See messages below.
Should I be upgrading from rc2 to rc5 or is this unlikely to help with
ice1712 ?
One furthur thing I've tried is putting my IO code in a seperate thread
and running in/out
to the soundcard continueously (outputting silence when I don't want
anything). A desperate
solution that also unfortunately still results in distorted sound after
a period of time
(but no under/over runs reported). The distortion is different in nature
doing it this way
(more a warble), but it's still there.
As far as I can tell I am fully complying with the alsa API.
Bruce Paterson wrote:
>
> Bruce Paterson wrote:
> >
>
> I got zero feedback on the problem below, so I thought I'd add the code
> segment and see
> if anyone can tell me what I'm doing wrong !
> See code below.
>
> > HELP !
> > I've tried everything I can think of and I'm at a loss.
> >
> > Setup:
> > alsa 0.9.0rc2
> > soundcard Terratec EWS88 (ice1712 driver)
> > direct hw:0,0 using snd_pcm_readi & writei with descriptor polling.
> > length approx 50s similtaneous read & write. read from all channels.
> > modified 'envy24setup' to preset hardware levels on startup
> > full restart of sound system each 'pass' (new handles etc.)
> >
> > Problem:
> > The first pass works fine with beautiful audio.
> > The next pass the output is badly distorted (sounds like an incomplete
> > buffer or something), but
> > no errors reported, no under/overruns.... only evidence that something
> > is wrong is to listen to it.
> >
> > What fixes it:
> > Waiting. Yup...if I wait > 1 minute before the 2nd pass then that is
> > also fine. Something 'happens'
> > in that time to make it all ok again.
> > This is why it's taken me ages to actually notice the problem at all !
> > (program has been running
> > for months).
> >
> > What *doesn't* help:
> > Not doing a full sound restart between passes (ie. merely doing a drop
> > afterwards, then restart with
> > prepare & start, leaving pcm handles alive).
> > Playing a wav file with 'aplay' in between passes.
> > Exiting from my program and starting again between passes.
> > adding hw_free commands prior to close of the in & out handles.
> Here is the code segment in question. The periodsize is setup to be 1/4
> of the buffersize which is set
> to the maximum the soundcard will give me. When restarting the soundcard
> is initialised from scratch
> (new fd's), but I tried without doing this and it makes no difference):
>
> /* Get one full width buffer, buffersize is in frames. */
> outbuf = (char *)calloc(out_buffer_size * OUTCH,
> snd_pcm_format_width(format) / 8);
> /* calloc since we want silence initially on output */
> inbuf = (char *)calloc(in_buffer_size * INCH,
> snd_pcm_format_width(format) / 8);
>
> /* Start the ball rolling */
> snd_pcm_prepare(outhand);
> snd_pcm_prepare(inhand);
> snd_pcm_reset(outhand);
> snd_pcm_reset(inhand);
> snd_pcm_start(inhand);
>
> /* This is the IO loop */
> outp = a buffer that contains what I want to output;
> outl = length of said buffer;
> outs = (QUIET * (Fs/1000)); /* Pre-silence output time */
> Delay *= Fs; /* Change to sample count */
> Delay += QUIET * (Fs/1000); /* Always delay the output quiet period as
> well */
> dc = Delay;
> samps = N;
> ocopy = 0;
> /* inptrs already point to fmptrs */
> for(;;)
> {
> if(outs)
> out = outs;
> else
> {
> if(outl)
> {
> if( ocopy == 0 )
> {
> ocopy = 1;
> /* Copy from single channel full buffer to
>full width one */
> sampl = (long *)outp;
> sampm = (long *)outbuf;
>
> for(x=0; x < out_buffer_size; x++)
> {
> /* only 2 channels output (180 deg
>out of phase) */
> *sampm = *sampl++;
> sampm += OUTCH; /* Skip
>over other output channels */
> if( x > outl )
> break;
> }
> out = outl;
> }
> }
> else
> out = out_buffer_size; /* Silence after */
> }
>
> /* See if ready for output data yet */
> poll(outfds, ocount, -1);
> snd_pcm_poll_descriptors_revents(outhand, outfds, ocount,
> &revents);
> if (revents & POLLERR)
> {
> fprintf(stderr, "Tx Poll failed\n");
> err = -1;
> break;
> }
> if (revents & POLLOUT)
> {
> err = snd_pcm_writei(outhand, (void *)outbuf, out >
>out_buffer_size ?
