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2005, Dec 03

Environmental Audio

Filed under: Uncategorized — Hrishikesh @ 19:53

My PC has a decent 5.1 channel Creative manufactured speaker and sound-card solution. Which basically makes movie and even normal TV watching a very rewarding experience.
 
The thing is, the sound card does some very fundu stuff: When the video has scenes of a hall, or a similar closed room, the output actually changes to provide the reverb and the echo. Ditto for scenes in closed quarters, such as a bathroom, or songs that have what they call ambient sounds (in the high frequency range, that provides the feeling of space).
 
All of which is top class, makes for an awesome session.
 
But my question is: Where does this information come from? AFAIK, the conventional DivX / Xvid encoded audio has a 2 channel stream (or in some cases, 5), which carries zero environment data. DVDs may carry it, but recorded TV programs surely don’t. And yet, when I play back the media in VLC Player, it sounds freakingly kewl. Now, games that support the EAX standard can do all of that, and that’s fine too, because I know that the game developer put additional information about how the sound should, well, sound… Including equalizer settings, environments, reverb, chorus, echo and so on.
 
So does the VLC Player have some sort of algorithm that deciphers some hidden frequency patterns in the recorded sound, and enables the stuff on the sound card, or what? And if this is possible, why doesn’t every one do it?
 
I really need to read up on this somewhere… Links, explanations and chat welcome!

  • http://www.blogger.com/profile/5118250 Nadeem Mohsin

    For what it’s worth, I just started using VLC player – and it’s incredible! Thumbs up to the headphone virtualization mode. Now I can don my headphones and enjoy a credible simulation of a 5.1 speaker set.

    Haven’t tried it on videos yet. Will give it a try right now.

  • http://www.blogger.com/profile/5118250 Nadeem Mohsin

    For what it’s worth, I just started using VLC player – and it’s incredible! Thumbs up to the headphone virtualization mode. Now I can don my headphones and enjoy a credible simulation of a 5.1 speaker set.

    Haven’t tried it on videos yet. Will give it a try right now.

  • http://www.blogger.com/profile/5154159 rohit bhute

    Me thinks you should praise your sound system. AFAIK, it simply decides the channel for each sound based on its frequency, or some similar parameter. Like, take a human screaming at the top its pitch. It will give different values on a frequency meter if you try it on a hill, in a hall or in a bathroom. I guess your soundcard hardware and software do a fine job of splitting and touching things up.

    Here’s something for you to try. Wimamp has a cool DSP plugin. Where you do stuff you learnt in DSP-I and DSP-II – sin, cos, fourier, delay, etc. Try it out and see how your system plays the sound. You might get to the root of things.

  • http://www.blogger.com/profile/5154159 rohit bhute

    Me thinks you should praise your sound system. AFAIK, it simply decides the channel for each sound based on its frequency, or some similar parameter. Like, take a human screaming at the top its pitch. It will give different values on a frequency meter if you try it on a hill, in a hall or in a bathroom. I guess your soundcard hardware and software do a fine job of splitting and touching things up.

    Here’s something for you to try. Wimamp has a cool DSP plugin. Where you do stuff you learnt in DSP-I and DSP-II – sin, cos, fourier, delay, etc. Try it out and see how your system plays the sound. You might get to the root of things.

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