implementing stereo (e.g. portaudio to test it easily)
hello FreeSWITCH community, actually it is my first time to use lists like this. I hope I do everything fine. For my project I try to get stereo (and some special features later) integrated in freeSWITCH, especially SIP. TO start with this idea I need to know where I have to activate or implement stereo. In the second I try to play a bit with the portaudio module as I do not have to focus on SDP problems transporting SIP and the need of a SIP client which is able to receive stereo. So I set up some custom moh local media stuff which works finde - using mono. Changing the channels to 2 makes the console telling me that the sound file will be mixed to mono and the sound is quite strange. I would be happy about getting some useful information which modules or configs are the important ones for my idea. Unfurtun ately I have only found some recording stuff about stereo which is not what I want to do. Thank you very much. MatzeMuc86
Sorry, FreeSWITCH is not set up to do stereo... perhaps one day, but it isn't something that is high on the priority list. -MC On Thu, Feb 24, 2011 at 9:22 AM, MatzeMuc86 <matzemuc86@gmail.com> wrote:
hello FreeSWITCH community,
actually it is my first time to use lists like this. I hope I do everything fine. For my project I try to get stereo (and some special features later) integrated in freeSWITCH, especially SIP. TO start with this idea I need to know where I have to activate or implement stereo. In the second I try to play a bit with the portaudio module as I do not have to focus on SDP problems transporting SIP and the need of a SIP client which is able to receive stereo. So I set up some custom moh local media stuff which works finde - using mono. Changing the channels to 2 makes the console telling me that the sound file will be mixed to mono and the sound is quite strange. I would be happy about getting some useful information which modules or configs are the important ones for my idea. Unfurtun ately I have only found some recording stuff about stereo which is not what I want to do.
Thank you very much. MatzeMuc86
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Are you sure? I had a diskussion at the IRC dev channel and Grmt told me it should be possible. It is quite important for me and i do not ask somebody to implement this for me. Thanks MatzeMuc86 2011/2/24 Michael Collins <msc@freeswitch.org>
Sorry, FreeSWITCH is not set up to do stereo... perhaps one day, but it isn't something that is high on the priority list.
-MC
On Thu, Feb 24, 2011 at 9:22 AM, MatzeMuc86 <matzemuc86@gmail.com> wrote:
hello FreeSWITCH community,
actually it is my first time to use lists like this. I hope I do everything fine. For my project I try to get stereo (and some special features later) integrated in freeSWITCH, especially SIP. TO start with this idea I need to know where I have to activate or implement stereo. In the second I try to play a bit with the portaudio module as I do not have to focus on SDP problems transporting SIP and the need of a SIP client which is able to receive stereo. So I set up some custom moh local media stuff which works finde - using mono. Changing the channels to 2 makes the console telling me that the sound file will be mixed to mono and the sound is quite strange. I would be happy about getting some useful information which modules or configs are the important ones for my idea. Unfurtun ately I have only found some recording stuff about stereo which is not what I want to do.
