Re: Frame drop when Using GMSK en UDP

[Alex Roberts]

Quenten, Have you looked at any of the gr-dtv examples? Instead of pulling into GRC with UDP, you could pull the video stream and convert to mpeg-TS with either gstreamer or ffmpeg and stream it to a fifo file. The gr-dtv examples are great for reading in TS files and broadcasting. I've done this with gstreamer and gr-isdbt.

On Fri, Apr 24, 2020 at 8:57 AM Marcus Müller <address@hidden> wrote:

Hi Quenten,

do you mean a bandwidth of 1.25 MHz, up to at most 20 MHz? Or do you
mean carrier frequency? Or do you mean occupied spectrum spans from 1.25
MHz to 20 MHz (i.e. 18.75 MHz bandwidth)? In the latter two cases: I'd
be interested in how you build a very wideband antenna for these
extraordinarily low frequencies; that is very hard!

I don't see how that precludes OFDM; quite on the contrary, all three
options actually sounds like a very classical use cases of OFDM.

Best regards,

Marcus

On 4/24/20 1:59 PM, Quenten . wrote:
> Thanks for the tip.
> I did 1 and 2  (but didn't find  a gr-digital map in the examples on
> GRC software), and what do you mean with: "it's misconfigured".
> Also you say that OFDM would be interesting(It normally would) but
> because of some circumstances I can't use OFDM. It is because its
> frequency spectrum is to low (1.25MHz to 20MHz). But the frequency
> spectrum that I am later gonna use is from 300 MHz to 3.8GHz (because
> I am gonna use a bladeRFx115 eventually as the HW component).
>
> Best regards,
>
> Quenten
>
> Op vr 24 apr. 2020 om 12:32 schreef Marcus Müller
> <address@hidden <mailto:address@hidden>>:
>
>     Hi Quenten,
>
>     you're using multiple deprecated blocks; especially the packet
>     encooder/decoder are simply buggy and drop data. (Also, it's
>     misconfigured, but properly configuring it won't help. Don't use it.)
>
>     Also, while your computer might be too slow, the Throttle guarantees
>     that the UDP source has to drop UDP packets if your data rate is
>     higher
>     than 500 kB/s...
>
>     So,
>
>     1. Replace deprecated WX GUI with Qt GUI
>
>     2. Remove all throttles
>
>     3. replace packet encoder/decoder with appropriate packet
>     transmission
>     example from gr-digital
>
>
>     You'll notice that a video stream is a lot of data, and that 500 kHz
>     bandwidth simply won't do with GMSK to transport that amount of data.
>     Which means you'll need more bandwidth. Which means you'll see a
>     frequency-selective channel. Which means you need some
>     equalization, or
>     a multicarrier scheme! The OFDM-examples in gr-digital will be of
>     most
>     interest to you.
>
>     Best regards,
>
>     Marcus
>
>     On 4/24/20 10:05 AM, Quenten . wrote:
>     > Hello,
>     > I am trying to stream (de)mod a live video with to use of GNU
>     radio.
>     > from my windows 10 PC. These are the steps I follow:
>     > 1)Steam using OBS to an RTMP server
>     > 2)Use ffmpeg to get this stream form OBS and send it to UDP
>     (port:9999
>     > ; IP:127.0.0.1).
>     > 3) Do GMSK mod en demod
>     > 4) Save it to a file sink
>     >
>     > Here is the program:
>     > image.png
>     > I also get a warning from GNU: *WARN: Too much data; dropping
>     packet.
>     > *But I think this is because my PC is to slow.
>     >
>     > If someone can help it would be appreciated.
>     >
>     > Best regards,
>     >
>     > Q
>