Ideas on DSP (APU audio post-processing)!

[jcee]

how abut dsps.. hopefully costumizable... not hardcoded plz

ppl could build some dsp settings with the sdk and publish them.
at runtime a gui would be nice to then set costume dsp parameters
i would love to have this option. i am very interested in (and would spend lots of time into) ...

- room simulation (reflexions, reverb)

- adjusting stereo basis

- runtime and delay adjustments (to compensate for listener not sitting exactly in the middle of all speakers)

- eq (of course) ;-)

- low and high pass filters:
*imagine having only small front speaker.. so directing the * low frequencies to the sub and only middle and high to the front speakers.

- decreasing dymamic range.
interesting for watching action movies at low volume: a sudden "bang" or explosion would not annoy your neighbours ;-) and at the same time you could hear the dialogs loud enough

- increasing dynamic range. (guess for what this is goog ;-)

and lots more.

[jmarshall]

these are good ideas, and i'm sure that at least some of them are achieveable, and i'm planning on doing some research into exactly what the xbox can do, and trying it out for myself.

one comment regarding the lowpass/highpass thing.

the xbox can only output either a pcm (2 channel) signal or a 5.1 signal. the job of lowpass/highpass should be handled by the users receiver - not by the xbox imo. otherwise you get into problems with cascading filters (ie possible bad phase effects) and the like. also, it would force the user to output in the compressed dd mode which isn't exactly optimal. i'm not sure if any benefits outway the cons.

cheers,
jonathan

[fankey]

i attempted to utilize the dsp a while back with xbmp. the basics weren't too hard. i figured out how to configure and download a dsp image and was able to cofigure some biquads into hi/low/band pass filters and adjust them in real time. unfortunately, i got horribly frustrated with trying to implement a gui within xbmp and gave up at the time.

i was planning on looking into xbmc and see if the gui stuff is at all comprehensible. if the code's been cleaned up there might be some chance of me completing at least basic functionality.

i agree that the receiver should be doing xover/delay but it might be useful to people without fancy recievers. also some effects might be fun to play around with.

if anyone's interested in working on this with me, let me know. if you want to go at it yourself, be warned that the dsp documentation at best lacking, and at worst outright incorrect! ( at least in the xdk i was using at the time )

[Gamester17]

@fankey, your feedback is wanted in the xbmp forums too http://www.xboxmediaplayer.de/cgi-bin....;t=2732 (http://www.xboxmediaplayer.de/cgi-bin/ib31/ikonboard.cgi?act=st;f=3;t=2732) http://www.xboxmediaplayer.de/forums/non-cgi/emoticons/tounge.gif

[fankey]

i replied over there. i'm going to attempt to move my work over to the new code base. if there's anyone with xbmc gui experience that would like to work with me on this please contact me - i'm sure it will speed up the process.

[Gamester17]

i'm going to attempt to move my work over to the new code base. if there's anyone with xbmc gui experience that would like to work with me on this please contact me - i'm sure it will speed up the process.
i suggest you post a new topic in the xbmc development forum with the techical but what you going to do & what you need

[fankey]

i suggest you post a new topic in the xbmc development forum with the techical but what you going to do & what you need
will do. i've already got my old stuff compiled into xbmc. i'm very impressed with the changes they made to code architecture - what took me 3 days to figure out with xbmp only took me 20 minutes with xbmc. good job guys!

on a side note, was there something wrong with the forum last night? i wasn't able to log in from home even though i could log into the xbmp forum. no error message - it just went back to the forum page without me being logged in.

[candeuterio]

Why not to use DSP for audio proccesing? Room simulation, reverb, eq, etc...

[jmarshall]

Because we don't have the time or the inclination?

Anyone who does is most welcome, and will ofcourse get whatever support they need (assuming they're competent enough).

[candeuterio]

In the era of XBMP there was a person that do a little work, but he couldn´t do the gui:

http://www.xboxmediaplayer.de/cgi-bin/ib31/ikonboard.cgi?act=ST;f=3;t=2732
http://www.xbmc.xbox-scene.com/forum/showthread.php?t=107&highlight=reverb

[pike]

we know very well.

just FYI xboxmediaplayer.de domain dies very soon, so if there's any info in that forum you need regarding the DSP code, grab it now!

[SleepyP]

why would you want to put reverb on outgoing audio from XBMC??? that strikes me as something that would only be cool for about 5 minutes and then you would say "oh wait, that's annoying, i should turn that off now".

[candeuterio]

A bit of reverb help listen music in a 5.1 system. Actually, the form used for stereo to surround in XBMC isn´t very good. Also, a equalizer help me to adjust low band because many home cinemas didn´t have it.