[vlc-devel] Binaural virtual acoustics via headphones

Jean-Baptiste Kempf jb at videolan.org
Sun May 15 11:20:50 CEST 2011

On Sun, May 15, 2011 at 10:08:40AM +0200, Piotr Majdak wrote :
> >http://git.videolan.org/?p=vlc.git;a=blob;f=modules/audio_filter/channel_mixer/headphone.c;hb=HEAD
> Thanks for the pointer. It seems like there is just a delay-and-gain
> implemented. I think that this a good point to start.

Good point for start, but maybe, copy it to another file if you want to
moodify heavily.

> >seem to show 3 options, one integer (dim) and 2 booleans (one of which
> >I think is useless
> How do I use/set these options? Are these command line parameters?

As all VLC option both in command-line --option=value and in the
preferences (All->Audio->Filters->Headphones)

> >Audio filters would be welcome, and not only HRTF, but upmixing or
> >SRS-WoW-like filters
> >
> >See
> >http://wiki.videolan.org/Documentation:Hacker%27s_Guide/Audio_Filters
> >and
> >http://wiki.videolan.org/Documentation:Hacker%27s_Guide
> Thanks for the guides. I'd like to focus on HRTF implementation
> first. Maybe we'll look later how SRS-WoW actually works.

> Another general question: I'd like to adapt the filtering to the
> actual head position/orientation in real time. I thought about
> capturing the head information with web-cam using openCV or similar
> - is time-variant filtering possible within the current audio-filter
> framework?

No, it isn't now. You need to work both on the video filter and on an
audio filter.

The best might be to do the audio filter and have a callback on the
"head-angle" variable. Make a UI to change this in real-time.
Once this works, and is accepted in VLC trunk, make a video-filter that
changes that variable.

> As for the human resources, a student could work on that
> in his master thesis, so spending let's say 4 to 6 months. Do you
> think is this practicable?

Yes. Just remember that VLC is a fast evolving community... If your code
forks/evolves too far/too long from the tree, it won't get merged.
I would then recommend to merge your code as soon it is mergeable, not
when it is perfect...

Best Regards,

Jean-Baptiste Kempf
http://www.jbkempf.com/ - +33 672 704 734
Sent from my Electronic Device

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