[Python-Dev] linuxaudiodev test does nothing
Charles G Waldman
cgw@fnal.gov
2000年8月31日 15:59:12 -0500 (CDT)
Jeremy Hylton writes:
> >> I can play the .au file and I use a variety of other audio tools
> >> regularly. Is Peter still maintaining it or can someone else
> >> offer some assistance?
The Linux audio programming docs do clearly state:
> There are three parameters which affect quality (and memory/bandwidth requirements) of sampled audio
> data. These parameters are the following:
>> Sample format (sometimes called as number of bits)
> Number of channels (mono/stereo)
> Sampling rate (speed)
>> NOTE!
> It is important to set these parameters always in the above order. Setting speed before
> number of channels doesn't work with all devices.
linuxaudiodev.c does this:
ioctl(self->x_fd, SOUND_PCM_WRITE_RATE, &rate)
ioctl(self->x_fd, SNDCTL_DSP_SAMPLESIZE, &ssize)
ioctl(self->x_fd, SNDCTL_DSP_STEREO, &stereo)
ioctl(self->x_fd, SNDCTL_DSP_SETFMT, &audio_types[n].a_fmt)
which is exactly the reverse order of what is recommended!
Alas, even after fixing this, I *still* can't get linuxaudiodev to
play the damned .au file. It works fine for the .wav formats.
I'll continue hacking on this as time permits.