[MPlayer-dev-eng] Audio visualization

[Andrew Calkin]

>
> > Check out libvisual, and search the MPlayer m/l archives. There is
> > already plugin support for MPlayer in libvisual, apparently.
>
> As I understood, there is xmms is needed for using mplayer with
> libvisual and its xmms-plugins. If it is true, IMHO it is too
> inconvenient for lots of application and bulky.
>
> I think there is another and more powerfull approach could
> be used to add this feature to mplayer without xmms and libvisual.
> It could be implemented as additional feature which is enabled
> in command line (maybe with -viz [oscill | spectrum | ... ]) only
> if only one stream is present - audio.
>
> This feature could be useful for various diagnostic / test /
> demonstration purposes.
>
> Any advices / objections?
>
> Thank you for your consideration.

IIRC, the issue was the messing with video and audio streams. The way
it was implemented before was that the audio was output via an audio
fifo to libvisual as well as the regular output. Then libvisual
generated the required images using optimized routines and exported
those images to a fifo. The image fifo was read by -vf bmovl and used
to display the image on MPlayer vo.

IMHO I really think that reinventing the wheel in terms of re-writing
libvisual image creation algs is not such a good idea, and the
internal messing with audio/video streams would not be accepted into
MPlayer (at least that was the stance of developers some years ago,
according to m/l archives I looked at, IIRC). The export of audio and
import of the video overlay images was at least tolerated. I am not
sure how the audio export/bypass worked exactly, but surely you can
google the m/l thread from years back, as I did.

See the thread from around 2003-11-14 by Gustavo Sverzut Barbieri. I
don't think the export audio stuff was limited to xmms, a libvisual
plugin to interface exists for libvisual, which i _think_ can
interface with the exported audio fifo directly.

HTH

//Andrew