Re: user soundmodem problems on Inspiron 8200 i810 chipset...

From: bcdefgj.atgxdjxrit@fmctc.net
Date: Thu Mar 11 2004 - 01:41:11 EET

  • Next message: Braddock Gaskill: "Re: APRS library?"

    On Wed, Mar 10, 2004 at 01:56:16PM -0800, Dave Platt wrote:
    > cat /proc/asound/card0/pcm0c/sub0/hw_params
    >
    > If you can grab, and then post the results of this
    > for the SOX and soundmodem situations, it might give

    What a great little /proc tidbit.

    After looking at the hw_params stuff, I slightly modified my sox line
    to capture 16-bit samples instead of 8-bit to better match soundmodem
    (which captures in 16-bit).

    sox -V -w -r 9600 -t ossdsp /dev/dsp -t wav -w -u -r 9600 /tmp/output6.wav

    I recorded some APRS activity with this, then verified that soundmodem
    in "file" mode would copy it from the captured wave file. Worked
    fine, I didn't see our anomaly. I captured the /proc/../hw_params
    data from this sox call, and from soundmodem (without my
    sample rate hack), which showed the anomaly.

    The period/frame parameters vary by an order of magnitude between
    them. I don't know how to change these in sox, so I can't give a
    better match (I'd LOVE to be able to reproduce the anomaly in sox so
    we could file a reproducable bug report with the ALSA folks).

    Here is /proc/../hw_params for the SOX call:
    access: RW_INTERLEAVED
    format: S16_LE
    subformat: STD
    channels: 2
    rate: 48000 (48000/1)
    period_size: 5115
    buffer_size: 10230
    tick_time: 10000
    OSS format: S16_LE
    OSS channels: 1
    OSS rate: 9600
    OSS period bytes: 2048
    OSS periods: 2
    OSS period frames: 5115

    Here is /proc/../hw_params for soundmodemconfig in 1200 bps afsk scope mode:
    access: RW_INTERLEAVED
    format: S16_LE
    subformat: STD
    channels: 2
    rate: 48000 (48000/1)
    period_size: 639
    buffer_size: 10224
    tick_time: 10000
    OSS format: S16_LE
    OSS channels: 1
    OSS rate: 9600
    OSS period bytes: 256
    OSS periods: 16
    OSS period frames: 639

    So, if someone tells me how to modify the period and buffer sizes in
    soundmodem, I'll experiment and see if I can make the problem go away.

            -braddock

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