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From: tom@dbservice.com
To: Colin Guthrie <gmane@colin.guthr.ie>
Cc: pulseaudio-discuss@mail.0pointer.de, alsa-devel@alsa-project.org
Subject: Re: alsa pulse bugs
Date: Mon, 05 May 2008 12:22:10 +0200	[thread overview]
Message-ID: <20080505122210.sbwpuulog00cos4c@dbservice.com> (raw)
In-Reply-To: <fvmktt$ofl$1@ger.gmane.org>

Quoting Colin Guthrie <gmane@colin.guthr.ie>:
> Actually just having a very quick glance at the Alsa API docs, it
> doesn't mention that this value should be 0 if there are no samples to play:
>
> http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m.html#ga0d9e14a4be65209eb549e48a9f07302
>
> Closest it says is: "It's positive and less than buffer size in normal
> situation".
>
> So perhaps this is an invalid assumption at the wine side?

However this part:

Delay is distance between current application frame position and sound  
frame position.

suggests that it indeed can be zero. Or why would a soundcard have a  
gap between the read and write positions if it has played everything?

If Wine uses a wrong assumption, then please clarify the function description.

> Is there perhaps a more appropriate API call they can use to do whatever
> test they are doing?

What Wine needs to know, is whether a particular sample has already  
been played or not. It does 'bytes_written - delay_in_bytes' to find  
out how much of the written data the soundcard has already played. If  
there is a better test for it, please explain.

tom

  reply	other threads:[~2008-05-05 10:22 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20080505103410.zv8dezd9z44cksoc@dbservice.com>
2008-05-05  8:58 ` alsa pulse bugs Colin Guthrie
2008-05-05  9:11   ` tom
2008-05-05  9:18     ` Colin Guthrie
2008-05-05  9:37       ` tom
2008-05-05  9:44       ` Colin Guthrie
2008-05-05 10:22         ` tom [this message]
2008-05-05 10:31           ` Colin Guthrie
2008-05-06 19:38   ` [pulseaudio-discuss] " Lennart Poettering
     [not found] ` <20080506193616.GB25436@tango.0pointer.de>
2008-05-07  1:45   ` Colin Guthrie

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