Re: [wsjt-devel] Audio input from RTP stream?

2018-03-28 Thread Joe Taylor
Hi Alex, These sound like good ideas to me. A mechanism for sending I/Q data into WSJT-X has been on our back-burner "To Do" list for some time. But as you can probably guess, I'm only superficially familiar with the protocols you're considering. Bill will probably have a more useful

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-28 Thread Alex, VE3NEA
Hello developers, I am looking into supporting the RTP+RTCP protocol in CW Skimmer, and I want to do this in a way compatible with other software, including WSJTX. RTP seems to be the best way of exchanging the I/Q data between the programs, but it needs to be complemented with another

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-08 Thread Игорь Ч via wsjt-devel
Hello Phil, . >Igor, the whole point of playing out silence is to maintain >synchronization. If, for example, the sampling rate is 48 kHz and your >RTP packets each contain 240 samples (5 milliseconds), then I would >replace a single missing packet with 240 samples of binary zeroes. Your >signal

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-07 Thread Phil Karn
On 3/6/18 08:05, Bill Somerville wrote: > > Our experience of users using the Elecraft remote kit using IP streaming > is that latency and delay are a problem, this being because of our > dependence on external wall clock synchronization. Can RTP provide > absolute time-stamp information that we

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-07 Thread Phil Karn
On 3/7/18 01:33, Игорь Ч via wsjt-devel wrote: > Playing out silence in place of the lost packets is not a good idea: > it will distrurb sychronization and will bring wrong Delta Time values > to the weak signals at demodulation. I would suggest usage of some > averaging instead of the silence.

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-07 Thread Игорь Ч via wsjt-devel
Hello Phil, >I implemented RTP in about a page of C code, not counting all of the >UNIX/Linux system calls needed to set up multicast sockets. That's >actually the only hard part. With RTP I just check that the next packet >is in sequence, drop any old duplicates, and play out silence in place >of

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-07 Thread Phil Karn
To Bill (and Joe), It just occurred to me that I could multicast my receiver output to you in the frequency domain. UDP already provides the necessary framing. We just define that as a new RTP "codec type". I use fast convolution with overlap-and-save for filtering, so as long as I tell you the

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-07 Thread Phil Karn
On 3/6/18 08:05, Bill Somerville wrote: > not very hard at all. The audio in WSJT-X is via a Qt I/O Device > abstraction and making a UDP server that joins a multicast group to > receive and send audio would only require a thin layer to manage > datagram reception and transmission converting

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-06 Thread Phil Karn
On 3/6/18 06:48, Joe Taylor wrote: > Hi Phil, > > Your idea sounds reasonable.  It might be a good way to enable wideband > receiving -- that is, reception (of FT8, say) over a passband > significantly greater than 5 kHz, currently the practical limit.  The > popularity of FT8 on the HF bands

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-06 Thread Bill Somerville
On 06/03/2018 06:29, Phil Karn wrote: How hard would it be for WJST to accept receive audio from a RTP (Real Time Protocol) multicast network stream? Hi Phil, not very hard at all. The audio in WSJT-X is via a Qt I/O Device abstraction and making a UDP server that joins a multicast group to

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-06 Thread Michael Besemer
FT8 is already encroaching on the PSK subbands (or in the case of 17 meters right on top of the PSK subband) and probably others too.  PLEASE be a good neighbor and don't do anything to make it worse.  Everyone needs to share a very limited resource.  Just because FT8 is popular does not

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-06 Thread Joe Taylor
Hi Phil, Your idea sounds reasonable. It might be a good way to enable wideband receiving -- that is, reception (of FT8, say) over a passband significantly greater than 5 kHz, currently the practical limit. The popularity of FT8 on the HF bands implies that wider sub-bands would be very

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-06 Thread Phil Karn
On 3/5/18 23:24, Borja Marcos wrote: > That would be really awesome, defining some standard “audio bus” for > radio applications. Well, there's really not much to define since the work has already been done for us by the IETF (Internet Engineering Task Force). Multicasting is heavily used on

Re: [wsjt-devel] Audio input from RTP stream?

2018-03-05 Thread Borja Marcos
> On 6 Mar 2018, at 07:29, Phil Karn wrote: > > How hard would it be for WJST to accept receive audio from a RTP (Real > Time Protocol) multicast network stream? > > My receiver outputs uncompressed audio as a standard RTP/UDP/IP > multicast stream containing mono or stereo