"Auto Sample Rate Compensation"

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"Auto Sample Rate Compensation"

Pierre Thibaudeau
Hi there,

From time to time (no clear way to systematically produce the problem),
the received audio stops in Qtel (while the "RX" indicator is still
green). I have found that momentarily hitting the PTT makes the audio
restart. When it starts behaving like this, I usually have to hit the PTT
every 5-10 sec until the end of the ongoing reception.

This is a problem that I have seen with EchoLink and that I have
successfully worked around using a feature they call "Auto Sample Rate
Compensation". Herebelow is what the documentation says about.

It just happens that I am plagued with a sound card that has the problem
described in this documentation, so I was wondering if we could eventually
get a similar feature in Qtel.


    Auto Sample Rate Compensation:

    Check this box to allow EchoLink to compensate automatically for
    variations among sound cards. Some sound cards may operate as much as
    2% away from the desired sample rate, which can cause periodic gaps in
    received audio, even over a perfect Internet connection. When this
    feature is enabled, EchoLink detects this problem and inserts or
    removes packets to compensate for it dynamically. You might perceive
    this compensation as a slight skip or echo periodically.

    Ref.: http://echolink.org/Help/default.htm -> Configuration -> Setup

system info:
    Fedore Core4
    Qtel:       qtel-0.9.0-2fc4.i386.rpm
    libasync:   libasync-0.12.1-1fc4.i386.rpm
    echolib:    echolib-0.10.2-1fc4.i386.rpm
    sound card: Multimedia audio controller: Cirrus Logic CS 4614/22/24
               [CrystalClear SoundFusion Audio Accelerator] (rev 01)

    strartup command: ASYNC_AUDIO_NOTRIGGER=1 /usr/bin/qtel


Pierre Thibaudeau

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