Re: [Linphone-users] - Linphone for music lessons

[mailing list]

Good evening and thank you very much to all for the answers!

Now I start to understand better, I didn’t know that the SIP server also 
affected the audio CODECS possibilities. I don't know if Linphone SIP 
free account supports Opus Wide, I hope yes.


I have initially thought to Linphone or Jami, the possibility to choose 
the bandwidth of Linphone is very nice, but now it seems me from your 
answers that a WebRCT based situation such as Jitsi could perhaps be the 
best for music, I also saw that there is a service, currently in beta, 
based on Jitsi and optimized for music: https://sirius.video/ I'm 
curious to try it out.


Searching on the web I also read about a use of Jamulus, which however 
requires the server Jack, for the audio together with a software like 
Jitsi or similar for the video.


I have to do some tests, at this point I should perhaps start from Jitsi 
or maybe from Sirius, which is already optimized for music, before 
thinking about software on SIP protocol.


Thank you again and best regards,

Stephanie

Il 17/12/20 03:13, Stuart Elvish - STU Telecom Inc ha scritto:

Good afternoon Maciej and Ms. Cortelli,

I can only provide very basic additional comments but this post caught 
my attention.


I use Zoom several times a week to attend religious meetings (which 
includes pre-recorded video and music as well as live speech) and 
noticed that Zoom typically offers a decent but not outstanding audio 
codec (I remember the number 24 but can't remember if that was KHz or 
Kbps). The information is available in the statistics panel during a 
screen share. If the audio is live then the clarity is scaled up/down 
and you can run into some very serious issues which would result in a 
sound that is not at all acceptable for music. The scaling is dynamic; 
it is based on the person's internet connection, what equipment they 
have etc, etc (and which way the wind is blowing). Other factors such 
as the load on Zoom's servers (which has nothing to do with you or 
your student) seem to also affect the quality but that is an anecdotal 
observation. To summarise; Zoom is not reliable enough in my opinion. 
During a meeting use the statistics information to see what quality 
the audio is being transmitted at.


Also, Zoom uses noise gates (minimum thresholds for opening the audio 
channel), background noise suppression algorithms and a few other 
fancy tricks which are great for selective switching of videos and 
preventing audio feedback but not so good for music.


Linphone has the advantage that it can use high bandwidth/high quality 
codecs (forced codecs, you can control it to a certain extent) as well 
as do the other things Zoom is capable of (primarily being able to 
push video along with the audio). You can connect microphones to the 
tablet/laptop/phone and achieve a nice audio feed through Linphone. 
But, however hard you try, I am not sure you will achieve a result as 
good as recording the audio with software local to the student. All 
codecs have frequency limitations (equivalent of high and low pass 
filters) and whilst this is not a problem for voice, it may be an 
issue for musical instruments especially those producing higher 
pitched notes. And some codecs look like they're wide band but it can 
depend on the configuration/setup of the system and endpoints as to 
whether or not you can use the full wideband capability. The easiest 
way I found to show it is 
https://developer.mozilla.org/en-US/docs/Web/Media/Formats/Audio_codecs#Opus 



Another suggestion I would make is to look at WebRTC. This requires 
more infrastructure but if lockdown doesn't end any time soon it might 
be a good way of achieving a better result. I am not sure if you are 
teaching as part of a school, as part of a group etc but there may be 
someone who can give you better advice on WebRTC and if it will work 
well with your situation. WebRTC also allows someone to connect to the 
meeting via a web browser and that likely makes picking up the 
microphone feed much easier.


Kind regards
Stuart

On Thu, 17 Dec 2020 at 11:29, Maciej Morycinski > wrote:


Dear Ms. Cortelli,

Your idea is wonderful, and maybe some company already created a
product that would suit your needs exactly. It would certainly
make sense to research that in professional music circles.

However, when it comes to using a SIP phone such as Linphone, it
is probably the wrong tool for this particular job.

Issue #1 is with the codec. Despite your impression re Zoom, it is
not possible at all to transfer sound across the Internet without
using _some_ codec. Zoom certainly uses a default one.
If it is possible to select Opus Wide using Zoom, that might work
for you. There are various codecs appropriate for different tasks,
but most of them are unsuitable for music, as many are specifically

Re: [Linphone-users] H265 vs H264 not optimizing bandwidth + other feedback

[ael via Linphone-users]

On Thu, Dec 17, 2020 at 07:47:30AM +, Alan Azar wrote:
> 
> USER FORUM
> I really wish you would move away from a mailing list to a forum. It will 
> make it easier to manage feedback + retain knowledge for users searching for 
> topics that may have already been covered.

That is a bit controversial. Forums (fora?) are a pain. You have to
remember to visit them and they are not easy to search with standard
tools like grep. I am not sure if this mailing list is archived, but
if so, even a newcomer can find past topics easily. A forum is
also expensive in resources and forces one to use a browser or
wahtever. Use simple tried and tested tools when they are more than
adequate.

ael


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[Linphone-users] H265 vs H264 not optimizing bandwidth + other feedback

[Alan Azar]

Hello,

First-time poster - thank you for all your hard work. I have a few questions \ 
feedback I'd like to give.

H265 vs H264
I have noticed testing between 2 devices on an internal home network that H265 
provides better 720p quality as expected, however the bandwidth is the same as 
720p on H264.
I remember about a year ago while testing this, I used to get better 720p at 
about a quarter of H264 that's not happening anymore. Can anyone validate 
this?
FPS is stable at ~25fps in both cases


OPTION TO CHANGE QUALITY\FPS IN A CALL
As the title says


ORDER OF CODECS
Can we have an option to re-order the codecs to use.
I have 2 devices that can do H265+H264 and another that only does H264.
I have to manually unselect the H264 to make a high quality call, but then turn 
it back when i call the device that only supports H264.
Is there a way to re-order the codecs so it tries the H265 first and then H264 
if H265 undetected?


AV1 CODEC
After reading an article by Gary Sims (Aug 2 2020), I believe the limitation 
here is the time to encode \ decode may not be feasible for this application & 
current devices.
However, is there any news on a high quality royalty free codec that may be 
available for Linphone?


LOAD CONFIG FILE
Option to save and load a config file with all settings


USER FORUM
I really wish you would move away from a mailing list to a forum. It will make 
it easier to manage feedback + retain knowledge for users searching for topics 
that may have already been covered.


Other than that, I wish you all a Merry Christmas \ Happy Holidays and a 
wonderful New Year!
Thank you for everything!
Alan
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