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Unbehagen · 2007-10-11, 19:38

Hi,
I'll have a hands-on course on audio filters at university next semester. Now my idea is to create something useful as the course's homework. I'll try to convince the prof that it would be a very nice thing to code these things for an open source project like XBMC. I would do this together with a friend of mine who is a genius in audio stuff. Before asking the prof about this, I'd like to know a few things:

does anyone know a lot about how audio in xbmc works who could help me a bit with this and tell me where i should integrate the equalizer and filters
do I have to code this seperately for each of the player cores or is there a central output that I could grab that all of xbmc's audio output is directed through?
did anybody ever start coding such a thing?
i find it pretty weird that the equalizer feature is still missing - why did nobody code this yet? Is there something I didn't see yet that makes this unbelievably hard?

Thanks for your answers!

**pike** · 2007-10-11, 20:06

reason it's missing is because our "In house" devs don't think it's a useful feature.

back in xbmp days a guy began work on a DSP based EQ, the nvidia chipset in the xbox has a DSP that is virtually unused today by XBMC. Drawback of this approach would be that it would be a Xbox unique feature.

Prime concern of mine would be to take care of quality (as much as one can do with an EQ) for instance, never go + on any band, instead lower the other bands accordinly so to avoid clipping.

for the other questions I hope a developer can offer assistance

Unbehagen · 2007-10-12, 00:49

any other audio filter related stuff you would like to have accomplished?

**pike** · 2007-10-12, 02:23

nothing I can think of right now but I will ponder it. If I think of something I will post in this thread

Rudepooch · 2007-11-16, 07:25

Hey,

I was just wondering if you would be interested in doing something about the delay in mic audio in xbmc Karaoke. there is a brief delay between when you sing and as a result your singing (in the speakers) is always out of sync with the music.

jmarshall · 2007-11-16, 10:30

It's as low as possible to my knowledge. The official xbox karaoke program probably does the same thing.

Gamester17 · 2007-11-16, 13:16

pike Wrote:back in xbmp days a guy began work on a DSP based EQ, the nvidia chipset in the xbox has a DSP that is virtually unused today by XBMC. Drawback of this approach would be that it would be a Xbox unique feature.

FYI, that source code can be found here => http://sourceforge.net/tracker/index.php...tid=581841
http://sourceforge.net/tracker/download....aid=877503

dailydisco · 2007-12-27, 07:42

jmarshall Wrote:It's as low as possible to my knowledge. The official xbox karaoke program probably does the same thing.

Actually, we used Media Mixer (the official karaoke program) quite a bit as my wife really liked the karaoke and DDR aspects of the Xbox... we used to have parties with friends and record the performances (one of the cool features of the program). The interface was terrible, though, and the rest of the media mixer generally sucked. BUT...

The delay in the karaoke of the official media mixer was nowhere near as bad as it is in the XBMC implementation... it gets much worse when the "filters" are applied.. it actually becomes challenging to sing since the delay messes with your head so much. I don't know what trickery they used, but improvements to the karaoke feature would be much appreciated... it doesn't get much play in the forums and some developers probably don't like karaoke, but when I discovered this in XBMC I was pretty happy... anything that makes my wife happy is a good thing! Incorporate an updated "Step Mania" and well...

Gamester17 · 2007-12-27, 16:55

I have also tried the "Xbox Music Mixer" (WildTangent made, but produced by Microsoft) , and also "Karaoke Revolution" and "Karaoke Revolution Party" (for the original Xbox by Konami) and none of those did too me nor my ex-girlfriend and firends have any noticable delay so it must be technically possible to reduce the delay more by some kind of other method than currently used in XBMC.

I have to agree with dailydisco that girlfirends/wifes and their firends really love karaoke, ...so any such features really helps when 'selling' the idea of XBMC to woman, (my ex-girlfirend also had a dancemat and StepMania to my Xbox which also helped even more, all my friends wanted Xbox and it is not hard for them to convince their girlfirends/wifes to let them buy one when they see the Xbox karaoke and dacemat in action at parties).

bob.smith · 2007-12-28, 13:41

i got an xbox music mixer from santa, and the wife (and the three year old) love it.

However, they love the xbmc karaoke more than the music mixer because i can play all the CD+G discs i have from my wedding/party Dj days, so they have more music choice.

The delay when singing is quite long, and as others have stated the official software doesn't suffer in the same way, so we can rule out the hardware, that leaves the XBMC audio implementation.

Having said that, i fired up the VC+XDK and stepped my way through the karaoke audio, i was left bewildered. So i fired up some of the XDK audio samples, and i have started to work through those, because i'm confused about the different inputs and output channels and how they are mixed.

I think it will take a fair amount of work to sort out the delay, because i don't think its intentional, i think the passing of packets is possibly introducing the delay.

I know all the dev effort is currently concentrating on high impact bug fixes and the port to Linux, so i'm guessing this fix would rank pretty low on team XBMC priority list.

I will gladly help with improving the karaoke feature, as i believe it is an important string to the XBMC bow, and feature that should be given a little more exposure.

BOB.SMITH

Gamester17 · 2007-12-28, 16:24

bob.smith Wrote:I know all the dev effort is currently concentrating on high impact bug fixes and the port to Linux, so i'm guessing this fix would rank pretty low on team XBMC priority list.

True, and also as far as I know no one of the developers on Team-XBMC is actually personally interested in karaoke (and that is why the quality of that feature in XBMC has suffered), ...you see since no one working on XBMC gets paid eveyone tend the only/mostly work on the features that interest them personally.

bob.smith Wrote:I will gladly help with improving the karaoke feature, as i believe it is an important string to the XBMC bow, and feature that should be given a little more exposure.

Thank you! All of use who can not code to save our lifes but like to see the karaoke features in XBMC get better really appriciate any improvements/enhancements made to it.
http://xboxmediacenter.com/wiki/Development_Notes
http://xboxmediacenter.com/wiki/HOW-TO_submit_a_patch

FYI; here is the audio processing chain/path of XBMC illustated:
http://xbmc.svn.sourceforge.net/viewvc/x...iew=markup

Maybe you will need to create an entirely new audio process path for the microphone(?) Big Grin

bob.smith · 2008-01-12, 12:42

hmm the octopus is well and truly out of the string bag Sad

BOB.SMITH

**pike** · 2008-05-19, 13:58

any progress update on this Unbehagen ?

bob.smith · 2008-05-20, 00:52

sorry Pike,

i'm very busy trying to sell my house right now, all my kit is in storage.

Also i'm not sure what the bigger picture is with regards to the life of XBMC once it is on a stable release for linux. Is there a product roadmap?

BOB.SMITH