Thank you very much. MatzeMuc86
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If I remember well I think you mentioned that anthm said that it was possible. I just gave you a quick intro into FS. Did you buy the book? And read it? Did you spend at least a week playing with FS? Did you spend at least that amount of time with your development environment? Did you debug the scenario I presented to you and inspect the source code? If you did, you should be able to make a rough order of magnitude estimation of the effort needed to make this scenario do stereo. And additionally, you would know if your skills and tenacity match the task you have set out for yourself. Given your background and the amount of time you have, I think you should be able to do your project. I would start by looking at the code right there were it tells you that it converts to mono. And again, given my level of expertise in FS or coding or codecs or whatever, I cannot help you any further, but I hope to see you become a FS expert so that I can have a stereo conversation with you in a few months. From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of MatzeMuc86 Sent: Thursday, 24 February, 2011 21:49 To: FreeSWITCH Users Help Subject: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily) Are you sure? I had a diskussion at the IRC dev channel and Grmt told me it should be possible. It is quite important for me and i do not ask somebody to implement this for me. Thanks MatzeMuc86 2011/2/24 Michael Collins <msc@freeswitch.org> Sorry, FreeSWITCH is not set up to do stereo... perhaps one day, but it isn't something that is high on the priority list. -MC On Thu, Feb 24, 2011 at 9:22 AM, MatzeMuc86 <matzemuc86@gmail.com> wrote: hello FreeSWITCH community, actually it is my first time to use lists like this. I hope I do everything fine. For my project I try to get stereo (and some special features later) integrated in freeSWITCH, especially SIP. TO start with this idea I need to know where I have to activate or implement stereo. In the second I try to play a bit with the portaudio module as I do not have to focus on SDP problems transporting SIP and the need of a SIP client which is able to receive stereo. So I set up some custom moh local media stuff which works finde - using mono. Changing the channels to 2 makes the console telling me that the sound file will be mixed to mono and the sound is quite strange. I would be happy about getting some useful information which modules or configs are the important ones for my idea. Unfurtun ately I have only found some recording stuff about stereo which is not what I want to do. Thank you very much. MatzeMuc86 _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org
Hehe, In other words, you didn't tell him: Just flip this switch and you can have stereo. :) It's a lot of work but an expert could definitely do it. DISCLAIMER: I am not such an expert. :P -MC On Thu, Feb 24, 2011 at 3:47 PM, Grmt <garmt.noname@gmail.com> wrote:
If I remember well I think you mentioned that anthm said that it was possible.
I just gave you a quick intro into FS.
Did you buy the book? And read it?
Did you spend at least a week playing with FS?
Did you spend at least that amount of time with your development environment?
Did you debug the scenario I presented to you and inspect the source code?
If you did, you should be able to make a rough order of magnitude estimation of the effort needed to make this scenario do stereo. And additionally, you would know if your skills and tenacity match the task you have set out for yourself.
Given your background and the amount of time you have, I think you should be able to do your project.
I would start by looking at the code right there were it tells you that it converts to mono.
And again, given my level of expertise in FS or coding or codecs or whatever, I cannot help you any further, but I hope to see you become a FS expert so that I can have a stereo conversation with you in a few months…
*From:* freeswitch-users-bounces@lists.freeswitch.org [mailto: freeswitch-users-bounces@lists.freeswitch.org] *On Behalf Of *MatzeMuc86 *Sent:* Thursday, 24 February, 2011 21:49 *To:* FreeSWITCH Users Help *Subject:* Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily)
Are you sure? I had a diskussion at the IRC dev channel and Grmt told me it should be possible. It is quite important for me and i do not ask somebody to implement this for me.
Thanks MatzeMuc86
2011/2/24 Michael Collins <msc@freeswitch.org>
Sorry, FreeSWITCH is not set up to do stereo... perhaps one day, but it isn't something that is high on the priority list.
-MC
On Thu, Feb 24, 2011 at 9:22 AM, MatzeMuc86 <matzemuc86@gmail.com> wrote:
hello FreeSWITCH community,
actually it is my first time to use lists like this. I hope I do everything fine. For my project I try to get stereo (and some special features later) integrated in freeSWITCH, especially SIP. TO start with this idea I need to know where I have to activate or implement stereo. In the second I try to play a bit with the portaudio module as I do not have to focus on SDP problems transporting SIP and the need of a SIP client which is able to receive stereo. So I set up some custom moh local media stuff which works finde - using mono. Changing the channels to 2 makes the console telling me that the sound file will be mixed to mono and the sound is quite strange. I would be happy about getting some useful information which modules or configs are the important ones for my idea. Unfurtun ately I have only found some recording stuff about stereo which is not what I want to do.
