Vorbis - May 2001 - wishlist for ogg123 += Non-blocking verbose messages

Hi,

I am using the ogg123 player through an emacs interface to mpg123 I
patched up to support ogg123 (shameless plug, see
http://asf.void.at/emacs.html). This has a problem (apart from it being
emacs, which might offend some of you (-:):

The verbose output from ogg123 is collected and inserted into a
temporary buffer. This works when emacs has nothing else to do, but
fails when it blocks. Then, the stderr file descriptor is not read and
therefore, not flushed. This is, as you can see, a bad thing, because it
blocks the player and produces skips (This also is why you can also stop
the player by pressing Control-s at the console, when debugging output
is on).

I don't think that the unavailability of a file descriptor should stop
ogg123 from playing sounds. AFAICT, it is possible to use the stderr
stream in nonblocking mode, which should give ogg123 greater tolerance
to such errors. How hard is it to do that? I would really like to see
this bug (is it a bug? I think so...) fixed in ogg123.

Thanks,

-- 
Andreas Fuchs, <asf@acm.org>, <d96001@htlwrn.ac.at>, antifuchs



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> I don't think that the unavailability of a file descriptor should stop
> ogg123 from playing sounds. AFAICT, it is possible to use the stderr
> stream in nonblocking mode, which should give ogg123 greater tolerance
> to such errors. How hard is it to do that? I would really like to see
> this bug (is it a bug? I think so...) fixed in ogg123.
Non-blocking won't help, I think...  Increasing the buffer size on the
stderr stdio-stream could help, as well as removing the linemode from
stderr (which flushes on every newline).

Cheers,

Segher

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Andreas Fuchs (asf@acm.org) wrote :
> Argh, this has been sitting in my outgoing queue for quite some time 
> now... (-: 
> 
> On 2001-05-30, Kenneth Arnold <ken@arnoldnet.net> wrote: 
> > nonblocking possibly, but a simple select on fd 2 might do it (or is 
> > there a way to test if a write will block besides select?). 
> 
> Okay, this here is the hackish solution (patch to the beta4 version, but 
> I think that it ought to work with the newest CVS also): 
> 
>    text/x-patch attachment: ogg123-with-async-verbosity.patch 
> 
> 
> It only checks whether it can write without blocking when writing the 
> "\rTime: %02li:%05.2f [%02li:%05.2f] of %02li:%05.2f, Bitrate: %.1f
\r"
> message, which is kind of suboptimal. I think that it should be done 
> in a uniform way anyway, which would mean that every call to 
> fprintf (stderr...) should be replaced by a function that checks whether 
> it can write, and only then writes to stderr. 
Or you could just stop (ab)using stderr for something it was not
designed for.
 
> Oh, and BTW: this patch adds another command line switch, -a for 
> asyncronous (yes, it could also be "artifact", as it is not
really
> asyncronous I/O, AFAICT (-:). 
> 
> > If you give me a simple remote-control interface (similar to
mpg123's
> > maybe?) I could implement it, but not soon because I have tons of 
> > end-of-year concerns to worry about and I'm not getting graded on 
> > ogg123. Volunteers? 
> 
> Hm, that's next[1] on my TODO list. Right now, apt-get is pulling the 
> mpg123 source over to my computer. 
> 
> [1] Actually, it wasn't. I'll take a look at it as soon as I have 
>     time again, which should be soon. 
> 
> -- 
> Andreas Fuchs, <asf@acm.org>, <d96001@htlwrn.ac.at>, antifuchs

-- 
David Balazic
--------------
"Be excellent to each other." - Bill & Ted
- - - - - - - - - - - - - - - - - - - - - -

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