Date: Tue, 16 May 2006 11:19:13 +0200 From: =?ISO-8859-1?Q?Dirk_Thannh=E4user?= <dt@dtinnovations.com> To: freebsd-isdn@freebsd.org Subject: Re: Sound delay in i4b Message-ID: <6F0386D8-FEB3-45F1-9C50-F0104D89D813@dtinnovations.com> In-Reply-To: <200605151403.47796.hselasky@c2i.net> References: <0CDCE7F4-A7D2-4379-9560-516FFF3350C6@dtinnovations.com> <200605150938.28035.hselasky@c2i.net> <CE5A2D0A-B91D-423C-B1C2-80A74F8EA873@dtinnovations.com> <200605151403.47796.hselasky@c2i.net>
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On May 15, 2006, at 2:03 PM, Hans Petter Selasky wrote: > On Monday 15 May 2006 12:20, Dirk Thannh=E4user wrote: >> On May 15, 2006, at 9:38 AM, Hans Petter Selasky wrote: >>> Hi, >>> >>> On Sunday 14 May 2006 22:57, Dirk Thannh=E4user wrote: >>>> On May 14, 2006, at 3:18 PM, Hans Petter Selasky wrote: >>>>> Do you have SVN installed? >>>> >>>> yes i have. I checked out the version which included both, the i4b >>>> and the chan_capi. Is ist possible that my version was to old? >>>> I just did a new checkout. >>>> Subversion says "Checked out revision 264." >>> >>> That should be the latest version. It was fixed in "Revision 257", >>> which was >>> after that I released Version 1.6.0 in April. >> >> Hmm. i compiled the latest release (i4b and chan_capi) yesterday and >> tested it with the echo test application. The delay is the same as >> before. >> When I call the server internal (My Phone -> ISDNCard(NT) -> Asterisk >> (1.2.4) (isdnd not running. cards set to TE/NT mode via "isdnconfig" >> command . The delay in the echo test application remains unchanged at >> about 250ms to half a second. (not measured, it's just my feeling, >> but i know the difference to the zaptel FreeBSD driver). My machine >> is a Siemens Scenic L (1.6Ghz/512MB RAM). That schould be enough >> power to get low latency. > > Sure, but that is only when the computer is not loaded. 50ms =20 > interrupts were > chosen because it will allow one to heavily load the computer =20 > without loosing > any data. > >> How easy would it be to play around with changing latencey. Should i >> take a look to the chan_capi sources to get latency changed? >> > > It is not very difficult to play around to get the latency down. > > Edit: /usr/src/sys/i4b/layer1/ihfc2/i4b_ihfc2_drv.c > > Change: > > .s_ctmt_pci =3D 0x00 | 0x17, /* t50ms + trans */ > > Into: > > .s_ctmt_pci =3D 0x00 | 0x13, /* t25ms + trans */ > > > And change: > /* default AUDIO limit =3D=3D 100ms of data */ > > /* limit fifo usage to 800 bytes(100ms) > * - Assuming that about 400 bytes(50ms) > * is needed for each interrupt: > */ > f->Z_min_free -=3D 800; > Into: > > /* default AUDIO limit =3D=3D 100ms of data */ > > /* limit fifo usage to 800 bytes(100ms) > * - Assuming that about 400 bytes(50ms) > * is needed for each interrupt: > */ > f->Z_min_free -=3D 400; i played around a lot with changing numbers, but i was not able to =20 get latency down. did you ever test with the asterisk echo test application? (maybe =20 that latency is only here a problem) Is it possible that there is a =20 bug inside the application? But on the other hand it worked fine with =20= the zaptel drivers. I think i will need more time to study sources :-) > >>>> Are there any "cheap" HFC-4S cards out there for testing? >>> >>> There exist some developer kits, but they are not so easy to get a >>> hand on. >>> The only place I know that sales HFC-4S are: >> >> A developer Kit would be the card of my choice. >> Does Bero sell them or shoud i contact colognechip? > > I don't know. > >> >>> http://shop.beronet.com >>> >>> And maybe "http://www.junghanns.net/". >>> >>>> I think that this also means that i am not able to run one card >>>> (HFC-1S) in slave mode, getting the clock from the other to keep =20= >>>> them >>>> in sync without soldering. >>> >>> Yes. >>> >>>> For Voice over IP a huger delay might be ok. thats also my opinion. >>>> but what about Faxing over ISDN. Here I think latency is an =20 >>>> important >>>> issue. (didn't test the CAPI Fax receiption, yet) >>> >>> Faxing works, but really you need to use line interconnect to get >>> faxing >>> working reliably. Or you can receive the fax in asterisk. That also >>> works. >> >> Does it also work with about 250ms delay? (it exists on both sides >> from my NT-Card to asterisk and also from the TE-Card to asterisk >> may be that i did something wrong compiling the sources although i >> cleaned the BSD sourcetree applied the patches again an then started >> compiling the get a "fresh" state an no confusion with the older >> release which was installed before. > > Yes, faxing works with 250ms delay. > > --HPS
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