Thank you very much. MatzeMuc86
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Hello, OK I'm sure that I am not such an expert. I have done some C, but it's in the past (which shouldn't be a big problem). C++ is a bigger problem but it seams to be C, not C++ (?). Of course I read the book, played with freeswitch and did some debugging (problems with debugging are written below). I created a stream local media extension to play a stereo 32 kHz wav file. So far it is down mixed to mono in the switch_core_file.c file. I could find an online documentation about this c file by doxygen: http://www.freeswitch.org/eg/dox/switch__core__file_8c.html I checked the code and found some positions where fh->channels have to be > 1. All in all I can try to get these functions ready for stereo, but I have the feeling that this is only one very small problem regarding to my whole idea. I think about debugging the whole "pa call 1987" progress but therefore I need to know where to put the first debug point => where does the program starts executing my custom extension? In addition: Is there some further documentation or is the doxygen, mostly the same as the pure C code, all I can get for code-documentations (e.g. what are all the variables, what are the ideas e.g.). Thanks a lot MatzeMuc86 Von: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] Im Auftrag von Michael Collins Gesendet: Freitag, 25. Februar 2011 04:20 An: FreeSWITCH Users Help Betreff: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily) Hehe, In other words, you didn't tell him: Just flip this switch and you can have stereo. :) It's a lot of work but an expert could definitely do it. DISCLAIMER: I am not such an expert. :P -MC On Thu, Feb 24, 2011 at 3:47 PM, Grmt <garmt.noname@gmail.com> wrote: If I remember well I think you mentioned that anthm said that it was possible. I just gave you a quick intro into FS. Did you buy the book? And read it? Did you spend at least a week playing with FS? Did you spend at least that amount of time with your development environment? Did you debug the scenario I presented to you and inspect the source code? If you did, you should be able to make a rough order of magnitude estimation of the effort needed to make this scenario do stereo. And additionally, you would know if your skills and tenacity match the task you have set out for yourself. Given your background and the amount of time you have, I think you should be able to do your project. I would start by looking at the code right there were it tells you that it converts to mono. And again, given my level of expertise in FS or coding or codecs or whatever, I cannot help you any further, but I hope to see you become a FS expert so that I can have a stereo conversation with you in a few months. From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of MatzeMuc86 Sent: Thursday, 24 February, 2011 21:49 To: FreeSWITCH Users Help Subject: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily) Are you sure? I had a diskussion at the IRC dev channel and Grmt told me it should be possible. It is quite important for me and i do not ask somebody to implement this for me. Thanks MatzeMuc86 2011/2/24 Michael Collins <msc@freeswitch.org> Sorry, FreeSWITCH is not set up to do stereo... perhaps one day, but it isn't something that is high on the priority list. -MC On Thu, Feb 24, 2011 at 9:22 AM, MatzeMuc86 <matzemuc86@gmail.com> wrote: hello FreeSWITCH community, actually it is my first time to use lists like this. I hope I do everything fine. For my project I try to get stereo (and some special features later) integrated in freeSWITCH, especially SIP. TO start with this idea I need to know where I have to activate or implement stereo. In the second I try to play a bit with the portaudio module as I do not have to focus on SDP problems transporting SIP and the need of a SIP client which is able to receive stereo. So I set up some custom moh local media stuff which works finde - using mono. Changing the channels to 2 makes the console telling me that the sound file will be mixed to mono and the sound is quite strange. I would be happy about getting some useful information which modules or configs are the important ones for my idea. Unfurtun ately I have only found some recording stuff about stereo which is not what I want to do. Thank you very much. MatzeMuc86 _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org
MatzeMuc86 wrote:
I checked the code and found some positions where fh->channels have to be
1. This also depends on when the flags is set to SWITCH_FILE_FLAG_READ, right?
BTW, I am just curious what kind of application will you be making that requires a stereo. Do you care to tell us? Perhaps, once the readers understand what your application is, there may be some interests. ----- FreeSWITCH hosted on a Seagate DockStar with OpenWRT. -- View this message in context: http://freeswitch-users.2379917.n2.nabble.com/implementing-stereo-e-g-portau... Sent from the freeswitch-users mailing list archive at Nabble.com.
