[MPlayer-dev-eng] Audio plugins

[Anders Johansson]

Hi,

> > I have been thinking of the audio out and how to configure the sound
> > card and selecting audio plugins depending on format of the audio
> > stream and the capabilities of the audio device.
> > 
> > I would like to extend the interface to the ao drivers with a new
> > function called get_capabilities() or something like that. This
> 
> why isn't control() enough?
> i really don't like API changes when avoidable...

It will do fine, I'll use control().

> > function would return a struct containing the limitations of the sound
> > card. This information could then be used to select the correct audio
> > decoder and audio plugins in order to maximize the sound quality and
> > make stuff work automaticly. The scheme would be combined with manual
> > override. It would also require some changes in the audio plugins or
> > the audio decoders and in mplayer (to get automatic hw ac3 and mpeg
> > decoding) if we want everything to auto configure.
> > 
> > Is this a good idea? Please give me your thoughts.
> good idea. anyway we shouldn't make it too auto. i mean, don't enable hw
> decoding unless user specified it in config file (like hw_audio=auto|yes|no)
> as it's very problematic at the momemt. the ac3 passthrough is a big hack,
> sending ac3 packets hidden in lpcm packets handled like le16 pcm played at
> volume 100%... i don't think it's easily detectable if the card can do taht,
> and anyway even if the card has sp/dif mayeb the user has analog system...

There needs to be a similair switch for number of speakers connected. 
I will also make a switch for enabeling and disabling autoconfig altogether.

> anyway the volume setting plugin is a good idea, someone should implement
> it. then we could move mixer code to libao drivers, and if they report 'no
> mixer support' we can automagically enable software volume control.

I will have a look at it when I implement the auto stuff. It would be
good if the mixer code could be moved before I start, who to do it?

> A'rpi / Astral & ESP-team

//Anders