deaf, hmm..
but is filtered out by the encoding process (Score:3, Interesting)
Warning from ccalam in the second video (Score:5, Interesting)
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.
Lack of Choices (Score:2, Interesting)
It would be nice if YouTube offered some choices, such as volume adjustment, no volume adjustment, and also other things like stereo. The only way I know of to get stereo is to submit it in Adobe's proprietary formats. YouTube is pulling a Henry Ford: you can have any color you want, as long as its black.
Nomalization standard? (Score:4, Interesting)
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.
Re:Update (Score:5, Interesting)
It looks to me like Google have done this on purpose to stop people uploading high quality audio with a still image. A lot of the music I've been listening too recently has been from youtube, I'm sure I'm not the only one...
Re:Warning from ccalam in the second video (Score:4, Interesting)
FWIW, I can hear 19 kHz waves. So this trade-off affects me.
You won't hear 19 kHz much longer. Seriously, not because of this or any other particular factor (although there are many), but because everyone experiences upper-range hearing loss as they get older, and it starts at an astonishingly early age.
Choose better. (Score:3, Interesting)
Host your video somewhere else [archive.org], upload it in a high-quality format, and let the site make derivatives for you (including a Flash video and a player you can embed in your webpage if you insist on placating a proprietor). Some organizations do this daily and it works excellently. YouTube needs you more than you need YouTube.
Teen Buzz/Mosquito Ringtone (Score:4, Interesting)
I have indeed heard of such deterioration on the Teen Buzz website (which is currently down for excessive bandwidth usage?) - but this page [wikipedia.org] describes it as well.
Those little annoying sine-wave sounds are also used by TV advertisers such as Kentucky Fried Chicken [youtube.com] 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.)
Re:Wouldn't it be easier (Score:4, Interesting)
It still matters what they do. This kind of high compression is unsuitable for most material, yet they're insisting on it. Not only does it completely kill the dynamic range - imagine going to see a classical music concert and the entire concert is played at the exact same volume, no crescendos or decrescendos - that lack of dynamic range also dramatically quickens ear fatigue. What they're doing is great if they want people to stop listening (and therefore likely watching) YouTube videos as much. Otherwise, it's a really dumb idea.
Using a noise gate to solve YouTube's poor decision is not very realistic - that's trying to get thousands and thousands of different people to fix something caused by YouTube trying to solve what wasn't really much of a problem. What's more, noise gate + high compression leads to Charlie Brown Special kinds of voice tracks and very limited musical choices - e.g., in a classical concert, instead of the quiet parts being just as loud as the loud parts, some of the quiet parts will simply be cut to silence. Noise gate + high compression can be cute for a bit in dialogue, and when done to a particular instrument - but not every instrument in a song - you can get some cool effects from it, but it's shitty thing for YouTube to require of people. It may be enough to force some users away.
reminds me of tape bias (Score:2, Interesting)
Thank the iPhone (Score:3, Interesting)
I would guess they are doing this to better "service" handheld devices like the iPhone and upcoming Android devices that have limited dynamic range in their speakers.
Re:Warning from ccalam in the second video (Score:1, Interesting)
All I can say is I'm about to turn 29, and I can still hear a TV that's on in another room to this day. High pitch whines in audio systems are easy to hear as well. Maybe mine will last a little longer since I work in the audio field listening for this stuff, and have become "trained" over time, but it's been something I've been able to do since I could remember
Re:Warning from ccalam in the second video (Score:1, Interesting)
You would think they would strip all the sub/supersonic freqs, strip out one of the channels, etc., before compressing to keep the size down..
Re:and who came up with it? (Score:4, Interesting)
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.
19KHz? Why not 1Hz? (Score:2, Interesting)
Comment removed (Score:3, Interesting)
Re:Warning from ccalam in the second video (Score:3, Interesting)
I worked with a guy once at a computer recycling place. He clearly had Asperger's, from the way his 'stories' were a list of facts delivered in a monotone, to his encyclopedic knowledge of model numbers and release years, to his inability to explain himself to anybody in charge. He could tell if a monitor was good or not by plugging it in and just hearing the tone that the transformer ( or whatever electrical component it was ) made. No need to plug it in to a video source or anything.
BTW, I downloaded all the tones at Free Mosquito Ringtones [freemosqui...gtones.org], and I was able to hear all of them, from 8 khz to 22 khz. ( Only 18 year olds or younger are supposed to be able to hear the 20+ khz ). I'm turning 30 this month; I suppose next month I won't be able to hear all of them.
Re:Update (Score:2, Interesting)
Re:and who came up with it? (Score:2, Interesting)
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 you want to boost the harmonics, improve intelligibility and make it sound richer, an Aural Exciter might be what you want. Though it might help, multi-band compression is not really intended for this. Also, as per the OP, single-band compressors are generally designed to limit the production of modulation artifacts. It's designed to boost levels, which may bring out faint harmonics, but will more likely, in the case of people's YouTube videos, boost background noise.
Of course, if I had it my way, I'd just put a flanger on everything.