SWITCH_FILE_FLAG_READ: I'm not sure what this does. It's somewhere else in the code. My idea: A conference room for regular sip clients but also special user clients which can receive stereo. Stereo is needed as those clients will get a special HRTF sound: different people are placed on different 3D positions in the room and you can hear them. This is NOT regular stereo sound but real 3D sound. Why is this better: Mixing all together to one mono channel, it is very difficult to distinguish between different people. Interesting links: http://en.wikipedia.org/wiki/Head-related_transfer_function and http://en.wikipedia.org/wiki/Cocktail_party_effect. There have been several tests (and there is literature as well) that proofs that it is much easier to follow conversations which use 3D sound like HRTF. And I want to do this not by some proprietary software like it is done by with Mumble by J. Feldmayer but with SIP to be able to connect also regular SIP clients (and regular phones or whatever I want). -----Ursprüngliche Nachricht----- Von: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] Im Auftrag von mazilo Gesendet: Freitag, 25. Februar 2011 15:13 An: freeswitch-users@lists.freeswitch.org Betreff: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily) MatzeMuc86 wrote:
I checked the code and found some positions where fh->channels have to be
1. This also depends on when the flags is set to SWITCH_FILE_FLAG_READ, right?
BTW, I am just curious what kind of application will you be making that requires a stereo. Do you care to tell us? Perhaps, once the readers understand what your application is, there may be some interests. ----- FreeSWITCH hosted on a Seagate DockStar with OpenWRT. -- View this message in context: http://freeswitch-users.2379917.n2.nabble.com/implementing-stereo-e-g-portau dio-to-test-it-easily-tp6061596p6064582.html Sent from the freeswitch-users mailing list archive at Nabble.com. _______________________________________________ FreeSWITCH-users mailing list FreeSWITCH-users@lists.freeswitch.org http://lists.freeswitch.org/mailman/listinfo/freeswitch-users UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users http://www.freeswitch.org
MatzeMuc86 wrote:
My idea: A conference room for regular sip clients but also special user clients which can receive stereo. Stereo is needed as those clients will get a special HRTF sound: different people are placed on different 3D positions in the room and you can hear them. This is NOT regular stereo sound but real 3D sound. Why is this better: Mixing all together to one mono channel, it is very difficult to distinguish between different people. Interesting links: http://en.wikipedia.org/wiki/Head-related_transfer_function and http://en.wikipedia.org/wiki/Cocktail_party_effect. There have been several tests (and there is literature as well) that proofs that it is much easier to follow conversations which use 3D sound like HRTF. And I want to do this not by some proprietary software like it is done by with Mumble by J. Feldmayer but with SIP to be able to connect also regular SIP clients (and regular phones or whatever I want). AFAIC, this indeed is a very interesting project. I am no expert nor have any idea how mathematically complex this will become as the conference room grows larger. I am hoping you will make the end product from project available to public. Best of luck.
----- FreeSWITCH hosted on a Seagate DockStar with OpenWRT. -- View this message in context: http://freeswitch-users.2379917.n2.nabble.com/implementing-stereo-e-g-portau... Sent from the freeswitch-users mailing list archive at Nabble.com.
SWITCH_FILE_FLAG_READ: I'm not sure what this does. It's somewhere else in the code.
It specifies that the file is being opened for reading (SWITCH_FILE_FLAG_READ) rather than writing (SWITCH_FILE_FLAG_WRITE). They actually wrap similar values in the APR library. -Steve On 25 February 2011 15:09, MatzeMuc86 <matzemuc86@gmail.com> wrote:
SWITCH_FILE_FLAG_READ: I'm not sure what this does. It's somewhere else in the code.
My idea: A conference room for regular sip clients but also special user clients which can receive stereo. Stereo is needed as those clients will get a special HRTF sound: different people are placed on different 3D positions in the room and you can hear them. This is NOT regular stereo sound but real 3D sound. Why is this better: Mixing all together to one mono channel, it is very difficult to distinguish between different people. Interesting links: http://en.wikipedia.org/wiki/Head-related_transfer_function and http://en.wikipedia.org/wiki/Cocktail_party_effect. There have been several tests (and there is literature as well) that proofs that it is much easier to follow conversations which use 3D sound like HRTF. And I want to do this not by some proprietary software like it is done by with Mumble by J. Feldmayer but with SIP to be able to connect also regular SIP clients (and regular phones or whatever I want).
