<div dir="ltr">See if this helps -<br><a href="http://www.voip-info.org/wiki/view/Call+Quality+Metrics">http://www.voip-info.org/wiki/view/Call+Quality+Metrics</a><br><a href="http://www.tamos.com/htmlhelp/voip-analysis/mosandr_factor.htm">http://www.tamos.com/htmlhelp/voip-analysis/mosandr_factor.htm</a><br><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Apr 9, 2015 at 3:18 PM, Stanislav Sinyagin <span dir="ltr"><<a href="mailto:ssinyagin@gmail.com" target="_blank">ssinyagin@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I made additional tests, and... I'm not sure any more. So, I removed<br>
the statement about bad precision. This needs a lab environment with<br>
predictable network and known CPU load on the host machine.<br>
<br>
Does anyone know any tools that would automatically detect sound<br>
distortions in WAV files and also find the shifts because of slipping<br>
clock or lost frames? Up to now, the only tool I could find is<br>
visually comparing the waves in Audacity.<br>
<span class="im HOEnZb"><br>
<br>
<br>
On Sun, Apr 5, 2015 at 2:37 AM, Stanislav Sinyagin <<a href="mailto:ssinyagin@gmail.com">ssinyagin@gmail.com</a>> wrote:<br>
</span><div class="HOEnZb"><div class="h5">> here we go:<br>
> <a href="https://txlab.wordpress.com/2015/04/05/testing-rtp-clock-precision-on-a-virtual-machine/" target="_blank">https://txlab.wordpress.com/2015/04/05/testing-rtp-clock-precision-on-a-virtual-machine/</a><br>
><br>
><br>
><br>
> On Sat, Apr 4, 2015 at 4:26 PM, Stanislav Sinyagin <<a href="mailto:ssinyagin@gmail.com">ssinyagin@gmail.com</a>> wrote:<br>
>> On Sat, Apr 4, 2015 at 1:03 PM, Regis M <<a href="mailto:regis.freeswitch.org@tornad.net">regis.freeswitch.org@tornad.net</a>> wrote:<br>
>>> How do you check wavs together in audacity ?<br>
>><br>
>> you just open two WAV files, align their starting position, and<br>
>> visually check the waves. If there's a problem, you would see that<br>
>> after few seconds, the waves are not aligned any more.<br>
>><br>
>>> Can you send me 2 samples wav (send... and recorded) so I could see the 20ms<br>
>>> diff that you exposed...<br>
>>><br>
>>> Is there a way to automate the result checking, so it could help to monitor<br>
>>> itsp quality<br>
>><br>
>> Here<br>
>> <a href="https://github.com/openpreserve/scape-xcorrsound/issues/17" target="_blank">https://github.com/openpreserve/scape-xcorrsound/issues/17</a><br>
>> this is a link to a tool which compares two sound files at the wave<br>
>> level. You can also see the sound samples in the ticket.<br>
>> The problem is, that currently this tool does not detect such slipping frames.<br>
>><br>
>> I will also write a detailed article with examples, during the weekend.<br>
>><br>
>><br>
>><br>
>><br>
>><br>
>>><br>
>>><br>
>>> 2015-04-04 12:53 GMT+02:00 Stanislav Sinyagin <<a href="mailto:ssinyagin@gmail.com">ssinyagin@gmail.com</a>>:<br>
>>>><br>
>>>> Important is to send the media through two independent carriers - then you<br>
>>>> can be sure that your clock is compared against a high quality one.<br>
>>>><br>
>>>> On Apr 4, 2015 12:46 PM, "Regis M" <<a href="mailto:regis.freeswitch.org@tornad.net">regis.freeswitch.org@tornad.net</a>><br>
>>>> wrote:<br>
>>>>><br>
>>>>> Hi,<br>
>>>>><br>
>>>>> It's a very interresting test and conclusion.<br>
>>>>><br>
>>>>> I will try to build a similar environnement on my freeswitch to check<br>
>>>>> some system :)<br>
>>>>><br>
>>>>> thanks<br>
>>>>><br>
>>>>><br>
>>>>><br>
>>>>> 2015-04-04 2:16 GMT+02:00 Stanislav Sinyagin <<a href="mailto:ssinyagin@gmail.com">ssinyagin@gmail.com</a>>:<br>
>>>>>><br>
>>>>>> hi,<br>
>>>>>><br>
>>>>>> Here are some test results which might be interesting:<br>
>>>>>><br>
>>>>>> I've set up a test FreeSWITCH server at digitalocean (they use KVM),<br>
>>>>>> and originated test calls to some ITSP accounts. Each call played a<br>
>>>>>> test sound file (voice samples from ITU:<br>
>>>>>> <a href="http://www.itu.int/net/itu-t/sigdb/genaudio/AudioForm-g.aspx?val=1000050" target="_blank">http://www.itu.int/net/itu-t/sigdb/genaudio/AudioForm-g.aspx?val=1000050</a><br>
>>>>>> ), and on the receiving end another FreeSWITCH server was recording<br>
>>>>>> the received session. The receiving server was on a XEN VM. Both<br>
>>>>>> servers talked G711 to their corresponding ITSP accounts.<br>
>>>>>><br>
>>>>>> Then I compared the source audio and received audio in Audacity editor.<br>
>>>>>><br>
>>>>>> The tests showed that the received voice wave shifts 20ms from the<br>
>>>>>> original sound every few seconds, randomly back and forward. This<br>
>>>>>> skewing was always present, regardless of ITSP and time of day.<br>
>>>>>><br>
>>>>>> Then I moved the sending server to a XEN VM, and the waves appeared<br>
>>>>>> almost perfectly synchronized (there was a 5ms skew in one test, and I<br>
>>>>>> guess it's related to transcoding buffer, as the sound was obviously<br>
>>>>>> transcoded).<br>
>>>>>><br>
>>>>>> The effect was always visible with a 30-second sample, and I also made<br>
>>>>>> additional tests with 2-minute samples.<br>
>>>>>><br>
>>>>>> It would also be interesting to test this from a VmWare VM. If someone<br>
>>>>>> wants to run such a test, feel free to contact me directly.<br>
