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Hello Albert,<br>
<br>
Thanks for your clear explanation and the nice recall of our funny
early-life! I still have my 33 LP & 45 rpm discs collection but
I have lost my player. ;-)<br>
<br>
Well, so I was too demanding regarding the capabilities of such
Audio objects.<br>
I was wrongly expecting more or less the same good behavior
out-of-the-box than e.g. VLC which is capable to read an Audio file
recorded at 44.1 KHz and to play it back automatically at the right
speed/tone using the "vlc-plugin-jack" (without any particular
setting) when its Audio output is using the JACK server set up at 48
KHz.<br>
<br>
So, I do need to spend some time to find out how I can easily
implement such mechanism within my Purr Data projects by e.g.
reading the relevant part of the Audio file header and then decide
what to do either with/around the given Audio player object and/or
Purr Data settings. I'm continuing to learn each day.<br>
<br>
What a wonderful community!<br>
<br>
Best, Joseph<br>
<div class="moz-signature">- - - - - - - - - -<br>
</div>
<div class="moz-cite-prefix"><br>
Le 15/10/2020 à 01:14, Albert Graef a écrit :<br>
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<blockquote type="cite"
cite="mid:CA+rUic16nRWKX0=yB=DLKteMAX6t5C3EF7RD+7yrCPBE=GZoAQ@mail.gmail.com">
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<div>Hi Joseph,</div>
<div><br>
</div>
<div>Well, if you read something into a Pd array at sample rate
SR1, and then play that sample data back later (through Jack
or otherwise) at sample rate SR2, then it will play back with
a speedup/slowdown factor of SR2/SR1, and pitch will shift by
the same factor. The audio interface doesn't care where those
numbers come from. It will happily play 48000 samples of your
44.1kHz-sampled data in 1 sec, which will speed it up by a
factor of 48000/44100 = 108.8% and make it sound about 1.5
semitones higher.</div>
<div><br>
</div>
<div>At least that's what happens if the object decoding the ogg
file doesn't convert to the target sample rate on the fly. I'm
not sure whether oggread~ does this.<br>
</div>
<div><br>
</div>
<div>Joseph, I'm sure you also still remember those glorious
days when we enjoyed playing back those black "LP" discs at 45
rpm. It's the same effect, only in digital. ;-)</div>
<div><br>
</div>
<div>HTH,</div>
<div>Albert</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Oct 14, 2020 at 10:48
PM Linux ROUEN Normandie <<a
href="mailto:linux.rouen@free.fr" moz-do-not-send="true">linux.rouen@free.fr</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello
to the Audio specialists,<br>
<br>
I'm struggling since a while with an annoying Audio issue
under Purr <br>
Data using e.g. [oggwrite~] / [oggread~] with their default
settings.<br>
<br>
Under GNU/Linux for Audio I'm using JACK2 with QJackCtl or
Ubuntu Studio <br>
Control and JACK back-end = ALSA.<br>
I record from an Audio source (synth, micro, line) with
[oggwrite~] and <br>
then play it back with [oggread~].<br>
<br>
As long as I'm using everywhere (Pd, Jack) the same Sample
Rate, either <br>
44100 or 48000, it's all fine - no issue at all.<br>
But if the Play SR changes (voluntary or not in Pd & Jack)
vs the Record <br>
SR, then when playing my Audio song back is running either
faster or slower!<br>
<br>
I thought that the Audio SR had nothing to do with the
playback speed <br>
but only, among other things, with the sound quality.<br>
<br>
What is wrong in my thinking? Any ideas?<br>
<br>
Thank you. Best,<br>
Joseph Gastelais<br>
<br>
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<br clear="all">
<br>
-- <br>
<div dir="ltr" class="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">Dr. Albert Gr"af<br>
Computer Music Research Group, JGU Mainz, Germany<br>
Email: <a href="mailto:aggraef@gmail.com"
target="_blank" moz-do-not-send="true">aggraef@gmail.com</a>,
web: <a href="https://agraef.github.io/"
target="_blank" moz-do-not-send="true">https://agraef.github.io/</a></div>
</div>
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