-----Ursprüngliche Nachricht----- Von: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] Im Auftrag von mazilo Gesendet: Freitag, 25. Februar 2011 15:13 An: freeswitch-users@lists.freeswitch.org Betreff: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily)
MatzeMuc86 wrote:
I checked the code and found some positions where fh->channels have to be
1. This also depends on when the flags is set to SWITCH_FILE_FLAG_READ, right?
BTW, I am just curious what kind of application will you be making that requires a stereo. Do you care to tell us? Perhaps, once the readers understand what your application is, there may be some interests.
----- FreeSWITCH hosted on a Seagate DockStar with OpenWRT. -- View this message in context: http://freeswitch-users.2379917.n2.nabble.com/implementing-stereo-e-g-portau dio-to-test-it-easily-tp6061596p6064582.html Sent from the freeswitch-users mailing list archive at Nabble.com.
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Doing stereo codecs and playing stereo files are not the same. The main reason we do not have stereo completely implemented is there was not really any codec or devices that could handle it to bother testing with. We do record stereo files but as for playing them, there was not any real motivation since there was very little you can do with it talking to a mono sip phone. Its probably possible to make playing files to portaudio work but you would have to unblock the code that mixes it to mono and add support also to portaudio to understand the difference in the streams. If you want to do it yourself, like I believe I told you the first time, use FreeSWITCH and VoIP the way it already works for a long time until you completely understand the arena you are in before you try to add a new side entrance. On Fri, Feb 25, 2011 at 9:53 AM, Steven Ayre <steveayre@gmail.com> wrote:
SWITCH_FILE_FLAG_READ: I'm not sure what this does. It's somewhere else in the code.
It specifies that the file is being opened for reading (SWITCH_FILE_FLAG_READ) rather than writing (SWITCH_FILE_FLAG_WRITE). They actually wrap similar values in the APR library.
-Steve
On 25 February 2011 15:09, MatzeMuc86 <matzemuc86@gmail.com> wrote:
SWITCH_FILE_FLAG_READ: I'm not sure what this does. It's somewhere else in the code.
My idea: A conference room for regular sip clients but also special user clients which can receive stereo. Stereo is needed as those clients will get a special HRTF sound: different people are placed on different 3D positions in the room and you can hear them. This is NOT regular stereo sound but real 3D sound. Why is this better: Mixing all together to one mono channel, it is very difficult to distinguish between different people. Interesting links: http://en.wikipedia.org/wiki/Head-related_transfer_function and http://en.wikipedia.org/wiki/Cocktail_party_effect. There have been several tests (and there is literature as well) that proofs that it is much easier to follow conversations which use 3D sound like HRTF. And I want to do this not by some proprietary software like it is done by with Mumble by J. Feldmayer but with SIP to be able to connect also regular SIP clients (and regular phones or whatever I want).
-----Ursprüngliche Nachricht----- Von: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] Im Auftrag von mazilo Gesendet: Freitag, 25. Februar 2011 15:13 An: freeswitch-users@lists.freeswitch.org Betreff: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily)
MatzeMuc86 wrote:
I checked the code and found some positions where fh->channels have to be
1. This also depends on when the flags is set to SWITCH_FILE_FLAG_READ, right?
BTW, I am just curious what kind of application will you be making that requires a stereo. Do you care to tell us? Perhaps, once the readers understand what your application is, there may be some interests.
----- FreeSWITCH hosted on a Seagate DockStar with OpenWRT. -- View this message in context: http://freeswitch-users.2379917.n2.nabble.com/implementing-stereo-e-g-portau dio-to-test-it-easily-tp6061596p6064582.html Sent from the freeswitch-users mailing list archive at Nabble.com.
