patch: simple recording with artsdsp

Stefan Westerfeld stefan at
Sun Feb 9 23:01:58 GMT 2003


On Fri, Jan 24, 2003 at 01:53:53PM +0100, Simon Hausmann wrote:
> the attached patch implements primitive recording capabilities with
> artsdsp. It makes it possible to use Teamspeak with arts. I have not
> tested recording capabilities with any other applications, which is
> why I said 'primitive support' , it works perfect with ts though.
> [... patch ...]

As far as I can see, the patch you wrote does add some recording abilities
to artsdsp cleanly, so its good you committed it now. There are a few cases
of recording that are supported now and a few that still are not.

 - application opens /dev/dsp once for reading data from it
 - application opens /dev/dsp once (with one fd), for reading and writing,
   and starts reading/writing data to it

still unsupported:
 - application opens /dev/dsp twice (two different fds), eventually with
   different settings for sampling rate and bit depth, and starts reading
   and writing data via those two file descriptors

   => result with your patch applied: doesn't work, as you have only variable
   for sndfd, audio parameters, ...
   => suggested fix: rewrite artsdsp to maintain a list of sound fds, which
   also fixes opening twice for writing in one application

 - application uses mmap to record data

   => result with your patch applied: doesn't work, as your patch does not
   bother about artsdsp -m
   => suggested fix: bother about artsdsp -m for recording streams

 - application uses select to find out when to record data

   => result with your patch applied: doesn't work, as artsdsp doesn't do
   anything with the select() and poll() system calls
   => suggested fix: do something with select() and poll() in artsdsp

So for the ideal solution, these outstanding issues need to be fixed in
artsdsp. However, thats not an argument against having the patch applied,
as without it, the list of outstanding issues would be even longer. ;)

   Cu... Stefan
  -* Stefan Westerfeld, stefan at (PGP!), Hamburg/Germany
     KDE Developer, project infos at *-         

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