Re: [xine-devel] Audio upmix plugin.

[Michael R. <mr...@us...>]

Hi Miguel,

> > If that does happen, there is a bug in the implementation of status() in
> > ao_port1, because status() receives a stream and should only return true,
> > when the port has been opened by that stream. (The commentaries for
> > status() in audio_out.h and video_out.h reflect that.)
>
> ok, i didn't noticed that. in that case it should work, although we
> must take care of maintaining the stream values consistent for all
> post plugins.
>
> what if i first rewire post into stream1
> 1) stream1 -> audio_post -> ao_port1
>
> and then rewire it to ao_port2 and no input (in two steps).
> 2) stream1 -> ao_port1
>
> that is, ao_port1 is opened and audio_post closed. is it safe? won't
> audio_post try to close ao_port1? remember audio_post still has its
> output wired to the same ao_port1.

When stream1 closes audio_post, it also closes ao_port1 and then, because of 
the rewire, will reopen ao_port1 using the values it opened audio_post with.
Because audio_post is closed now, its stream is set to NULL.

> 3) audio_post -> ao_port2
>
> so audio_post won't neither try to close previous port (ao_port1)
> because status will return false for stream "none", nor open the
> ao_port2. right?

Right. Since ao_port1 is not opened for the NULL stream (no port is), 
audio_post rewiring does not open or close anything. Result: audio_post and 
ao_port2 are not opened, ao_port1 is opened once by stream1. So it should 
work unless we forgot something.

> > Our current implementation of the status() functions is wrong here,
> > because the NULL value for the stream has two meanings:
> > * no stream => status() should fail
> > * an anonymous stream => status() should succeed
> > I think an engine global define for an anonymous stream would be a good
> > solution. What do you think?
>
> sounds good.

I will implement this on Friday. (Maybe even tomorrow, but Friday is more 
likely.)

Michael

-- 
/* Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
 * way.
 */
	2.4.3 linux/net/core/netfilter.c