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-- Anthony Minessale II FreeSWITCH http://www.freeswitch.org/ ClueCon http://www.cluecon.com/ Twitter: http://twitter.com/FreeSWITCH_wire AIM: anthm MSN:anthony_minessale@hotmail.com GTALK/JABBER/PAYPAL:anthony.minessale@gmail.com IRC: irc.freenode.net #freeswitch FreeSWITCH Developer Conference sip:888@conference.freeswitch.org googletalk:conf+888@conference.freeswitch.org pstn:+19193869900
Here's an idea - it might be a little easier to make interoperate with other SIP devices. What if you built a conferencing endpoint that mixed all the audio locally into a 3D matrix? Each participant in the call could use any of the common codecs, but would have an extra SIP header than indicated their position in the sound field. Here's a bit of an overview: A regular Freeswitch system takes care of registering endpoints, routing, etc. Just like a normal PBX. The only thing special it would do is set add a custom SIP header with a person's sound field position, based on a directory variable. Each conference unit would be a stripped down freeswitch system with a custom modified mod_conference. In addition to mixing audio to mono like the regular mod_conference does, it would also generate a stereo mix, based on the position information of each participant. It could dump out the stereo audio directly to a named pipe, mod_shout, or directly to audio hardware. You could probably shoehorn a stereo input from hardware as well. Essentially, you are building a stereo conference phone. If you want to join up multiple conference units, just establish two sessions between each conference - one panned hard left, the other hard right. They can then use G722 without any modification. This probably isn't quite as nice as having true stereo codecs and media handling, but it may be easier to implement. After all, telecom is very much a mono world. -Tim
The main reason we do not have stereo completely implemented is there was not really any codec or devices that could handle it to bother testing with.
Hello, sorry for my late reply: @mazilo: I have not tested the HRTF my own but I know that it is not such an extreme thing. The point is: 5 people in a conference => every participant needs 4 other people mixed up => 5x4 = 20 HRTF mixings parallel => n*(n-1) complexity :-(. If I integrate this stuff in FreeSWITCH I will, of course, offer it as open source as well (we can try to integrate it or whatever the main developers want to have). But at first I need to get it working. @Steve: Thanks. Is there some documentation for which I am too stupid to find it? @Anthony: - Playing vs. Codec: Sounds logical! Codec: What about L16. I think there is a 1 and a 2 channel version available: http://en.wikipedia.org/wiki/RTP_audio_video_profile - I completely understand why there is no stereo until now. - Portaudio: I'm not sure if I really need this mod for my purpose. It was only a nice idea to test and debug how media is handled. - I understood SIP the way as it is only a protocol for "managing" things. The media flow uses RTP and RTP can use different codecs and different numbers of channels. The SDP can also handle different codecs for sending and receiving. Therefore, I thought, sending mono and receiving stereo is completely SIP regular!?? @tim: I'm not sure if I understood your idea completely in the right way: Your main idea is to use one sip session for each channel? But mixing would still be done by the server, not the client? How should I take care that the left and the right channels, processed by two different SIP + RTP sessions, are played simultaneously? Thanks to all your great support!!! MatzeMuc86 -----Ursprüngliche Nachricht----- Von: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] Im Auftrag von Tim St. Pierre Gesendet: Freitag, 25. Februar 2011 19:59 An: FreeSWITCH Users Help Betreff: Re: [Freeswitch-users] implementing stereo (e.g. portaudio to test it easily) Here's an idea - it might be a little easier to make interoperate with other SIP devices. What if you built a conferencing endpoint that mixed all the audio locally into a 3D matrix? Each participant in the call could use any of the common codecs, but would have an extra SIP header than indicated their position in the sound field. Here's a bit of an overview: A regular Freeswitch system takes care of registering endpoints, routing, etc. Just like a normal PBX. The only thing special it would do is set add a custom SIP header with a person's sound field position, based on a directory variable. Each conference unit would be a stripped down freeswitch system with a custom modified mod_conference. In addition to mixing audio to mono like the regular mod_conference does, it would also generate a stereo mix, based on the position information of each participant. It could dump out the stereo audio directly to a named pipe, mod_shout, or directly to audio hardware. You could probably shoehorn a stereo input from hardware as well. Essentially, you are building a stereo conference phone. If you want to join up multiple conference units, just establish two sessions between each conference - one panned hard left, the other hard right. They can then use G722 without any modification. This probably isn't quite as nice as having true stereo codecs and media handling, but it may be easier to implement. After all, telecom is very much a mono world. -Tim
The main reason we do not have stereo completely implemented is there was not really any codec or devices that could handle it to bother testing with.
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participants (7)
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Anthony Minessale
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Grmt
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MatzeMuc86
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mazilo
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Michael Collins
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Steven Ayre
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Tim St. Pierre