>>>>>><br>
>>>>>><br>
>>>>>> cheers,<br>
>>>>>> stan<br>
>>>>>><br>
>>>>>><br>
>>>>>> _________________________________________________________________________<br>
>>>>>> Professional FreeSWITCH Consulting Services:<br>
>>>>>> <a href="mailto:consulting@freeswitch.org">consulting@freeswitch.org</a><br>
>>>>>> <a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
>>>>>><br>
>>>>>> Official FreeSWITCH Sites<br>
>>>>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>>>>> <a href="http://confluence.freeswitch.org" target="_blank">http://confluence.freeswitch.org</a><br>
>>>>>> <a href="http://www.cluecon.com" target="_blank">http://www.cluecon.com</a><br>
>>>>>><br>
>>>>>> FreeSWITCH-users mailing list<br>
>>>>>> <a href="mailto:FreeSWITCH-users@lists.freeswitch.org">FreeSWITCH-users@lists.freeswitch.org</a><br>
>>>>>> <a href="http://lists.freeswitch.org/mailman/listinfo/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/listinfo/freeswitch-users</a><br>
>>>>>> UNSUBSCRIBE:<a href="http://lists.freeswitch.org/mailman/options/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/options/freeswitch-users</a><br>
>>>>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>>>><br>
>>>>><br>
>>>>><br>
>>>>> _________________________________________________________________________<br>
>>>>> Professional FreeSWITCH Consulting Services:<br>
>>>>> <a href="mailto:consulting@freeswitch.org">consulting@freeswitch.org</a><br>
>>>>> <a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
>>>>><br>
>>>>> Official FreeSWITCH Sites<br>
>>>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>>>> <a href="http://confluence.freeswitch.org" target="_blank">http://confluence.freeswitch.org</a><br>
>>>>> <a href="http://www.cluecon.com" target="_blank">http://www.cluecon.com</a><br>
>>>>><br>
>>>>> FreeSWITCH-users mailing list<br>
>>>>> <a href="mailto:FreeSWITCH-users@lists.freeswitch.org">FreeSWITCH-users@lists.freeswitch.org</a><br>
>>>>> <a href="http://lists.freeswitch.org/mailman/listinfo/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/listinfo/freeswitch-users</a><br>
>>>>> UNSUBSCRIBE:<a href="http://lists.freeswitch.org/mailman/options/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/options/freeswitch-users</a><br>
>>>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>>><br>
>>>><br>
>>>> _________________________________________________________________________<br>
>>>> Professional FreeSWITCH Consulting Services:<br>
>>>> <a href="mailto:consulting@freeswitch.org">consulting@freeswitch.org</a><br>
>>>> <a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
>>>><br>
>>>> Official FreeSWITCH Sites<br>
>>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>>> <a href="http://confluence.freeswitch.org" target="_blank">http://confluence.freeswitch.org</a><br>
>>>> <a href="http://www.cluecon.com" target="_blank">http://www.cluecon.com</a><br>
>>>><br>
>>>> FreeSWITCH-users mailing list<br>
>>>> <a href="mailto:FreeSWITCH-users@lists.freeswitch.org">FreeSWITCH-users@lists.freeswitch.org</a><br>
>>>> <a href="http://lists.freeswitch.org/mailman/listinfo/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/listinfo/freeswitch-users</a><br>
>>>> UNSUBSCRIBE:<a href="http://lists.freeswitch.org/mailman/options/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/options/freeswitch-users</a><br>
>>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>><br>
>>><br>
>>><br>
>>> _________________________________________________________________________<br>
>>> Professional FreeSWITCH Consulting Services:<br>
>>> <a href="mailto:consulting@freeswitch.org">consulting@freeswitch.org</a><br>
>>> <a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
>>><br>
>>> Official FreeSWITCH Sites<br>
>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
>>> <a href="http://confluence.freeswitch.org" target="_blank">http://confluence.freeswitch.org</a><br>
>>> <a href="http://www.cluecon.com" target="_blank">http://www.cluecon.com</a><br>
>>><br>
>>> FreeSWITCH-users mailing list<br>
>>> <a href="mailto:FreeSWITCH-users@lists.freeswitch.org">FreeSWITCH-users@lists.freeswitch.org</a><br>
>>> <a href="http://lists.freeswitch.org/mailman/listinfo/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/listinfo/freeswitch-users</a><br>
>>> UNSUBSCRIBE:<a href="http://lists.freeswitch.org/mailman/options/freeswitch-users" target="_blank">http://lists.freeswitch.org/mailman/options/freeswitch-users</a><br>
>>> <a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
<br>
_________________________________________________________________________<br>
Professional FreeSWITCH Consulting Services:<br>
<a href="mailto:consulting@freeswitch.org">consulting@freeswitch.org</a><br>
<a href="http://www.freeswitchsolutions.com" target="_blank">http://www.freeswitchsolutions.com</a><br>
<br>
Official FreeSWITCH Sites<br>
<a href="http://www.freeswitch.org" target="_blank">http://www.freeswitch.org</a><br>
<a href="http://confluence.freeswitch.org" target="_blank">http://confluence.freeswitch.org</a><br>
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<br>
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</div></div></blockquote></div><br></div>