[vorbis-dev] esd bug in ogg123

[David A. Gatwood]

I've run into two problems with ogg123 that appears only when using the
esound driver.

Case 1: pops in output

        Audible pops, especially at low volume.  Original mp3 file does
        not exhibit these pops, nor does oss output from ogg123, nor does
        esd output from mpg123.

    Things ruled out:

        disk speed - the HD is ATA/33 with DMA on.  It's a single user
            machine, and I've tried the "stress test" in the man page,
            which doesn't make the output any worse.

        message passing overhead - the message passing is nowhere near
            sufficient to cause problems on a machine with this much
            horsepower (PowerPC G4/450).  Further, running several esd
            streams concurrently makes no substantial difference (other
            than adding a little flanging from being off a msec or two
            ;-).

        esound - these problems only occur with output from ogg123,
            not from other programs (mpg123, for example) with effectively
            the same sound sample.

Case 2: sample rate "ramp-up"

        First second starts at too low a data rate and corrects over about
        a half second's time, resulting in the pitch ramping up to the
        right pitch.  Only occurs with esd.  Does not occur with mpg123 on
        original mp3 file.  Does not occur when using oss mode.  Is not
        random, i.e. if it occurs once with a given .ogg file, it will
        always occur with that file (but goes away if you switch to using
        oss mode instead of esd).

Any idea how to track this down?  Again, it has all the signs of being a
bug in the esd plugin code, but that looks so straightforward, I can't see
how it could be... unless there's some stream option for esd related to
buffering that should have been set, but wasn't.  Thoughts?

Later,
David

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