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#127763 - 25/11/2002 08:59 SAM on pause -- why? (Attn: empeg guys)
tonyc
carpal tunnel

Registered: 27/06/1999
Posts: 7058
Loc: Pittsburgh, PA
As chronicled in this thread, progress has been impressive in the effort to bring quasi-realtime text-to-speech to the empeg. Seeing this, I tried to raise Kim Salo's audio overlay patch from the dead, so that user apps can speak and/or play sounds while the player is playing. That works pretty well, except when the player is paused.

It turns out that the player sets Soft Audio Mute when it's paused. This is a problem if we want to have user apps that want to output audio while the player is paused. For a stopgap solution, I have the SAM ioctl dummied out so it doesn't actually set SAM on the DSP. Not sure this is a good solution for the long-term though.

So maybe you guys can enlighten me... What is the need to set soft audio mute when the player is paused? If you're not outputting any sound from the player app, isn't that as good as muting? It seems to me setting SAM is superfluous, and interferes with a user app's ability to send PCM sounds when the player is paused. Unless there's a pressing need for it, I'd like to see the SAM ioctl call removed for a future release. If we want a true "mute all sounds, even user app sounds" function, we can add that later.. But I can think of a lot of cases where user apps would want to play sounds while the player is paused, particularly if we start having talking menus, or have GPSapp announce turn-by-turn directions.

So, any thoughts?
_________________________
- Tony C
my empeg stuff

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#127764 - 25/11/2002 11:34 Re: SAM on pause -- why? (Attn: empeg guys) [Re: tonyc]
altman
carpal tunnel

Registered: 19/05/1999
Posts: 3457
Loc: Palo Alto, CA
It was there because I believe the SAM hardware mute in the DSP is quieter than simple "data is zero" mute. This gives a cleaner pause.

The difference is probably minimal, though, and I might be completely wrong - it was a long time ago!

Hugo

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