[jitsi-dev] Documentation for Voice Call


#1

Most of the support questions regarding voice calls are about sound
quality, absence of sound, and encryption. I focused on writing these
first (and will fill in the simple steps for making a call at a later date).

https://jitsi.org/Documentation/VoiceCall

Please review the accuracy of my description of end-to-end encryption
(particularly the section labeled "Limits of end-to-end encryption"),
since I only have a cursory understanding of the concepts.

In the Troubleshooting section I could use some help with the
recommended bandwidth and interpreting the call info statistics (see the
"Poor Internet connection" bullet). Would this section also benefit from
recommended codecs for particular uses, or will that just confuse the
situation?

Could processing power of the computer or device be a factor in audio
quality, if a CPU intensive codec is used?

I wrote, "Windows Audio Session API (WASAPI)" is recommended for Windows
Vista or later. "Port Audio" is recommended for Linux. What is
recommended for Mac OS?

David


#2

Most of the support questions regarding voice calls are about
sound quality, absence of sound, and encryption. I focused on
writing these first (and will fill in the simple steps for making a
call at a later date).

https://jitsi.org/Documentation/VoiceCall

Please review the accuracy of my description of end-to-end
encryption (particularly the section labeled "Limits of end-to-end
encryption"), since I only have a cursory understanding of the
concepts.

Metadata is a bit inaccurate in my opinion: I think there is a higher
probability of your ISP recording the metadata. (Most XMPP providers
will just delete every message after it has been delivered and Voice
and Video is not always routed over the provider)

Could processing power of the computer or device be a factor in
audio quality, if a CPU intensive codec is used?

I do not think that this is a problem for audio but I have seen cases
where encoding and encrypting the video overloaded a PC.

I wrote, "Windows Audio Session API (WASAPI)" is recommended for
Windows Vista or later. "Port Audio" is recommended for Linux. What
is recommended for Mac OS?

Port Audio is not recommended for Linux, it crashes jitsi when you
switch ttys, Pulseaudio is.

- --
Yannik V�lker

···

Am 16.09.2013 07:43, schrieb David Bolton:


#3

Hello, David

Most of the support questions regarding voice calls are about sound
quality, absence of sound, and encryption. I focused on writing these
first (and will fill in the simple steps for making a call at a later date).

https://jitsi.org/Documentation/VoiceCall

Great article!

Please review the accuracy of my description of end-to-end encryption
(particularly the section labeled "Limits of end-to-end encryption"),
since I only have a cursory understanding of the concepts.

From the article:

"Metadata The content of the conversation is private, but information
about the call (such as the accounts and IP addresses involved, and the
length and time of the call) are still visible to any intercepting
party, and often stored by your voice calling service."

I don't think this is quite accurate. If your connection to your
provider is secure (which it usually is), then the "accounts" are not
accessible by any intercepting party. For example, someone listening on
the wire (e.g. your ISP) could see that you connected to
xmpp.example.com, and that you had a media session with a certain IP
address, but they don't know which is your account on xmpp.example.com
or the XMPP address that you called.

In the Troubleshooting section I could use some help with the
recommended bandwidth and interpreting the call info statistics (see the
"Poor Internet connection" bullet). Would this section also benefit from
recommended codecs for particular uses, or will that just confuse the
situation?

Could processing power of the computer or device be a factor in audio
quality, if a CPU intensive codec is used?

I don't think so, at least not on any modern hardware.

I wrote, "Windows Audio Session API (WASAPI)" is recommended for Windows
Vista or later. "Port Audio" is recommended for Linux. What is
recommended for Mac OS?

As far as I know, at the moment PortAudio is the only option for Mac OS
X (although a CoreAudio implementation is in the works)

Regards,
Boris

···

On 9/16/13 7:43 AM, David Bolton wrote:


#4

That sounds weird. It doesn't crash jitsi while there is no call going
on, will try during a call when I get the chance (jitsi snapshot from
yesterday).

Is this the only reason why PulseAudio is recommended over PortAudio?

Regards,
Philipp

···

On Mon, 16 Sep 2013 15:51:28 +0200 Yannik Völker <yannikv@yahoo.de> wrote:

> I wrote, "Windows Audio Session API (WASAPI)" is recommended for
> Windows Vista or later. "Port Audio" is recommended for Linux. What
> is recommended for Mac OS?
Port Audio is not recommended for Linux, it crashes jitsi when you
switch ttys, Pulseaudio is.