[maemo-developers] [maemo-developers] Audio on scratchbox and 770

[From: Danny Milosavljevic]

Hi,

Am Donnerstag, den 02.02.2006, 12:42 +0200 schrieb Teemu Nikkilä:
> Hi all,
> 
> I've been trying to understand the audio (and multimedia) framework on the 
> 770, but with not much success. There seems to be a shortage on documentation 
> on this subject, or maybe I just don't know how to find it.
> 
> So this far I've managed to figure out that on the 770 the multimedia stuff is 
> built on gstreamer (GST) and esound (ESD) and that you can use SDL for low 
> level access to audio and video output [1]. 


> I've also tried to write 
> to /dev/dsp on  scratchbox, which works just fine, so I'm led to believe that 
> scratchbox is OSS enabled.

nice :)

> 
> The problems I've encountered so far are: ESD unfortunately refuses to start 
> on scratchbox because of missing /dev/dsptask/pcm1. And 770 OTOH is missing 

> esddsp, which I believe could be used as a wrapper to allow all those 
> applications, who use /dev/dsp, to work without modifications. 

overkill?

> Also missing 
> on 770 are some gst-utilities like gst-inspect and gst-launch.

And the video player can't stream non-real-video formats (at least we
don't find one that works ;))

(*looks at nokia* :))

> 
> So my questions (for now) are: 
> could someone, who knows the multimedia system well, write a small (or maybe 
> even comprehensive) howto or a tutorial on the subject to Maemo Wiki?
> 
> What is osso-media-server?
> 

> Is using libSDL really the best way to write sound related applicatons for 770 
> (like is done with OggPlay)? 

> For me it looks like a work-around, unless you 
> are into games development, 

Well, at least it isn't a full-blown mixer daemon a la esound.
And if
- SDL is on the device either way
- OSS is supported as well
using SDL for sound is fine, and you could still use OSS (/ALSA?)
directly


> while using ESD or GST directly would be the 
> right thing(tm) to do.
> 

> How about making scratchbox 770 compatible in respect to ESD? Is this 
> difficult to do yourself? This would make development and testing easier.

I don't understand why esound is still around at all (even on desktops).
What good does it do?

cheers,
  Danny