> out_buffer_size : out );
> if( err < 0 )
> {
> /* EAGAIN Shouldn't happen now since we're polling
>first */
> if( err != -EAGAIN )
> {
> fprintf(stderr, "Write failed %s",
>snd_strerror(err));
> break;
> }
> }
> else
> {
> if(outs)
> outs -= err;
> else
> {
> if(outl)
> {
> outl -= err;
> outp += err *
>snd_pcm_format_width(format)/8;
> ocopy = 0;
> if( outl == 0 )
> {
> /* Finished actual output.
>Now fill buffer with silence again */
> sampm = (long *)outbuf;
> for(x=0; x <
>out_buffer_size; x++)
> {
> *sampm++ = 0;
> *sampm = 0;
> sampm += OUTCH-1; /*
>Skip over other output channels */
> }
> }
> }
> }
> }
> }
>
> /* See if data ready to be read yet... we started sampling earlier.
>*/
> poll(infds, icount, -1);
> snd_pcm_poll_descriptors_revents(inhand, infds, icount,
> &revents);
> if (revents & POLLERR)
> {
> fprintf(stderr, "Rx Poll failed\n");
> err = -1;
> break;
> }
> if( !((revents & POLLIN) || (revents & POLLPRI)) )
> continue;
>
> if(dc)
> {
> err = snd_pcm_readi(inhand, inbuf, dc > in_buffer_size ?
> in_buffer_size : dc);
> if(err < 0)
> {
> if( err != -EAGAIN )
> {
> fprintf(stderr,"Read error at %ld: %s\n",
>Delay-dc,
> snd_strerror(err));
> break;
> }
> }
> else
> {
> dc -= err;
> if( dc )
> continue;
> }
> }
>
> /* Finally actually record some real stuff */
> err = snd_pcm_readi(inhand, inbuf, samps > in_buffer_size ?
> in_buffer_size : samps);
> if(err < 0)
> {
> if( err != -EAGAIN )
> {
> /* No point in underrun recovery in this application
>so abort */
> fprintf(stderr,"Read error at %ld: %s\n", N-samps,
> snd_strerror(err));
> break;
> }
> }
> else
> {
> samps -= err;
> /* Copy from full width buffer to channels */
> for(y=0; y < channels; y++)
> {
> sampl = (long *)inbuf + y;
> sampm = (long *)inptrs[y];
> for(x=0; x < err; x++)
> {
> *sampm++ = *sampl;
> sampl += INCH;
> }
> inptrs[y] += err * snd_pcm_format_width(format)/8;
> }
> if( samps <= 0 )
> break;
> }
> }
> fprintf(stderr,"Sampling Completed\n");
> snd_pcm_unlink(outhand);
> snd_pcm_drop(outhand);
> snd_pcm_drop(inhand);
> snd_pcm_hw_free(outhand);
> snd_pcm_close(outhand);
> snd_pcm_hw_free(inhand);
> snd_pcm_close(inhand);
>
> /* Free up temporary memory */
> free(inbuf); free(outbuf);
>
> --
> Cheers,
> Bruce
> -------------------------------------------------------------------
> This email and any files transmitted with it are confidential and
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> /\\\/\\\/\\\ / / Bruce Paterson
> / \\\ \\\ \\\ / / Senior Design Engineer
> / /\\\/\\\/\\\/ / 87 Peters Ave, Mulgrave, Vic, 3170
> / / \\\ \\\ \\\ / PO Box 4112, Mulgrave, Vic, 3170, Australia
> / / \\\/\\\ \\\/ Ph: +61 3 8561 4232 Fax: +61 3 9560 9055
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--
Cheers,
Bruce
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/\\\/\\\/\\\ / / Bruce Paterson
/ \\\ \\\ \\\ / / Senior Design Engineer
/ /\\\/\\\/\\\/ / 87 Peters Ave, Mulgrave, Vic, 3170
/ / \\\ \\\ \\\ / PO Box 4112, Mulgrave, Vic, 3170, Australia
/ / \\\/\\\ \\\/ Ph: +61 3 8561 4232 Fax: +61 3 9560 9055
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