[vdr] For LiveAC3: new ac3play version

["Dr. Werner Fink" <werner@suse.de>]

Hi,

     I've done some work on an ac3play version which is now
fully synchrony it used with VDR together with the LiveAC3
patch (included in Andreas Schultz DVD/nav patch).
The URL of the RPM is

    http://www.alsa-project.org/~iwai/ac3play-0.5.2f-0.i686.rpm

and the source tarball can be found at

    http://www.alsa-project.org/~iwai/ac3play-0.5.2f.tar.bz2

Before trying out this version you may read the manual page.
E.g. my onboard sound chip is able to use mmap and provides
its raw playback PCM device at /proc/asound/card0/pcm2p/.
Therefore I'm using a script with the -a option of VDR

    /usr/lib/vdr/ac3play.sh

with the contents

   #!/bin/bash
   exec -a ac3play ac3play -m -P ${1+"$@"}

(don't forget to run `chmod 0755 /usr/lib/vdr/ac3play.sh' if
you want to use this way:)

Short description of the changes:

     I'm using three states in this ac3play version depending
     on the fill grade of the hardware buffer of the sound
     chip : LOW, OK, HIGH ...

     In LOW state the read date from VDR will be parsed and
     given out to the alsa interface as fast as possible
     (no delay from holding data within the buffer) and it
     will be always checked if new data is arrived from the VDR
     pipe.  If not the alsa interface will be drained and 
     prepared for a restart.

     In OK state a buffer is fully used for transferring data
     to the alsa interface.  The same hold true for the HIGH state
     but in HIGH state this ac3play version wait on the alsa interface
     to be become OK state again.



             Werner