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<body class='hmmessage'><div dir='ltr'><font style="" color="#000000" face="Tahoma,sans-serif">You ask a lot of questions. I will try to answer a few.<br><br>On the audio files most all I have checked are 8khz 16 bit. Where are you finding 8 bit?<br id="FontBreak"></font><br><font style="" face="Tahoma,sans-serif"> soxi /var/lib/asterisk/sounds/node.gsm</font><font style="" face="Tahoma,sans-serif"><br></font><font style="" face="Tahoma,sans-serif"><br></font><font style="" face="Tahoma,sans-serif">Input File : '/var/lib/asterisk/sounds/node.gsm'</font><font style="" face="Tahoma,sans-serif"><br></font><font style="" face="Tahoma,sans-serif">Channels : 1</font><font style="" face="Tahoma,sans-serif"><br></font><font style="" face="Tahoma,sans-serif">Sample Rate : 8000</font><font style="" face="Tahoma,sans-serif"><br></font><font style="" face="Tahoma,sans-serif">Precision : 16-bit</font><font style="" face="Tahoma,sans-serif"><br></font><font style="" face="Tahoma,sans-serif">Sample Encoding: GSM<br><br>While I am not aware that Asterisk can handle higher than 8khz files it may be that you can push it a little. I see no reason to do so though. Most of the voice is quite good. Certainly far better than the amateur RF digital crap that some hams seem to be admiring! Here is a good article and a link to a Digium converter you might find useful -<br><br> <a href="http://blogs.digium.com/2011/04/19/asterisk-sound-files-101/" target="_blank">http://blogs.digium.com/2011/04/19/asterisk-sound-files-101/</a><br> <br>As for levels. In the past, meaning the current code for the BBB and RPi2</font><font style="" face="Tahoma,sans-serif"> and Acid there has been no way to adjust the level of the telemetry so users often alter the levels of the individual sound files. The saytime script has the level capability built-in and there is a script called change_vol.sh to change the volume of a file. Some have wholesale changed the level of all sound files with a script. This is a crude way to do it but it works.<br><br>The update will have two new commands to change telemetry level without modifying any files. The commands are:<br><br>telemnomdb <value> and telemduckdb <value><br><br>telemnondb will change the level of the telemetry in dB. Typically you might want the telemetry to be lower by say 6 dB so the command would be telemnomdb -6<br><br>telemduckdb changes the level when a signal is present. Think of it as idtalkover for voice. The default value is -9 dB<br><br>These commands will go in the node section of rpt.conf and can be defined on a per node basis.<br><br>So with the 1.3 update for the BBB and RPi2 you will not have to fiddle with sound file volumes anymore.<br><br></font><b><font style="font-size:16pt;" face="Tahoma,sans-serif" size="4">73 Doug</font><font style="font-size:16pt;" size="4"><br></font><font style="font-size:16pt;" size="4">WA3DSP</font><font style="font-size:16pt;" size="4"><br></font><font style="font-size:16pt;" size="4">http://www.crompton.com/hamradio</font></b><font style="font-size:16pt;" size="4"><br></font><br><br><div><hr id="stopSpelling">From: wb9rsq@gmail.com<br>To: arm-allstar@hamvoip.org<br>Date: Thu, 11 Feb 2016 10:54:19 -0600<br>Subject: [arm-allstar] File extensions and audio format<br><br>
<title>File extensions and audio format</title>
<p dir="LTR"><span lang="en-us"><font face="Calibri">I know there have been threads on both of these topics but I’m not sure I understand the final advice or the driving policy</font></span><span lang="en-us"><font face="Calibri"> behind current practice.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">First the 1.2.1 image has lots of different script files.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Some are .pl</font></span><span lang="en-us"><font face="Calibri"> and others are .sh.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">There are even a few .py.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">I know what they are but there are also lots of files that are BASH scripts but don’t have a .sh extension.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Why in some cases do they have</font></span><span lang="en-us"><font face="Calibri"> extensions and in others they don’t?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Should they all have extensions?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Next the old audio thing again.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">The</font></span><span lang="en-us"><font face="Calibri"> asterisk sounds folder seems to have .gsm at 8khz 8 bit sampling.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Comments in several .sh files indicate that in order to use CAT you need to have all f</font></span><span lang="en-us"><font face="Calibri">iles formatted the same.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">That is obvious but no harm in pointing it out.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">However the files for the shutdown and reboot scripts are 8kh</font></span><span lang="en-us"><font face="Calibri">z 16 bit wave files.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">They play just fine through the radio nodes.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">In fact I’ve heard 11</font></span><span lang="en-us"><font face="Calibri">025 16 bit audio play fine as well.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Yes I can hear the difference in audio quality even over the radio between 8 and 16 bit.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">More so with higher sampling rates.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">So for some questions.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Where is the 8khz 8 bit limit coming from?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Is it really a limit or just best practice?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Forgetting the space issue is there any reason not to use a 16 bit 8khz or even slightly higher format?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Would ulaw or even wav be a better option for audio under local control?</font></span></p>
<p dir="LTR"><span lang="en-us"></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">The saytime script has a line to adjust the volume of the final audio output.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">The comment basically reads that negative numbers are lower and to see the sox man page for details.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">The script had 1.35 as the value.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Changing it to -1.35 resulted in</font></span><span lang="en-us"> <font face="Calibri">audio distorted and to loud to be useful at all.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Going above 2.0</font></span><span lang="en-us"> <font face="Calibri">seemed to be an upper limit</font></span><span lang="en-us"><font face="Calibri">.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Finally 0.0 resulted in silence.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">So I came to the conclusion that 0.0 to 2.0 was the effective working range of options.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Is this some kind of multiplying factor based on original audio level?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">I typically normalize audio to peak -1.5DB.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">I do that before placing audio in the sound libraries.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Would it be better to just normalize to something lower</font></span><span lang="en-us"><font face="Calibri"> to keep audio in line with other sources of TX audio?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">For audio outside my control would it be better to use a</font></span><span lang="en-us"> <font face="Calibri">sox process to normalize to the rest of my library?</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">What about just using sox to always normalize anything going out</font></span><span lang="en-us"><font face="Calibri"> or is the volume change method in the script the best approach?</font></span></p>
<p dir="LTR"><span lang="en-us"></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">Any thoughts</font></span><span lang="en-us"> <font face="Calibri">on these issues would be appreciated.</font></span></p>
<p dir="LTR"><span lang="en-us"><font face="Calibri">73</font></span></p>
<p dir="LTR"><span lang="en-us"></span></p>
<p dir="LTR"><span lang="en-us"></span></p>
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