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I use SPDIF passthrough on my main HTPC and pump the digital stream
directly to my Harmon Kardon 5.1 receiver. No horrible screetches or
pops, just drop-outs when the signal drops out. On my remote frontend,
however, I'm just using the default /dev/dsp which does the horrible
popping/screetching sounds. VERY annoying and I, too, fear damage to
the audio system. Apparently the receiver is smart enough to ignore
digital drop-outs. Or is it the ALSA:spdif driver that just sends
zeros (quiet) during those drop-outs (or more accurately, at the
transitions). Is it corrupts data bits? Maybe the receiver ignores
anything non-sinusoidal. Seems like one could implement such a filter
in one's sound driver. I'd LOVE to find a solution.<br>
<br>
DaveD<br>
<br>
JJ wrote:
<blockquote cite="mid:476D10EA.7010102@eastlink.ca" type="cite">
<pre wrap="">Cal wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Bryan Murphy wrote:
</pre>
<blockquote type="cite">
<pre wrap="">On Dec 21, 2007 2:09 AM, Cal <a class="moz-txt-link-rfc2396E" href="mailto:cal@graggrag.com"><cal@graggrag.com></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">[ ... ] the bottom line is - _only_ mythtv screeches!
</pre>
</blockquote>
<pre wrap="">Yeah, being able to describe the problem (and point the way to
possible solutions) is also helpful. Somebody else in this thread
mentioned the term "compander" which I had not heard before, so I've
been doing a little more research. Who knows what doors that might
open up. Anyway, I've done a bit of audio processing myself in the
past for my employer, so maybe when I have some more time after the
holiday, if I can't solve the problem myself, I might at least be able
to point the appropriate people in the right direction.
</pre>
</blockquote>
<pre wrap="">As I understand it, a compander involves dynamic compression _and_ expansion
of the dynamic range, so I'm not sure a "compander" fits the problem. It's
perhaps in the right ballpark for a bandaid fix though. For the screeches,
I think just peak limiting might be more appropriate. It's been a while since
I followed the linux-audio-users mailing list, but it might be worth exploring
their archives and floating a query there
<a class="moz-txt-link-rfc2396E" href="http://music.columbia.edu/mailman/listinfo/linux-audio-user/"><http://music.columbia.edu/mailman/listinfo/linux-audio-user/></a>.
It's been a while since I used it, and it's relevance to our myth issue is low,
but Jamin
<a class="moz-txt-link-rfc2396E" href="http://jamin.sourceforge.net/en/about.html"><http://jamin.sourceforge.net/en/about.html></a>
is the only example of audio compression & limiting I'm aware of. An outstanding
application though.
Health & time permitting, I'd like to take a look at the waveform of the
screeches. That might give a clue as to whether peak limiting might ease the
impact. I suspect not though, the deeper problem is the one that counts.
Cheers.
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</pre>
</blockquote>
<pre wrap=""><!---->Yes, I'd agree that peaklimiting would be a band-aid solution....oh, and
the reason I'd mentioned a "compander"
is that it'd be really really neat to be able to restore the dynamic
range that a lot of media has, some is compressed, some
is too dynamic, lol!
Happy ho-ho everyone..
JJ
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</pre>
</blockquote>
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